TEMPERATURES

Generally express in figures, no space before or period after C or F; spell out the expressions "below zero" and "minus" except in conversions.  Use comma only with five digits or more:

When referring to temperature changes, spell out numerals one through nine. For example: the ocean will warm two degrees Celsius. 

In scientific articles usually express temperatures in degrees Celsius or in kelvin, with Fahrenheit in parentheses.  In a more informal context Fahrenheit is acceptable.  Do not use the term centigrade.

C is the abbreviation for Celsius, cap C, no space or period.  When writing out, use degrees with zero or values greater than one:

            23 degrees Celsius, zero degrees Celsius; minus 4°C or -4°C

F is the abbreviation for Fahrenheit:

            32°F (no spaces, no period); 0°C (32°F).

In a temperature written with a degree symbol, use a comma only with five digits or more.

Do not use degree or degree symbol with kelvin: 3K or 3 kelvins.

Be careful when converting from one scale to another to distinguish between an actual temperature and a range of degrees:

            For instance, a temperature of 32 degrees Fahrenheit is equivalent

            to a temperature of zero degrees Celsius, but a change of 32 degrees Fahrenheit

            (say, from 10° to 42°F) equals a change of 17.7 degrees Celsius

            (one degree C equals 1.8 degrees F).