American Red Cross
Map, Weather & Hazard Catalogs

Weather Calculators


Current Time Conversion

Current Time   (based on your computer's time):   UTC
  Local
Click for a Time Conversion Chart (PDF)

Temperature Conversion

Enter a number then click on the appropriate number to see the result.
Fahrenheit (oF)
Celsius (oC)
Wind Chill/Temperature Index Calculation in degrees Fahrenheit

Enter in the air temperature ( Tair ) in degrees Fahrenheit and wind speed in miles per hour ( mph ), then click on the Calculate WC to compute the windchill ( WC ).
Tairo F mph

Wind Chill / Temperature Index Calculators

Wind Chill/Temperature Index Calculation in degrees Celsius

Enter in the air temperature ( Tair ) in degrees Celsius and wind speed in miles per hour, then click on the Calculate WC to compute the windchill ( WC ).
Tair o C mph

Relative Humidity Calculators

Relative Humidity Calculation using degrees Fahrenheit

Enter in the air temperature ( Tair ) and dew point temperature ( Tdp) in degrees Fahrenheit ( oF ) then click on the Calculate RH to compute the relative humidity ( RH ).
Tair ( o F ) Tdp ( o F ) RH
Tair
Tdp
Relative Humidity Calculation using degrees Celsius

Enter in the air temperature ( Tair ) and dew point temperature ( Tdp) in degrees Celsius ( oF ) then click on the Calculate RH to compute the relative humidity ( RH ).
Tair ( o C ) Tdp ( o C ) RH
Tair
Tdp

Heat Index Calculation

Valid entries are, air temperatures greater than 80 °F ( 27 °C ), dew point temperatures greater than 65 °F ( 12 °C ), and relative humidities higher than 40 percent.
in Celsius

Enter in the air temperature ( Tair ) and the dew point temperature ( Tdp ) in degrees Celsius, then click on the Calculate HI to compute the heat index ( HI).
Tair in °C Tdp in °C RH =
in Fahrenheit

Enter in the air temperature ( Tair ) the dew point temperature ( Tdp ) in degrees Fahrenheit, then click on the Calculate HI to compute the heat index ( HI).
Tair in °F Tdp in °F RH =
in Celsius

Enter in the air temperature ( Tair ) in degrees Celsius and relative humidity ( RH ) in percent ( without the % sign ), then click on the Calculate HI to compute the heat index ( HI ).
Tair in °C RH Tdp =
in Fahrenheit

Enter in the air temperature ( Tair ) in degrees Fahrenheit and relative humidity ( RH ) in percent ( without the % sign ), then click on the Calculate HI to compute the heat index ( HI ).
Tair in °F RH Tdp =

Wind Speed Conversion

Enter a wind speed that you wouldlike to convert:
 Input-> Output:
mph mph
knots knots
m/s m/s
ft/s ft/s
km/h km/h


Storm Distance Calculator

Enter the latitude and longitude of a storm and your city (or any two points) to find the distance between them.

City Storm Distance
Lat: oN
Lon: oW
Lat: oN
Lon: oW
Miles