We can only speak of a heat wave when temperatues reach at least 25 degrees Celsius (77 Fahrenheit) for five consecutive days, while on three of these days this should be at least 30 Celsius. The heat wave ends on the day that the maximum temperature fails to reach 25 Celsius.
Today, weather presenters expect that the 30 degrees mark will be reached with ease, which will make it a new heat wave, the second this season. It's 12 years ago since we last had two heat waves in one season. Before 2006, this was also the case in 1995 and 1911.
The weather is expected to change on Wednesday or Thursday
The year 1947 still holds the all-time record with four heat waves, says weather presenter David Dehenauw. That year also had the longest heat wave on record, with 19 days. The figures go back to 1901. Our first heat wave this summer (13-27 July) lasted as many as 15 days.
This new heat wave is expected to last until Tuesday or Wednesday, as the weather will become more unstable in the middle of the week. Thursday should be a lot cooler and have the biggest chance of blustery showers. However, before that, Tuesday is expected to become blistering hot with temperatures of up to 35 Celsius (95 Fahrenheit).
"More tropical days, summer's days and warm days than in the past: climate change"
"We see that we are having more tropical days (+30 Celsius) and summer's days (+25 Celsius) than 50 or 100 years ago", says the VRT weather presenter Frank Deboosere. "We also have more warm days with temperatures of 20+. It's crystal clear: the human influence on the climate is a fact."