Fahrenheit to Celsius
To convert Fahrenheit to Celsius, subtract 32 and divide by 1.8. Room temperature at 72 °F is 22.2 °C, a 350 °F oven is 176.7 °C, and 98.6 °F is 37 °C. The order matters: subtracting after dividing gives an answer that is wrong by about eighteen degrees.
How to convert °F to °C
Recipes are where this matters most, and where rounding is normal. American baking temperatures of 325, 350, 375 and 425 °F become 163, 177, 191 and 218 °C, which European recipes round to 160, 180, 190 and 220. A fan oven then wants about 20 °C less again, so a 350 °F recipe is 160 °C fan.
Questions
176.67 °C. Most recipes round it to 180 °C, or 160 °C in a fan oven.
It gets you close for weather: 72 °F gives 21 against a true 22.2. The error grows at the extremes, so do not bake with it.
Daniel Fahrenheit set zero at the temperature of a brine mixture and 96 at roughly body heat. The scale was later redefined against the freezing and boiling points of water, which is how 32 and 212 arrived.
Around 38 °C, which is 100.4 °F, is the usual clinical threshold. This converter is arithmetic and not medical advice.