Convert Weather Temperatures from Fahrenheit to Celsius

Direct answer

Convert a weather temperature by subtracting 32 from Fahrenheit and multiplying by 5/9.

For example, a forecast high of 77°F converts to:

Use the Fahrenheit to Celsius Converter for any current or forecast temperature.

Common weather temperatures in both scales

These descriptions are general. Comfort and risk also depend on humidity, wind, sunlight, clothing, activity, health, and local conditions.

Example: convert a 45°F forecast

A weather service may round this to 7°C.

Example: convert a 72°F forecast

Rounded to the nearest whole degree, this is 22°C.

Example: convert a 100°F forecast

This represents very hot outdoor conditions, but the practical effect depends strongly on humidity, shade, wind, and exposure.

Understanding the freezing point

Water freezes at approximately 32°F or 0°C under standard reference conditions. Forecast temperatures close to this point can be important for ice, frost, precipitation type, and road conditions.

• 23°F = -5°C;
• 28.4°F = -2°C;
• 30.2°F = -1°C;
• 32°F = 0°C;
• 33.8°F = 1°C;
• 35.6°F = 2°C.

Surface temperatures can differ from reported air temperatures, so a converted air reading alone does not determine whether ice will form.

Converting forecast highs and lows

Convert the daily high and low separately. Do not average the two Fahrenheit values and assume the result represents both conditions.

Example forecast

A weather display may round this to a high of 28°C and a low of 16°C.

Converting hourly weather readings

Hourly forecasts often contain small temperature changes. Convert each hourly reading rather than applying one conversion to the entire range.

Air temperature versus feels-like temperature

Weather reports may show both the measured air temperature and a feels-like value. The feels-like value may incorporate humidity, wind, sunlight, or other factors depending on the weather service.

Convert each reported value independently. A forecast might show:

The conversion changes only the unit. It does not calculate the heat index, wind chill, or another derived weather measure.

Wind chill temperatures

Wind chill is a derived value intended to describe how cold conditions may feel on exposed skin. A wind chill reported in Fahrenheit can be converted with the same temperature formula.

Example: convert a wind chill of -10°F

Converting the stated wind-chill value does not recalculate it from wind speed and air temperature.

Weather conversion for international travel

Travelers may need to interpret forecasts shown in an unfamiliar temperature scale. Memorizing several benchmark values can make this easier:

• 32°F = 0°C;
• 50°F = 10°C;
• 59°F = 15°C;
• 68°F = 20°C;
• 77°F = 25°C;
• 86°F = 30°C;
• 95°F = 35°C.

These reference points make it easier to estimate nearby temperatures without converting every value precisely.

Quick mental weather conversion

For a quick estimate, subtract 30 and divide by 2.

Example: estimate 80°F

The exact value is approximately 26.67°C. The shortcut is useful for deciding what conditions may feel like, but exact values should be used where small differences matter.

Rounding weather temperatures

Forecasts often use whole degrees because weather measurements and predictions already contain uncertainty. A calculated value of 21.111111°C may therefore be displayed as 21°C.

When comparing forecasts from different services, small differences may result from:

• rounding;
• observation location;
• forecast model;
• update time;
• elevation;
• the definition of the displayed value.

Common weather conversion mistakes

Assuming 70°F equals exactly 20°C

The mental estimate gives 20°C, but the exact result is approximately 21.11°C.

Confusing air temperature and feels-like temperature

These are different reported values and should be converted separately.

Ignoring negative signs

Cold-weather forecasts can contain negative Fahrenheit or Celsius values. Preserve the sign during conversion.

Assuming the conversion predicts conditions

Unit conversion does not determine precipitation, ice, humidity, wind, or safety.

Using an estimate near important thresholds

Use the exact formula when comparing temperatures near freezing or another threshold.

Related Fahrenheit to Celsius guides

Frequently asked questions