Heat precautions from the American Red Cross

Precautions include

Before the heat:

-- Know increased demand for power and air conditioning can cause a power outage. Have a flashlight and cash on hand. Plan out where to go (like a library) if it is hot and you have no air conditioning.
- Make sure your pets have access to shade and water.

During a heat event:

-- NEVER leave children or pets alone in a car, even with the windows cracked open.
-- Drink plenty of water
-- Postpone outdoor games in the sun
-- Slow down and avoid strenuous exercise at the hottest time of the day.
-- And help us with our mission: Check on neighbors and pets to see how they're coping with the heat.

Also note: "Excessive Heat" is described as a state when temperatures are 10 degrees or more above the average high temperature for the region during summer months, last for a long period of time and occur with high humidity as well.

More at http://www.redcross.org/www-files/Documents/pdf/Preparedness/checklists/HeatWave.pdf