Temps? How to measure?

So I know what the temp should be... What I don't know is where and how to measure. I have a digital remote sensor. Temps @ top of pots are 88h out in open and 78-80 if i sheild sensor ( ambient ) all plants (clones ) are about 6" right now. So, Do I measure out in direct light, or do I want an ambient temp? I will be raising sensor to plant top height.

you want the ambient temp at the top of the plant canopy

Thank you Desertrat. Those direct light temps are a lil high! lol thanks again.and a lil rep 4 ya!

you're welcome. the temps are quoted as ambient in the growfaq and stickies but most people don;t the difference between radient heat and ambient heat. + rep back to you

I must admit I never noticed anything about it in FAQ and it was/is down When I finally figured that I must be measuring wrong. 400w 20" away reading 96' lol Went out and bought a 6" cool tube and a 453 CFM inline (Grow is in a 1215 Cubic foot bedroom) vented the bedroom door w/ a 12"x6"x6" register and a lil duct work to make it light proof, to allow cool (78') House air into room. after this was all done, still read 87'. So I got to thinking and apparently I was doing it wrong cuz ambient is @ 78' @ canopy now that I have sensor shaded.