Belgium has a temperate maritime climate characterized by moderate temperatures, prevailing southerly to westerly winds, abundant cloud cover and frequent precipitation. Summers are relatively cool and humid and winters relatively mild and rainy. Observed temperatures have revealed a significant upward trend since the end of the 19th century. In recent years, the temperature shows a constant increase of 0.4 °C per decade. Precipitation in Belgium reveals high variability over time, with a slow, but significant, rising trend. Significant increase in annual accumulations have been observed (about 7%), as well as winter and spring accumulations (approximately 15%). The number of days with heavy precipitation and the maximum amount of precipitation in 5, 10 and 15 days have also increased significantly.
- The annual average temperature in Uccle is almost 2.4 °C higher in 2016 than it was in the pre-industrial period. The average temperature in all four seasons has risen, with the greatest rise being recorded in spring.
- Belgium has a very high variability in precipitation.
- The annual amount of precipitation in Uccle shows a slow, but significant, rising trend. Between 1833 and the beginning of the 21st century, there was a significant increase in annual accumulations (about 7%), as well as winter and spring accumulations (approximately 15%).