The Netherlands has just had its fourth warmest summer since records began in 1901, with two short heatwaves, plenty of sunshine and a persistent rainfall shortage, the KNMI weather bureau said on Monday.

Average temperatures reached 18.5°, a level that would have been almost unheard of a century ago but which now occurs roughly every two years, the KNMI said.

The warmth came not from prolonged extremes, but from the absence of cool days. June was the second warmest on record, while July and August both featured brief hot spells that pushed temperatures above 35°. The highest reading of the summer was 39° in made in Beek in Limburg province on July 2.

Rainfall was well below normal, with 155 millimetres over the three months, compared with an average of 224 millimetres. Because most of it fell during localised downpours, the differences were large. The south-west was extremely dry, while the north-east was close to average, the KNMI said.

By the end of August, the national rainfall deficit stood at 265 millimetres, placing this year among the driest 5% since 1901. There was also plenty of sunshine, with 750 hours compared with the usual 641, thanks mainly to June and August.

The KNMI said the pattern matches the changing climate: warmer, sunnier summers with erratic rain. “A summer like this, which is now common, would have been extraordinarily rare in the early 20th century,” the institute said.

As September begins, the recent unsettled conditions are set to continue, weather bureau Weeronline said in its weekly forecast.

The first day of the meteorological autumn will bring showers in the east, clearing later with some sunshine. Temperatures will reach around 22°.

For most of the week, the outlook remains changeable with daily showers, a moderate south-westerly wind and highs of 21° to 23°, which are on the warm side for early September. Wednesday and Thursday look to be the wettest, Weeronline said.

Towards the weekend, conditions should improve, with more sunshine and temperatures rising to 24°, possibly warmer in the south.

The KNMI’s long-term forecast sees the mixed conditions continuing well into the month.