For Belgium, 2017 was the fifth hottest year since 1833, tying with 1989 and 2015, the Royal Meteorological Institute, IRM, stated in its climate report for 2017. The average temperature in Uccle was 11.3°C (normal temperature: 10.5°C), which is abnormally high. Most monthly averages were normal, but June was exceptionally hot, March was very abnormally hot (a new record) while May and October were abnormally hot, according to the IRM.
The lowest temperature for 2017 (-17,4°C) was recorded on the 23rd of January in Elsenborn (Bütgenbach), while the hottest (36,2°C) was registered on the 22nd of June in Houyet.
The year 2017 was also characterized by lower-than-normal rainfall, to the chagrin of farmers, especially in Spring. The amount of rain registered at Uccle, 749.1 mm, was 15% lower than normal.
“Since November 2016, we had to wait in Uccle until the month of September this year to have a total monthly rainfall that was above normal,” the IRM noted. “April was very abnormally dry and October abnormally dry, while November was abnormally wet and December very abnormally wet.”
Despite an exceptionally dark month of December, annual sunlight was normal at Uccle. The sun shone for 1,559 hours and two minutes in 2017.
The average windspeed for the year was 3.4 metres per sec (m/sec) in Uccle, which is a “very abnormally low” value. The normal value is 3.7 m/sec.