A heatwave is a period of unusually hot weather that typically lasts 3 days or more. A heatwave can happen anytime during the year. They are normally associated during the summer months but they can take place during the fall, winter, and spring. A heatwave is measured to the usual weather in the area and relative to normal temperatures for the season.
For Central PA, a heatwave is normally 3 or more days with 90 degree temperatures..
When under a heatwave keep cool and stay hydrated. Check-in on family and neighbors to make sure they are doing OK and keep an eye on your pets.