Weather Conversion Calculators   
Courtesy of NWS Boston

Scroll down to see text tables.
 

Convert
Temperature

Enter temperature in one blank to convert to the other scale.

Fahrenheit:
Celsius:
Kelvin:
 

Calculate
Wind Chill

Enter temperature and wind speed to compute wind chill.

Temperature:
F C
Wind Speed:
MPH Knots
Wind Chill:
 
 

Calculate
Heat Index

Enter temperature and relative humidity below to calculate heat index

Temperature:
F C
Relative Humidity:
Heat Index:
 

Wind Speed
Conversions

Enter a speed into any blank to convert to all other wind speeds.

MPH:
Km/h:
Knots:
Meters/Second:
 
 

Calculate
Relative Humidity

Enter temperature and dewpoint below to calculate relative humidity

Temperature:
F C
Dewpoint:
Relative Humidity:
 

Convert
Pressure

Enter a pressure in one blank to convert to the other pressures.

Millibars:
Inches:
Millimeters:
 
 

Convert
Precipitation

Enter a depth into any blank to convert to other units .

Inches (hundredths) :
Inches:
Millimeters:
Centimeters:

 

Celsius to Fahrenheit Conversion Table

°C     °F         °C    °F        °C   °F          °C     °F 

50   122.0       27   80.6        4   39.2        -19   -2.2
49   120.2       26   78.8        3   37.4        -20   -4.0
48   118.4       25   77.0        2   35.6        -21   -5.8
47   116.6       24   75.2        1   33.8        -22   -7.6
46   114.8       23   73.4        0   32.0        -23   -9.4
45   113.0       22   71.6       -1   30.2        -24  -11.2
44   111.2       21   69.8       -2   28.4        -25  -13.0
43   109.4       20   68.0       -3   26.6        -26  -14.8
42   107.6       19   66.2       -4   24.8        -27  -16.6
41   105.8       18   64.4       -5   23.0        -28  -18.4
40   104.0       17   62.6       -6   21.2        -29  -20.2
39   102.2       16   60.8       -7   19.4        -30  -22.0
38   100.4       15   59.0       -8   17.6        -31  -23.8
37    98.6       14   57.2       -9   15.8        -32  -25.6
36    96.8       13   55.4      -10   14.0        -33  -27.4
35    95.0       12   53.6      -11   12.2        -34  -29.2
34    93.2       11   51.8      -12   10.4        -35  -31.0
33    91.4       10   50.0      -13    8.6        -36  -32.8
32    89.6        9   48.2      -14    6.8        -37  -34.6
31    87.8        8   46.4      -15    5.0        -38  -36.4
30    86.0        7   44.6      -16    3.2        -39  -38.2
29    84.2        6   42.8      -17    1.4        -40  -40.0
28    82.4        5   41.0      -18   -0.4                  

Fahrenheit to Celsius Conversion Table

°F     °C         °F    °C          °F    °C           °F    °C

125   51.6        83   28.3         41    5.0          -1  -18.3
124   51.1        82   27.8         40    4.4          -2  -18.9
123   50.5        81   27.2         39    3.9          -3  -19.4
122   50.0        80   26.6         38    3.3          -4  -20.0
121   49.4        79   26.1         37    2.8          -5  -20.5
120   48.8        78   25.5         36    2.2          -6  -21.1
119   48.3        77   25.0         35    1.7          -7  -21.6
118   47.7        76   24.4         34    1.1          -8  -22.2
117   47.2        75   23.9         33    0.6          -9  -22.8
116   46.6        74   23.3         32    0.0         -10  -23.3
115   46.1        73   22.8         31   -0.6         -11  -23.9
114   45.5        72   22.2         30   -1.1         -12  -24.4
113   45.0        71   21.6         29   -1.7         -13  -25.0
112   44.4        70   21.1         28   -2.2         -14  -25.5
111   43.8        69   20.5         27   -2.8         -15  -26.1
110   43.3        68   20.0         26   -3.3         -16  -26.6
109   42.7        67   19.4         25   -3.9         -17  -27.2
108   42.2        66   18.9         24   -4.4         -18  -27.8
107   41.6        65   18.3         23   -5.0         -19  -28.3
106   41.1        64   17.8         22   -5.6         -20  -28.9
105   40.5        63   17.2         21   -6.1         -21  -29.4
104   40.0        62   16.7         20   -6.7         -22  -30.0
103   39.4        61   16.1         19   -7.2         -23  -30.5
102   38.9        60   15.5         18   -7.8         -24  -31.1
101   38.3        59   15.0         17   -8.3         -25  -31.6
100   37.7        58   14.4         16   -8.9         -26  -32.2
 99   37.2        57   13.9         15   -9.4         -27  -32.7
 98   36.6        56   13.3         14  -10.0         -28  -33.3
 97   36.1        55   12.8         13  -10.5         -29  -33.9
 96   35.5        54   12.2         12  -11.1         -30  -34.4
 95   35.0        53   11.7         11  -11.7         -31  -35.0
 94   34.4        52   11.1         10  -12.2         -32  -35.5
 93   33.9        51   10.5          9  -12.8         -33  -36.1
 92   33.3        50   10.0          8  -13.3         -34  -36.6
 91   32.7        49    9.4          7  -13.9         -35  -37.2
 90   32.2        48    8.9          6  -14.4         -36  -37.7
 89   31.6        47    8.3          5  -15.0         -37  -38.3
 88   31.1        46    7.8          4  -15.5         -38  -38.9
 87   30.5        45    7.2          3  -16.1         -39  -39.4
 86   30.0        44    6.7          2  -16.7         -40  -40.0
 85   29.4        43    6.1          1  -17.2                   
 84   28.9        42    5.6          0  -17.8                   

Inches of Mercury to Millibars Conversion Chart

In Hg     Mb          In Hg     Mb           In Hg     Mb           In Hg     Mb

29.00   982.06        29.50    998.99        30.00   1015.92        30.50   1032.85
29.01   982.39        29.51    999.33        30.01   1016.26        30.51   1033.19
29.02   982.73        29.52    999.67        30.02   1016.60        30.52   1033.53
29.03   983.07        29.53   1000.00        30.03   1016.94        30.53   1033.87
29.04   983.41        29.54   1000.34        30.04   1017.27        30.54   1034.21
29.05   983.75        29.55   1000.68        30.05   1017.61        30.55   1034.55
29.06   984.09        29.56   1001.02        30.06   1017.95        30.56   1034.88
29.07   984.43        29.57   1001.36        30.07   1018.29        30.57   1035.22
29.08   984.77        29.58   1001.70        30.08   1018.63        30.58   1035.56
29.09   985.10        29.59   1002.04        30.09   1018.97        30.59   1035.90
29.10   985.44        29.60   1002.37        30.10   1019.31        30.60   1036.24
29.11   985.78        29.61   1002.71        30.11   1019.65        30.61   1036.58
29.12   986.12        29.62   1003.05        30.12   1019.98        30.62   1036.92
29.13   986.46        29.63   1003.39        30.13   1020.32        30.63   1037.25
29.14   986.80        29.64   1003.73        30.14   1020.66        30.64   1037.59
29.15   987.14        29.65   1004.07        30.15   1021.00        30.65   1037.93
29.16   987.47        29.66   1004.41        30.16   1021.34        30.66   1038.27
29.17   987.81        29.67   1004.74        30.17   1021.68        30.67   1038.61
29.18   988.15        29.68   1005.08        30.18   1022.02        30.68   1038.95
29.19   988.49        29.69   1005.42        30.19   1022.35        30.69   1039.29
29.20   988.83        29.70   1005.76        30.20   1022.69        30.70   1039.62
29.21   989.17        29.71   1006.10        30.21   1023.03        30.71   1039.96
29.22   989.51        29.72   1006.44        30.22   1023.37        30.72   1040.30
29.23   989.84        29.73   1006.78        30.23   1023.71        30.73   1040.64
29.24   990.18        29.74   1007.12        30.24   1024.05        30.74   1040.98
29.25   990.52        29.75   1007.45        30.25   1024.39        30.75   1041.32
29.26   990.86        29.76   1007.79        30.26   1024.72        30.76   1041.66
29.27   991.20        29.77   1008.13        30.27   1025.06        30.77   1042.00
29.28   991.54        29.78   1008.47        30.28   1025.40        30.78   1042.33
29.29   991.88        29.79   1008.81        30.29   1025.74        30.79   1042.67
29.30   992.22        29.80   1009.15        30.30   1026.08        30.80   1043.01
29.31   992.55        29.81   1009.49        30.31   1026.42        30.81   1043.35
29.32   992.89        29.82   1009.82        30.32   1026.76        30.82   1043.69
29.33   993.23        29.83   1010.16        30.33   1027.10        30.83   1044.03
29.34   993.57        29.84   1010.50        30.34   1027.43        30.84   1044.37
29.35   993.91        29.85   1010.84        30.35   1027.77        30.85   1044.70
29.36   994.25        29.86   1011.18        30.36   1028.11        30.86   1045.04
29.37   994.59        29.87   1011.52        30.37   1028.45        30.87   1045.38
29.38   994.92        29.88   1011.86        30.38   1028.79        30.88   1045.72
29.39   995.26        29.89   1012.19        30.39   1029.13        30.89   1046.06
29.40   995.60        29.90   1012.53        30.40   1029.47        30.90   1046.40
29.41   995.94        29.91   1012.87        30.41   1029.80        30.91   1046.74
29.42   996.28        29.92   1013.21        30.42   1030.14        30.92   1047.07
29.43   996.62        29.93   1013.55        30.43   1030.48        30.93   1047.41
29.44   996.96        29.94   1013.89        30.44   1030.82        30.94   1047.75
29.45   997.29        29.95   1014.23        30.45   1031.16        30.95   1048.09
29.46   997.63        29.96   1014.57        30.46   1031.50        30.96   1048.43
29.47   997.97        29.97   1014.90        30.47   1031.84        30.97   1048.77
29.48   998.31        29.98   1015.24        30.48   1032.17        30.98   1049.11
29.49   998.65        29.99   1015.58        30.49   1032.51        30.99   1049.45

Millibars to Inches of Mercury Conversion Chart

  Mb    In Hg         Mb    In Hg         Mb    In Hg         Mb    In Hg

980.00  28.94       1000.00 29.53       1020.00 30.12       1040.00 30.71
980.33  28.95       1000.33 29.54       1020.33 30.13       1040.33 30.72
980.67  28.96       1000.67 29.55       1020.67 30.14       1040.67 30.73
981.00  28.97       1001.00 29.56       1021.00 30.15       1041.00 30.74
981.33  28.98       1001.33 29.57       1021.33 30.16       1041.33 30.75
981.67  28.99       1001.67 29.58       1021.67 30.17       1041.67 30.76
982.00  29.00       1002.00 29.59       1022.00 30.18       1042.00 30.77
982.33  29.01       1002.33 29.60       1022.33 30.19       1042.33 30.78
982.67  29.02       1002.67 29.61       1022.67 30.20       1042.67 30.79
983.00  29.03       1003.00 29.62       1023.00 30.21       1043.00 30.80
983.33  29.04       1003.33 29.63       1023.33 30.22       1043.33 30.81
983.67  29.05       1003.67 29.64       1023.67 30.23       1043.67 30.82
984.00  29.06       1004.00 29.65       1024.00 30.24       1044.00 30.83
984.33  29.07       1004.33 29.66       1024.33 30.25       1044.33 30.84
984.67  29.08       1004.67 29.67       1024.67 30.26       1044.67 30.85
985.00  29.09       1005.00 29.68       1025.00 30.27       1045.00 30.86
985.33  29.10       1005.33 29.69       1025.33 30.28       1045.33 30.87
985.67  29.11       1005.67 29.70       1025.67 30.29       1045.67 30.88
986.00  29.12       1006.00 29.71       1026.00 30.30       1046.00 30.89
986.33  29.13       1006.33 29.72       1026.33 30.31       1046.33 30.90
986.67  29.14       1006.67 29.73       1026.67 30.32       1046.67 30.91
987.00  29.15       1007.00 29.74       1027.00 30.33       1047.00 30.92
987.33  29.16       1007.33 29.75       1027.33 30.34       1047.33 30.93
987.67  29.17       1007.67 29.76       1027.67 30.35       1047.67 30.94
988.00  29.18       1008.00 29.77       1028.00 30.36       1048.00 30.95
988.33  29.19       1008.33 29.78       1028.33 30.37       1048.33 30.96
988.67  29.20       1008.67 29.79       1028.67 30.38       1048.67 30.97
989.00  29.21       1009.00 29.80       1029.00 30.39       1049.00 30.98
989.33  29.21       1009.33 29.81       1029.33 30.40       1049.33 30.99
989.67  29.22       1009.67 29.82       1029.67 30.41       1049.67 31.00
990.00  29.23       1010.00 29.83       1030.00 30.42       1050.00 31.01
990.33  29.24       1010.33 29.84       1030.33 30.43       1050.33 31.02
990.67  29.25       1010.67 29.84       1030.67 30.44       1050.67 31.03
991.00  29.26       1011.00 29.85       1031.00 30.45       1051.00 31.04
991.33  29.27       1011.33 29.86       1031.33 30.46       1051.33 31.05
991.67  29.28       1011.67 29.87       1031.67 30.46       1051.67 31.06
992.00  29.29       1012.00 29.88       1032.00 30.47       1052.00 31.07
992.33  29.30       1012.33 29.89       1032.33 30.48       1052.33 31.08
992.67  29.31       1012.67 29.90       1032.67 30.49       1052.67 31.09
993.00  29.32       1013.00 29.91       1033.00 30.50       1053.00 31.09
993.33  29.33       1013.33 29.92       1033.33 30.51       1053.33 31.10
993.67  29.34       1013.67 29.93       1033.67 30.52       1053.67 31.11
994.00  29.35       1014.00 29.94       1034.00 30.53       1054.00 31.12
994.33  29.36       1014.33 29.95       1034.33 30.54       1054.33 31.13
994.67  29.37       1014.67 29.96       1034.67 30.55       1054.67 31.14
995.00  29.38       1015.00 29.97       1035.00 30.56       1055.00 31.15
995.33  29.39       1015.33 29.98       1035.33 30.57       1055.33 31.16
995.67  29.40       1015.67 29.99       1035.67 30.58       1055.67 31.17
996.00  29.41       1016.00 30.00       1036.00 30.59       1056.00 31.18
996.33  29.42       1016.33 30.01       1036.33 30.60       1056.33 31.19
996.67  29.43       1016.67 30.02       1036.67 30.61       1056.67 31.20
997.00  29.44       1017.00 30.03       1037.00 30.62       1057.00 31.21
997.33  29.45       1017.33 30.04       1037.33 30.63       1057.33 31.22
997.67  29.46       1017.67 30.05       1037.67 30.64       1057.67 31.23
998.00  29.47       1018.00 30.06       1038.00 30.65       1058.00 31.24
998.33  29.48       1018.33 30.07       1038.33 30.66       1058.33 31.25
998.67  29.49       1018.67 30.08       1038.67 30.67       1058.67 31.26
999.00  29.50       1019.00 30.09       1039.00 30.68       1059.00 31.27
999.33  29.51       1019.33 30.10       1039.33 30.69       1059.33 31.28
999.67  29.52       1019.67 30.11       1039.67 30.70       1059.67 31.29

MPH to Knots to Meters Per Second Conversion Chart

MPH     Kts    m/sec            MPH      Kts    m/sec

 1      0.9     0.4             51      44.3    22.8
 2      1.7     0.9             52      45.2    23.2
 3      2.6     1.3             53      46.1    23.7
 4      3.5     1.8             54      46.9    24.1
 5      4.3     2.2             55      47.8    24.6
 6      5.2     2.7             56      48.7    25.0
 7      6.1     3.1             57      49.5    25.5
 8      7.0     3.6             58      50.4    25.9
 9      7.8     4.0             59      51.3    26.4
10      8.7     4.5             60      52.1    26.8
11      9.6     4.9             61      53.0    27.3
12     10.4     5.4             62      53.9    27.7
13     11.3     5.8             63      54.7    28.2
14     12.2     6.3             64      55.6    28.6
15     13.0     6.7             65      56.5    29.1
16     13.9     7.2             66      57.4    29.5
17     14.8     7.6             67      58.2    30.0
18     15.6     8.0             68      59.1    30.4
19     16.5     8.5             69      60.0    30.8
20     17.4     8.9             70      60.8    31.3
21     18.2     9.4             71      61.7    31.7
22     19.1     9.8             72      62.6    32.2
23     20.0    10.3             73      63.4    32.6
24     20.9    10.7             74      64.3    33.1
25     21.7    11.2             75      65.2    33.5
26     22.6    11.6             76      66.0    34.0
27     23.5    12.1             77      66.9    34.4
28     24.3    12.5             78      67.8    34.9
29     25.2    13.0             79      68.6    35.3
30     26.1    13.4             80      69.5    35.8
31     26.9    13.9             81      70.4    36.2
32     27.8    14.3             82      71.3    36.7
33     28.7    14.8             83      72.1    37.1
34     29.5    15.2             84      73.0    37.6
35     30.4    15.6             85      73.9    38.0
36     31.3    16.1             86      74.7    38.4
37     32.2    16.5             87      75.6    38.9
38     33.0    17.0             88      76.5    39.3
39     33.9    17.4             89      77.3    39.8
40     34.8    17.9             90      78.2    40.2
41     35.6    18.3             91      79.1    40.7
42     36.5    18.8             92      79.9    41.1
43     37.4    19.2             93      80.8    41.6
44     38.2    19.7             94      81.7    42.0
45     39.1    20.1             95      82.6    42.5
46     40.0    20.6             96      83.4    42.9
47     40.8    21.0             97      84.3    43.4
48     41.7    21.5             98      85.2    43.8
49     42.6    21.9             99      86.0    44.3
50     43.4    22.4            100      86.9    44.7

Knots to MPH to Meters Per Second Conversion Chart

Knots    MPH    m/sec          Knots      MPH     m/sec

 1       1.2     0.5            51       58.7     26.3
 2       2.3     1.0            52       59.8     26.8
 3       3.5     1.5            53       61.0     27.3
 4       4.6     2.1            54       62.1     27.8
 5       5.8     2.6            55       63.3     28.3
 6       6.9     3.1            56       64.4     28.8
 7       8.1     3.6            57       65.6     29.3
 8       9.2     4.1            58       66.7     29.9
 9      10.4     4.6            59       67.9     30.4
10      11.5     5.1            60       69.0     30.9
11      12.7     5.7            61       70.2     31.4
12      13.8     6.2            62       71.3     31.9
13      15.0     6.7            63       72.5     32.4
14      16.1     7.2            64       73.7     32.9
15      17.3     7.7            65       74.8     33.5
16      18.4     8.2            66       76.0     34.0
17      19.6     8.8            67       77.1     34.5
18      20.7     9.3            68       78.3     35.0
19      21.9     9.8            69       79.4     35.5
20      23.0    10.3            70       80.6     36.0
21      24.2    10.8            71       81.7     36.6
22      25.3    11.3            72       82.9     37.1
23      26.5    11.8            73       84.0     37.6
24      27.6    12.4            74       85.2     38.1
25      28.8    12.9            75       86.3     38.6
26      29.9    13.4            76       87.5     39.1
27      31.1    13.9            77       88.6     39.6
28      32.2    14.4            78       89.8     40.2
29      33.4    14.9            79       90.9     40.7
30      34.5    15.4            80       92.1     41.2
31      35.7    16.0            81       93.2     41.7
32      36.8    16.5            82       94.4     42.2
33      38.0    17.0            83       95.5     42.7
34      39.1    17.5            84       96.7     43.2
35      40.3    18.0            85       97.8     43.8
36      41.4    18.5            86       99.0     44.3
37      42.6    19.0            87      100.1     44.8
38      43.7    19.6            88      101.3     45.3
39      44.9    20.1            89      102.4     45.8
40      46.0    20.6            90      103.6     46.3
41      47.2    21.1            91      104.7     46.8
42      48.3    21.6            92      105.9     47.4
43      49.5    22.1            93      107.0     47.9
44      50.6    22.7            94      108.2     48.4
45      51.8    23.2            95      109.3     48.9
46      52.9    23.7            96      110.5     49.4
47      54.1    24.2            97      111.6     49.9
48      55.2    24.7            98      112.8     50.4
49      56.4    25.2            99      113.9     51.0
50      57.5    25.7           100      115.1     51.5

Values in a Standard Atmosphere

Elevation        Temperature        Pressure
(feet)        (degrees °C)          (Mb)

     0             15.0             1013
   500             14.0              995
 1,000             13.0              977
 1,500             12.0              959
 2,000             11.0              942
 2,500             10.0              925
 3,000              9.1              908
 3,500              8.1              891
 4,000              7.1              875
 4,500              6.1              859
 5,000              5.1              843
 5,500              4.1              827
 6,000              3.1              812
 6,500              2.1              797
 7,000              1.1              782
 7,500              0.1              767
 8,000             -0.9              752
 8,500             -1.8              738
 9,000             -2.8              724
 9,500             -3.8              710
 10,000             -4.8              697 
 10,500             -5.8              683 
 11,000             -6.8              670 
 11,500             -7.8              657 
 12,000             -8.8              644 
 12,500             -9.8              632 
 13,000            -10.8              619 
 13,500            -11.8              607 
 14,000            -12.7              595 
 14,500            -13.7              583 
 15,000            -14.7              572 
 15,500            -15.7              560 
 16,000            -16.7              549 
 16,500            -17.7              538 
 17,000            -18.7              527 
 17,500            -19.7              516 
 18,000            -20.7              506 
 18,500            -21.7              495 
 19,000            -22.7              485 
 19,500            -23.6              475 
 20,000            -24.6              465 
 20,500            -25.6              456 
 21,000            -26.6              446 
21,500            -27.6              437
22,000            -28.6              428
22,500            -29.6              419
23,000            -30.6              410
23,500            -31.6              401
24,000            -32.6              392
24,500            -33.6              384
25,000            -34.5              376
25,500            -35.5              368
26,000            -36.5              360
26,500            -37.5              352
27,000            -38.5              344
27,500            -39.5              336
28,000            -40.5              329
28,500            -41.5              322
29,000            -42.5              315
29,500            -43.5              307
30,000            -44.5              301
30,500            -45.4              294
31,000            -46.4              287
31,500            -47.4              281
32,000            -48.4              274
32,500            -49.4              268
33,000            -50.4              262
33,500            -51.4              256
34,000            -52.4              250
34,500            -53.4              244
35,000            -54.4              238
35,500            -55.4              232
36,000            -56.3              225
36,500            -57.3              219
37,000            -58.3              213
37,500            -59.3              207
38,000            -60.3              200
38,500            -61.3              194
39,000            -62.3              188
39,500            -63.3              182
40,000            -64.3              176


 


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Weather Related Converters and Calculators

Other Weather Related
Converters and Calculators




Below is a list of weather based calculator, conversion charts and converter programs available for use. Some of these are directly related to interest in weather and some are of indirect interest; often they are of interest in our day to day lives. We have written these or provided these for actual use and convenience, rather than for strictly educational purposes, though homework is a frequent and valid use. Each program applet in this particular group has a highly functional purpose. Each menu item has a descriptive pop-up that will appear, giving detailed information of that selection, as the mouse is rolled over the menu item. We are always receptive to comments or suggestions you may have. Enjoy!


Above Sea Level Barometer Reading Correction Calculator
Atmospheric Pressure Apparent Altitude Correction Calculator
Canadian Humidex Calculator
Celsius and Fahrenheit Conversion Details
Celsius, Fahrenheit, Kelvin, Réaumur, and Rankine Temperature Conversion
Dew Point And Relative Humidity Calculator
Gravity Barometer Reading Correction Calculator
Gravity, Elevation And Temperature Barometer Reading Correction Calculator
Highway Crosswind Calculator
Highway Weather Factors
Mooned!
Lifted Index Calculator
Meteorology Conversion Factors Table
Pressure Altitude Calculator
Pressure Altitude Conversion To Density Altitude Table
Pressure Conversion Table
Rainfall Depth Converter
Showalter Index Calculator
Station Pressure Calculator
Temperature Apparent Altitude Correction Calculator
Temperature Barometer Reading Correction Calculator
Tornado Information Table
UV Index EPA Calculator
Vapor Pressure Calculator
Virtual Temperature Calculator
Wind Chill Calculator
Wind Chill Table
Wind Speed Converter