Weather Calculators
Air Quality Index Calculator
Convert a PM2.5 concentration reading into its EPA Air Quality Index value and health category using the official breakpoint table.
Barometric Pressure Calculator
Convert between sea-level pressure and pressure at altitude, or find the sea-level equivalent of a station pressure reading, using the standard barometric formula.
Cloud Base Height Calculator
Estimate cloud base height above ground level using the temperature-dew point spread method, a standard aviation weather rule of thumb.
Dew Point Calculator
Calculate dew point in Celsius and Fahrenheit from air temperature and relative humidity using the Magnus formula approximation.
Frost Point Calculator
Estimate frost point, the sub-freezing equivalent of dew point, from a given dew point temperature below 0┬░C.
Growing Degree Days Calculator
Calculate Growing Degree Days (GDD) for a single day based on high/low temperatures and crop base temperature.
Heat Index Calculator
Calculate the heat index feels-like temperature from air temperature and relative humidity using NOAA's official Rothfusz regression formula.
Heating Degree Days Calculator
Calculate Heating Degree Days (HDD) for a single day based on high/low temperatures, a standard energy analysis metric.
Humidity Calculator
Calculate relative humidity from air temperature and dew point, or directly from actual and saturation vapor pressure readings, using the Magnus approximation.
Hurricane Category Calculator
Determine hurricane category based on sustained wind speed using the Saffir-Simpson Hurricane Wind Scale.
Lightning Distance Calculator
Estimate how far away a lightning strike occurred using the classic flash-to-bang counting method.
Rainfall Accumulation Calculator
Add up a list of comma-separated rainfall readings into a total accumulation and average per period, in inches or millimeters.
Sea Level Pressure Adjustment Calculator
Convert raw station atmospheric pressure to sea-level-equivalent pressure based on station elevation.
Snow Day Calculator
Get a fun weighted snow day probability score from expected snowfall, temperature, wind speed, and day of the week. For entertainment only.
Solar Noon Time Calculator
Calculate the approximate clock time of true solar noon based on longitude, timezone standard meridian, and equation of time.
Storm Surge Calculator
Estimate storm surge height from central pressure and sustained wind speed using a simplified inverse barometer and wind setup model, for educational use.
Tornado EF Scale Calculator
Look up the Enhanced Fujita (EF) tornado rating based on estimated wind speed.
UV Index Calculator
Convert a UV Index reading into its EPA exposure category, protection recommendation, and approximate time for unprotected skin to begin burning.
Wind Chill Calculator
Calculate wind chill temperature from air temperature and wind speed using the National Weather Service's official formula, valid at or below 50 degrees F.
Wind Speed Unit Converter Calculator
Convert wind speed between mph, knots, km/h, and m/s, the four most common wind speed units used worldwide.
The Temperature on the Thermometer Is Not the Whole Story
What weather actually feels like on skin depends on more than the air temperature alone — humidity and wind both shift how conditions are perceived, sometimes dramatically. These ten calculators cover that "feels like" math alongside standard weather measurements.
Popular Weather Calculators
- UV Index Calculator — estimates UV exposure risk level for sun safety planning.
- Air Quality Index Calculator — converts pollutant concentration readings into the standard AQI scale.
- Dew Point Calculator — calculates the temperature at which air becomes saturated and condensation forms.
Related: Environmental Calculators, Travel Calculators for trip planning around conditions.