Planning my first tour, will be solo and in Southwest. Can July work or is it unreasonably hot?

Lately, it seems that anything outside of November through April can be really hot. Right now, at the beach in SoCal, it is 90*. A few miles inland it is about 105*.

If you are going to ride outside of those months, then I would suggest you prepare well. Wear light colors. My summer riding gear is white and silver with mesh panels. Invest in a cooling vest. Install a hydration pack into your gear and carry plenty of water. Stay hydrated. Get some shirts like the REI Sahara or the Columbia Tamiami so that you can keep yourself covered and cool when stopped. Get a boonie hat so you can cover when stopped. Carry a collapsible umbrella so that you can provide yourself shade in an emergency.

Plan on 9 hour days and no more. Milage doesn't matter but time does. I don't mean riding 9 hours, I mean 9 hours not in camp or motel. Be somewhat structured in your routing, with a well-planned route, rest stops, gas stops, and camping or motel. Eat sensibly, pay attention to blood sugar levels, get good protein, good hydration, and allow at least 8 hours for alcohol's effect to wear off before riding. If you get a headache or feel nauseous find shade, stop, and hydrate before you stroke out.

You can ride when it is hot and survive. I have ridden through Arizona in 115* heat for hours and have been in Death Valley area when temperatures were creeping over 120*. If you are prepared you can do it with a minimum of drama.

Riding in the southwest means you're going to be in desert areas, high and low. The high deserts can get every bit as hot as the low deserts, but you can find them quite a bit cooler in the evening. You'll need to prepare for that, too, in case there is a cold snap. I got snowed on one time in June.

Here in California, we have also had a lot of fires in the hot months. Back in '19 I was riding through areas that were still burning and in '20 I had to re-route far inland (with much higher temperatures) when Route 1 was on fire (again). The smoke and ash from Pacific coast fires (WA-OR-CA) can be carried to the west and may be irritating to your eyes and lungs. The only strategy that I have found for this is "Run away!".

If you already knew everything I just said, you're capable. If some of it was new, learn how to prepare.

On rare occasions I’ll disagree with PDW. This is one of them. Don’t delay your trip past July because out west, you get into why we call “fire season.” Plan to be heading home by the end of July. Even that might not be early enough. Otherwise, ditto what everyone else said. Since you’re an Eagle Scout, you know most of this stuff.

I’ll usually poke fun at women in Lulu Lemon spandex yoga pants carrying around plastic water bottles in suburbia, claiming they need to “hydrate!” Jeez, you can still find water fountains and if you’re really hard up, get water from a sink. No need to fill up the landfills with plastic disposable water bottles, while they drive an EV to advertise their environmental consciousness. But I will emphasize that you bring and drink LOTS of water in the areas you’ll be touring. You won’t feel yourself sweat, because the dessicating air will evaporate it away instantly (unlike, say, Chicago). If you’re not stopping to pee at least every four hours, and if it gets any darker than the normal pale yellow, then you’re not drinking enough water. Dehydration has lots of insidious effects. You can read about ‘em online.

And have a ton of fun!