I could not find a lot on this. Even when I tried various different combinations of words it was mostly on winter survival. When I limited my search to not include winter, there was very little available.

Most of what I found is for seniors in a heat wave. Not exactly useful discussion for how to survive five months in the summer without electricity. (Yes, we have 5 months of summer in Houston.)

I did find Maricopa’s Desert Awareness manual. It has some good stuff.

Here’s what they recommended for a personal survival kit:

Essential
Metal signal mirror
Whistle
Pocket knife
Flint and steel
Small candle
Cigarette paper book
Small pencil
Small magnet compass
Waterproof matches
Dental floss (100 yd)
1 qt canteen with water
Desirable
Band-aids
Bright colored balloons
Iodine tablets
Canteen cup
Waterproof match case
Map of area
Duct Tape
Bandanna
Useful
1 sq yd nylon or chiffon, brightly colored
4 Quarters (What the heck? So you can phone home?)
Hard Candy
Heavy Duty Aluminum Foil
Small fish hook
Salt
Tweezers
Razor blade
Heavy plastic bags for use as canteens
necessary, follow these rules: AVOID plants with milky sap. AVOID all
red beans. If possible, boil plants which are questionable. Test a
cooked plant by holding a small quantity in the mouth for a few
moments. If the taste is disagreeable (very bitter, nauseating, burning),
do not eat it.

POISONOUS CREATURES
Poncho or sheets of plastic
Needle with large eye
Cobbler’s linen thread (1 Yd)
Light picture cord (snare wire)
Comb
Snake bite kit
Bar of soap (small)
Woodman’s saw
Knife sharpening device
Survival guide (I am fairly sure this would be VERY useful for most Americans.)

Their suggestions are common sense, but useful.
Avoid stressful activities during the hot season.
Limit activities to cooler times of day. (This is probably where the two hour siesta came from.)
Keep pace slow and carry light loads.
Wear suitable clothing.

Operational Manual from the government
DO NOT eat food without water. (Maricopa mentioned that too.)

The operational manual would probably be useful for Apocalypse Man scenarios. There is also basic useful information in there.