Belgium records warmest September to date

Belgium recorded its warmest September ever this year with an average daily temperature of 18.8°C and an average peak temperature of 24°C.

The record-breaking numbers are the highest recorded for September since records began in 1833.

“September 2023 was an absolute record month in terms of temperature,” the Royal Meteorological institute (RMI) said.

“The average temperature clocked in at 18.8°C, while normally it’s 15.2°C. The previous record, 18.4°C, dated from 2006. We’re talking about measurements since 1833.”

The record for the average maximum temperature was beaten, with 24°C compared to the normal 19.5°C. The previous record with 23.4°C also dated from 2006.

“These records are worrying,” said VTM meteorologist David Dehenauw. “It’s clear evidence of global warming, a sign that the climate is changing. Earlier, we also had the warmest June ever.”

For the average minimum temperature (which has been measured since 1982), the absolute record from 1999 was equalled: 14.1°C on average, or 2.8°C warmer than normal.

For the first time since observations began, Uccle also saw a heat wave in the month of September.

There were no less than six tropical days (30°C or warmer) in September, compared to the normal average of 0.1 days. Previous records for the number of tropical days - two in September - were set in 1906, 1911, 1919, 1949 and 2020.

In terms of the number of summer days (25°C and warmer), the record of nine days from 2006 was equalled.

The RMI also noted that September 2023 was characterised by few days of precipitation and exceptional sunshine.

The Uccle station recorded 64.3mm of precipitation. While this is not much less than the norm of 65.3mm, it fell in Uccle over eight days instead of the normal two weeks.

The sun shone for a total of 194 hours and 8 minutes, compared to the norm of 154 hours and 28 minutes, and the number of cloudy to overcast days hit a new record low of just four.