What is the best time to play pickleball in Phoenix in summer?

The National Weather Service Phoenix office says the coolest part of the day is usually between 4 and 7 a.m. The City of Phoenix also recommends using indoor facilities when possible during extreme heat.

How much water should I drink playing pickleball in the heat?

NWS Phoenix advises 1 to 2 liters of water per hour spent outdoors, and warns your body can lose up to 4 liters per hour during strenuous activity. Drink even if you don't feel thirsty.

When should I stop playing in the heat?

The CDC says to stop all activity and get to a cool place if you feel faint or weak, and to seek medical care right away if you or a partner has symptoms of heat-related illness.

Playing Pickleball in Phoenix in Summer: A Heat Safety Guide

This is general safety information from public health and weather agencies, not medical advice.

When to play

Go early. NWS Phoenix says that if you must do strenuous activity, do it during the coolest part of the day, “usually in the morning between 4:00 a.m. and 7:00 a.m.”
Move indoors when you can. During extreme heat, the City of Phoenix recommends using indoor facilities that accommodate physical activity.
Shorten sessions. The City recommends limiting the length of outdoor activity, pacing yourself, and taking frequent breaks.
Watch the warnings. The National Weather Service issues an Extreme Heat Warning when heat risk is high or very high. On those days, the City of Phoenix says it’s best to stay indoors. NWS also publishes a seven-day HeatRisk forecast.

Water and gear

Drink 1 to 2 liters per hour outdoors. That is NWS Phoenix’s guidance. It also warns the body can lose up to 4 liters of water per hour during strenuous activity, so carry water and drink before you feel thirsty.
Skip alcohol and sugary drinks. NWS, the City of Phoenix, and the Arizona Department of Health Services all advise against them in the heat.
Don’t take salt tablets unless a doctor tells you to (NWS).
Dress light. Wear lightweight, loose, light-colored clothing and a wide-brimmed hat, and use sunscreen.
Cool down afterward in the shade if possible (City of Phoenix).

Know when to stop

The CDC says people who exercise on hot days are more likely to become dehydrated and get heat-related illness. Its guidance for athletes:

If you feel faint or weak, stop all activity and get to a cool place.
Muscle cramping may be an early sign of heat-related illness.
Watch your partner, and have them watch you.
Seek medical care immediately for symptoms of heat-related illness. For an emergency, call 911.

The Arizona Department of Health Services notes that people who work or exercise outdoors, adults 65 and older, and people with chronic medical conditions are among the most vulnerable to heat.

Editor note for Ben: the next step is the first-hand part that makes this page worth citing: a list of Phoenix-area indoor and shaded courts, their summer hours, and early-morning open play. Please supply or confirm these from your own knowledge; we have not listed any courts we could not verify.