Normal US heating degree day accumulations over the full heating season.

Scientific fields are awash in arcane jargon. The world of energy data is no different. One key term — degree days — is a measurement for comparing relative warmth and cold between years and among regions.

Specifically, a degree day is a unit, based upon temperature difference and time, used in estimating fuel consumption and specifying nominal annual heating and cooling loads of a building. When the mean temperature is less than 65 degrees Fahrenheit, the heating degree days are equal to the total number of hours that temperature is less than 65 degrees Fahrenheit for an entire year.

Degree Days — Four Ways
In the world of energy data a degree day is not enough. There are four other ways degree days can be used:

• heating,
• cooling,
• normals and
• population-weighted.

During the 2003/2004 season, Nebraska's heating degree days totaled 6179 or 346 degree days less than the heating degree day normal. This indicates Nebraska's winter was 5% warmer than normal. In 2004, Nebraska's cooling degree days totaled 812 or 196 degree days less than the cooling degree day normal. This indicates Nebraska's summer was 19% cooler than normal.

Degree Day Map. Click a city closest to you for your degree days.

Degree Day Normals cover a 30-year period of records and are updated through the end of each decade. In the United States, the National Oceanic and Atmospheric Administration’s National Climatic Data Center has computed normals for 1921-50, 1931-60, 1941-70, 1951-80, 1961-90, and 1971-2000. The current or official 30-year period used for degree-day normals is 1971-2000. Normals help to describe the average weather of a location and are best used as a base to which the weather during the following decade can be compared.

Nebraska's heating degree day normal for a year is 6525 and cooling degree day normal for a year is 1008. In a year with normal weather, Nebraskans will heat their homes and businesses 6525 degree days and cool their homes and businesses 1008 degree days. In comparison, Hawaii (a hot weather state) has 20 heating degree days and 3002 cooling degree days, and Colorado (a cold weather state) has 7410 heating degree days and 273 cooling degree days.