Mercury hits 15 °C mark: first official mild spring day of the year confirmed

The Netherlands is experiencing its first official mild spring day of 2026, with temperatures in De Bilt exceeding 15 °C, meeting the meteorological criteria for a genuine spring day.

In the Netherlands, a day is considered an “official spring day” if the maximum temperature at De Bilt, the reference weather station for the Royal Netherlands Meteorological Institute (KNMI), reaches 15 °C or more.

Around 1:20 P.M. in De Bilt, temperatures reached 15.1 °C, officially signifying the first mild spring day. In southern regions like Maastricht, the mercury climbed to roughly 18.2 °C, with locally even higher temperatures possible later in the afternoon.

The 15 °C threshold serves as a meteorological indicator for the onset of spring-like conditions, separate from calendar or astronomical events like the March 20 spring equinox.

On average, the first official spring day in De Bilt falls around March 10. This year, it has arrived over two weeks early. By way of comparison, past years have seen the first mild day arrive in February or even January. In 2023, it occurred on January 1, and in 2024 on February 15, although the weather at the time felt less like spring despite the warm temperatures. The earliest official spring day ever recorded in De Bilt was on January 13, 1993.

Temperatures in some areas may locally rise to around 19 °C, approaching the current February 25 record of 19.1 °C, which was set in 2019, according to Weeronline meteorologists.

An “official” spring day, recorded in De Bilt, differs from a “local” spring day. In southern areas like Limburg, the 15 °C mark is often reached several days or even weeks before the central part of the country.