Monthly average of heating degree days in the United Kingdom 2014-2023

The greatest number of heating degree days (HDDs) in the United Kingdom is usually recorded in January and February of each year. In 2023, there were 10.2 HDDs in January, which was a slight decrease from the previous year. The highest number of HDDs during the period in consideration was recorded in February 2018, at 12.4 days. The following year, this figure dropped to some 8.6 HDDs.

Heating homes

Heating degree days are defined as days in which the average temperature is less than 15.5 degrees Celsius. They are used to help measure the demand for energy required to heat buildings. In the United Kingdom, the most common way to heat properties is by far gas central heating.

Cold winters

In January 2023, the average temperature in the UK dropped to just 2.9 degrees Celsius. This was the lowest average monthly temperature recorded since January 2021. That same month, there were 10.7 air frost days across the country, slightly up from 10.2 air frost days recorded in the same month of the previous year. Air frost days are when the minimum air temperature falls below zero degrees Celsius.