100 F is about 37.78 C. Using the formula C = (F - 32) x 5/9: 100 minus 32 is 68, and 68 x 5/9 = 37.777..., which rounds to 37.78. A free converter gives the same answer instantly for any temperature.
Start with 100 F. Subtract 32 to get 68. Multiply by 5 to get 340, then divide by 9 to get 37.777 repeating, or 37.78 C rounded to two decimals. The repeating decimal is normal; many Fahrenheit values do not land on a clean Celsius number.
As a body reading, 100 F sits above the traditional 98.6 F (37 C) average. The threshold many medical sources use for a fever is 100.4 F, which converts to exactly 38 C. As weather, 100 F is a very hot day at 37.8 C. Same number, very different feelings depending on where the thermometer is.
It is above the traditional 98.6 F average, and the commonly used fever threshold is 100.4 F, which is exactly 38 C. For anything health related, follow medical advice rather than a converter.
212 F, the boiling point of water at sea level.
About 37.8 C, which is a very hot day in most climates.