Temperature measurements and units of measure. There are units but only F, C, and K are common.

• F = C(9/5) + 32 = Fahrenheit
• C = (F-32)5/9 = Celsius
• K = C + 273.15 = Kelvin. The official SI/metric unit of measure for temperature.
• R = F + 459.67 = Rankine.

I am fine with the English convention of saying "six degrees Celsius" or "six degrees Fahrenheit" or "six kelvins", but the convention of printing "6 °C" and "6 °F" but "6 K" is maddening! Hence I decree that on my site, I will write "6 C" or "6 F" or "6 K".

## Example Temperatures

I've listed these values as an exercise to help me get a feel for the relation between Celsius and Fahrenheit. The F temperatures are rounded to 0.1 F unless otherwise noted. The temperatures are fun ones and ones in weather forecasts in Chicago.

• -273.15 C = -459.67 F = 0 K = 0 R. Absolute zero.
• -50 C = -58.0 F.
• -45 C = -49.0 F.
• -40 C = -40.0 F. Exactly. Coincidence.
• -39 C = -38.2 F.
• -38.83 C = -37.89 F. Melting and freezing point of Mercury.
• -38 C = -36.4 F.
• -37 C = -34.6 F.
• -36 C = -32.8 F.
• -35 C = -31.0 F.
• -34 C = -29.2 F.
• -33 C = -27.4 F.
• -32 C = -25.6 F.
• -31 C = -23.8 F.
• -30 C = -22.0 F.
• -29 C = -20.2 F.
• -28 C = -18.4 F.
• -27 C = -16.6 F.
• -26 C = -14.8 F.
• -25 C = -13.0 F.
• -24 C = -11.2 F.
• -23 C = -9.4 F.
• -22 C = -7.6 F.
• -21 C = -5.8 F.
• -20 C = -4.0 F.
• -19 C = -2.2 F.
• -18 C = -0.4 F.
• -17.78 C = 0 F = 459.67 R. Exactly One story holds that Fahrenheit referenced this as the point where equal amounts of salt and water melt. Freezer refrigeration should be around this temperature.
• -17 C = 1.4 F.
• -16 C = 3.2 F.
• -15 C = 5.0 F.
• -14 C = 6.8 F.
• -13 C = 8.6 F.
• -12 C = 10.4 F.
• -11 C = 12.2 F.
• -10 C = 14.0 F.
• -09 C = 15.8 F.
• -08 C = 17.6 F.
• -07 C = 19.4 F.
• -06 C = 21.2 F.
• -05 C = 23.0 F.
• -04 C = 24.8 F.
• -03 C = 26.6 F.
• -02 C = 28.8 F.
• -01 C = 30.2 F.
• 00 C = 32.0 F = 273.15 K. Freezing point of water at 1 atm. Exactly. Meat refrigeration should be around this temperature.
• 01 C = 33.8 F.
• 02 C = 35.6 F.
• 03 C = 37.4 F.
• 04 C = 39.2 F.
• 05 C = 41.0 F. Regular refrigeration should be around this temperature.
• 06 C = 42.8 F.
• 07 C = 44.6 F. Milk should be kept below this temperature.
• 08 C = 46.4 F.
• 09 C = 48.2 F.
• 10 C = 50.0 F. Vegetable refrigeration should be this temperature.
• 11 C = 51.8 F.
• 12 C = 53.6 F.
• 13 C = 55.4 F.
• 14 C = 57.2 F.
• 15 C = 59.0 F.
• 16 C = 61.8 F
• 17 C = 62.6 F
• 18 C = 64.4 F
• 19 C = 66.2 F
• 20 C = 68.0 F. Common room temperature. Cold nerve receptors react to temperatures below this point. Common legal minimum temperature to be maintained by landlords
• 21 C = 69.8 F
• 22 C = 71.6 F
• 23 C = 73.4 F
• 24 C = 75.2 F
• 25 C = 77.0 F. Common room temperature. Common tropical fish tank temperature.
• 26 C = 78.8 F
• 27 C = 80.6 F
• 28 C = 82.4 F
• 29 C = 84.2 F
• 30 C = 86.0 F
• 31 C = 87.8 F
• 32 C = 89.6 F. Hot nerve receptors react to temperatures above this point.
• 33 C = 91.4 F
• 34 C = 93.2 F
• 35 C = 95.0 F
• 36 C = 96.8 F
• 37 C = 98.6 F. Common figure for human core temperature, although statistically it is actually 36.8±0.7 C = 98.2±1.3 F.
• 38 C = 100.4 F
• 39 C = 102.2 F
• 40 C = 104.0 F.
• 41 C = 105.8 F.
• 42 C = 107.6 F.
• 43 C = 109.4 F.
• 44 C = 111.2 F.
• 45 C = 113 F. Pain nerve receptors react to temperatures above this point.
• 46 C = 114.8 F.
• 47 C = 116.6 F.
• 48 C = 118.4 F.
• 49 C = 120.2 F.
• 50 C = 122.0 F. Mammalian muscle becomes rigid.
• 60 C = 140.0 F.
• 70 C = 158.0 F.
• 80 C = 176.0 F.
• 90 C = 194.0 F.
• 100 C = 212.0 F. Boiling point of water at 1 atm.
• 125 C = 257.0 F. Common baking temperature.
• 150 C = 302.0 F. Common baking temperature.
• 175 C = 347.0 F. Common baking temperature.
• 200 C = 392.0 F. Common baking temperature.
• 225 C = 437.0 F. Common baking temperature.
• 233 C = 451.4 F. The flash point or auto-ignition point of paper as made famous by Fahrenheit 451, a 1953 book by Ray Bradbury.
• 250 C = 482.0 F. Common baking temperature.
• 660.32 C = 1220.58 F = 933.47 K. Aluminum melts.
• 1668 C = 3034.4 F = 1941 K. Titanium melts.
• 3410 C = 6170 F = 3683 K. Tungsten melts. The highest melting point of any chemical element.
• 3642 C = 6588 F = 3915 K. Carbon sublimes.
• 5527 C = 9980.6 F = 5800 K. Surface of the sun.

Outside temperature: 40s dangerous, 30s hot, 20s nice, 10s cool, 0s freezing, -10s dangerous.

Page Modified: (Hand noted: ) (Auto noted: )