I left Ft. Sill in June. It was H-O-T! August, from what the DS said will be be even hotter with more humidity. It was close to 100 every day for the last week I was there ending 11 June 10. They said in July and August the temp is over almost 100 everyday.
Drink water... lots and lots of water; find shade often; the constant wind there, especially up on the ranges, helps keep you cool to a point. The breeze around the barracks feels like walking into a hair dryer when it blows, but on the ranges it is much cooler and refreshing. There is almost no natural shade on the ranges. Make sure you have sunscreen. Don't need to worry about bugspray except for ticks when you are out in the tall grass because most of the misquitos and flys cant fly in the wind there.
Watch out for scorpions, black widdows, and rattle snakes on the FOB if you go there.
If you can shop at the main PX, do so, the shoppette in the IET area is expensive and doesnt have much of a selection.
I dont know anything about the actual WTC course, I was just there for BCT this year.
Oh dear, I think I just had a minor anxiety attack.
I was there AUG-OCT and it was hot (112 roughly) but it is a dry heat so its like a constant blow dryer in the face; I preferred it to humidity. I didn't see ANY rattlesnakes or black widoes but a female in my platoon got stung my a scorpoin on her bum becuase it was at night and she didn't check with her flashlight before she went potty. I did see armadillos though and I'd never seen those before being from Michigan.
We didn't get to go to the main PX except for occasionally, I was good with the shopette. Hydrate ALL the time and the DS's will take care of the rest depending on the heat cat (which is usually 5), take care of your feet and you'll be fine.