When temperatures soar, it’s common to see electric bills rise. Many people assume it’s because our electric rates have increased, but that’s not the reason.

The biggest factor is something called Cooling Degree Days — a measurement that helps explain how much air conditioning your home needs.

A cooling degree day is recorded whenever the average outdoor temperature is above 65 degrees. The hotter it gets, the more cooling degree days accumulate. More cooling degree days mean your air conditioner runs longer and works harder to keep your home comfortable.

For example, if the average temperature for the day is 85 degrees, that’s 20 cooling degree days. A month with several days in the 90s can result in hundreds more cooling degree days than a milder summer, causing your air conditioner to use significantly more electricity.

Even if your rate stays exactly the same, using more electricity naturally results in a higher bill.

Think of it like filling your gas tank. If the price per gallon doesn’t change but you drive twice as many miles, you will still spend more on fuel. The same principle applies to electricity. The rate may remain unchanged, but increased energy use leads to a larger bill. 

Factors that increase summer use

Hot weather isn’t the only reason electric use climbs during the summer. Your home’s energy consumption can also increase because of:

• Longer air conditioner run times during heat waves.
• High humidity, making cooling systems work harder.
• More people at home during the day with summer break or vacations.
• Pool pumps, dehumidifiers, and irrigation systems running more frequently.
• Older or less efficient air conditioning equipment.

Keep cooling costs under control

While no one can control the weather, there are ways to reduce energy use:

• Set your thermostat a few degrees higher when you’re not home.
• Replace dirty HVAC filters monthly during heavy use.
• Keep blinds and curtains closed during the hottest part of the day.
• Use ceiling fans to help circulate cool air.
• Seal air leaks around windows and doors.
• Schedule annual maintenance for your air conditioner to keep it operating efficiently.

The bottom line

When your summer bill is higher, it’s often a reflection of increased electricity use — not higher electric rates. Cooling degree days help explain why two summers can produce very different bills, even when the cost of electricity hasn’t changed.

Understanding how weather affects your energy use can help you better manage your home’s comfort and your monthly electric bill.