When you need this

The United States uses Fahrenheit for weather. Almost everywhere else, from London to Tokyo to Mumbai, uses Celsius. So when an American coworker says "It's 80 out," and you think "80 degrees is impossible", you're both right: 80 Fahrenheit is about 27 Celsius, a warm summer day.

In conversation, people rarely say the scale. Americans say "It's 65 today" and mean Fahrenheit; a Canadian in Toronto says "It's 18 today" and means Celsius. When the two worlds meet, add the word: "65 Fahrenheit, so about 18 Celsius."

You don't need the exact formula for small talk. A rough rule works: to go from Celsius to Fahrenheit, double it and add 30. So 20 Celsius is about 70 Fahrenheit. To go back, take away 30 and halve it. It's off by a degree or two, and nobody at a bus stop will mind.

A few fixed points help most. 32 Fahrenheit is 0 Celsius, freezing. 50 is 10, a cool day. 70 is about 21, pleasant. 90 is about 32, hot. 100 Fahrenheit is about 38 Celsius, a very hot day. A normal body temperature is 98.6 Fahrenheit, which is 37 Celsius.

Phrases

the unit for temperature; "it's 70 degrees"

the scale used for weather in the US

the scale used in most other countries

casual American way to give the temperature outside

somewhere from 60 to 69 degrees

the warmest and coldest temperature of the day

the number is not exact

asking someone to change the number for you

a quick way to go from Celsius to Fahrenheit

a body temperature higher than normal

Say it out loud

Tap a sentence to hear it. Say it after the voice.

  6. "The forties" means 40 to 49 degrees Fahrenheit, cool but not freezing.

Practice · 3 min

Change the number and say it naturally. Temperature on the left, one natural line on the right.

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Say it today

Use it once in a real conversation before tomorrow. Out loud counts, even to yourself.