Monthly HDD Tallies Across Europe Identify A “Climate Change” Signature for Winter 2023-24

Highlight: Another mild winter in Europe.

Fig. 1-2: Consensus of selected cities across East and West Europe monthly HDD observations (and March forecast) compared to the past 2 winter seasons and the 30-year/10-year normal.

Discussion: Another mild winter season across Europe as monthly heating degree day averages for West Europe were seasonably chilly in November and both West and East Europe in January while other months, especially February were prohibitively warm (Fig. 1-2). Compared to the past 2 winter seasons, winter 2023-24 featured a much warmer December, February, and March. The month of January observed some arctic air while at other times strong warming occurred. On average, January was colder than the past 2 winter seasons although still slightly milder than normal for West Europe and colder than normal for East Europe. The observed HDD monthly values are, in our view, a classic climate change pattern whereas the overall regime is very warm with a brief cold interruption (in January) causing a normally chilly mid-winter.