Yup, that's me out on my branch in the breeze.

I tend to agree with Irydyum about light tempertures. MH lights run hotter then HPS lights. I've measured the difference in 600w HPS vs MH and the MH bulb produces much more direct heat then an HPS. The reason is as Irydyum stated, for 600w energy in the MH bulb produces about 40,000 lumens of light, while the HPS converts 600w into 90,000 lumens. What does not get converted into lumens goes to extra heat. If you want to consider secondary heat generation, then the HPS will heat an object greater because it has more then twice the radiant energy then the MH. But the greater radiant heat produced is a product of simply more light energy then spectrial differences.

This can be seen better with say a T5 fluro tube. If you measure the heat output from an actinic white @ 420nm or abt 12,000K, a 6500K daylight tube and a 2,700K bloom tube, they all produce the same heat output even tho they are way different in Kelvin temps. According to FreeDaHerb this can not be, the 12,000K should be much hotter then the 2,700K tube. But in the real world it is not.

BTW, there is a nice cooling breeze on my branch and the view is awesome.