Denmark’s met office DMI has issued a heatwave alert to parts of the capital region including the municipalities of Copenhagen, Lyngby-Taarbæk, Furesø, Høje Taastrup, and Ishøj.

A heatwave is defined as  three consecutive days on which the average of the highest temperatures each day exceeds 28 degrees Celsius.

Temperatures of just over 29 degrees Celsius were recorded in Frederiksberg on Wednesday DMI meteorologist Jesper Eriksen said to newswire Ritzau.

“We expect temperatures in the capital region over the next few days to reach similar levels – plus or minus one to two degrees,” he said.

“That means the heatwave we’re alerting is a very marginal one, but it is unusual for it to be this warm in early September. So I advise people to drink extra water and stay in the shade,” he said.

Heatwaves can cause discomfort and a risk of heatstroke.

Elderly people and small children are most at risk, as are people exposed to dehydration, intense exercise or physical labour.

DMI uses three categories of weather alert, with category 3 the most dangerous.

READ ALSO: What do Denmark’s weather warnings actually mean?

The current heatwave alert is category 2 or “hazardous” weather (farligt vejr in Danish), meaning the weather can affect your surroundings and outdoor activities.

Copenhagen will not be the only part of Denmark to feel the early September heat, with temperatures elsewhere in the country ranging between 22 and 27 degrees Celsius.

“This is heat that has locked itself over a large part of Europe, with Denmark situated in a warm air pocket,” Eriksen explained.

“Our best guess is that the hot weather will continue until Sunday, so we might extend the alert. But next week will bring a shift to more classic autumn weather with rain, showers, and falling temperatures,” he said.