I haven't been complaining about the heat, and for you in the SW what we have probably doesn't seem very hot. Yesterday I tried to ride in 98 degree temps that was somewhat humid...

Two other times this summer I've ridden in >95 temps and every time I've had the same results - nausea and, last night, a headache I ate more than an hour before heading out, had water and shot blocks for electrolytes with me. The LAST time I was able to wait out the nausea and was fine after the first 45 minutes. Last night was the worse of all, the nausea just kept getting worse, with the headache, until I just gave in and slowly rode home.

Once home I had another huge glass of water, did my normal post-ride stretches, and lay on the carpet for about 5 minutes. The nausea and headache left as soon as my body cooled off.

Should this be expected for riding in 98-99 degree temps? Am I just a wimp? It is frustrating, because it is supposed to be just as hot today, and the area where my favorite mountain bike trail are located is supposed to reach 100 degrees tomorrow