When I am out in the heat (lots of that out here in So. Cal.) with that Santa Anna wind, and lately humidity to boot, I up the water and electrolytes and ease off the ride, listening to my body and not my mind. If I feel thirsty, I blew it; I'm dehydrated already. So I drink like a drunken sailor. I find I can't take anything like bloks or a Cliff bar if I am feeling thirsty and there goes the ride. Two bottles, one with just water and the other with Cytomax or Gu to start, with electrolyte bloks when I run out of the electrolyte drink and have only water. Call me a 'packer' but I pack a banana, two Cliff bars, two pkgs of bloks, and an extra emergency pkg of bloks in the saddle bag.

Dress for the occasion. Good quality jersey with UPF rating, water/sweat rated sunblock and those sun sleeves (yes they really work) can all help your body cool. I also wear a white Head-Sweats under my helmet. I find my head really gets warm with the Sun beating down through the helmet holes, the Head-Sweats really helps reflect it and pouring a little water in the helmet and on to it helps cool me.

As for wind, there's no getting around it. We get Santa Anna winds out here that can gust from the NE/NW and feel like someone just grabbed your rear wheel and stuck your head in front of an open broiling oven. Bring your elbows in close to your body, pivot down as much as you comfortably can at the waist, move down to the drops, don't sit up like a sail. I spend quite a bit of time stretching and trying to stay flexible when off the bike for this reason. I need to be able to stay in the drops for long periods, for as long as I am riding into the wind. Anything you can do to lower your frontal mass and streamline will lower the energy you need to produce to move. This will also help in keeping you cool as you are not revving your engine as hard to produce forward motion into the wind. This may sound silly, but don't forget to breathe. I find if I am really grinding it out, I hold my breath when I get tense. More wasted energy. So I have to remind myself to lessen my death-grip on the bars, smooth out my peddling and drop into a lower gear, stop bouncing/weaving on the bike, lower my head, stop clenching my teeth, soften my facial muscles, breathe smoothly.

For sure, don't up the ride miles way beyond what you are used to on a hot humid windy day. Take it in increments and listen to your body.