Why is WNA only applied when weather is 3% warmer or colder than normal?

WNA is not applied to customer bills when weather is not 3% warmer or colder than normal because weather conditions didn’t significantly change how much energy was needed for heat. This 3% range is used to account for small fluctuations in weather and broaden what is considered normal weather by adjusting the Normal Heating Degree Days. The Actual Heating Degree Days are compared to this range to determine if WNA is applied to the bill.

• If the Actual Heating Degree Days are within the range, WNA is not applied because the weather was close to normal.
• If the Actual Heating Degree Days are higher than the range, a WNA credit is applied to the bill, because it was colder than normal.
• If the Actual Heating Degree Days fall below the range, a WNA charge is applied to the bill, because it was warmer than normal.

Customers can visit the Weather Normalization Adjustment page to learn more about the calculation.