Originally Posted by
Moelman 
so I know what it's like outside when I see the temp in C, but when people ask me "so what's that in F" I don't know the conversion.
The equation is F = (C*1.8)+32, but being a pilot, we use the weather reported in Celsius as well so if you're looking for a quick "rule of thumb" conversion just double the temp. in Celsius and add 28-30 and you should be relatively close.
e.g. C=40º
F=(40*1.8)+32 ---> 72+32 = 104
RoT--> F= 2*40 = 80 + 28-30 = 108-110, so you can get pretty close
Pilots use some weird math, worldwide we use Celsius for temperature, but for some reason, the ceilings (start of clouds) as well as Flight Levels (commonly flown IFR altitudes above 18,000 ft.) are reported in feet, and visibility is reported in statute miles or feet. Airspeed is reported in knots (nautical miles per hour) or Mach (relative to speed of sound). However if you fly in Russia all that is thrown out the window because they use their own system

.
Anyway, back to the topic at hand, to keep cool you could try wearing light colored clothing so that you don't absorb as much direct energy from the light of the sun