Warm spring weather brings sharp temperature swings across Norway

Norwegians are enjoying unusually warm spring temperatures in parts of southern Norway, but meteorologists warn of sharp drops and even snow as cold air moves in from the north, Dagbladet reports.

Temperatures reached 17°C in Trøndelag on Monday, with Bergen at 16.2°C and Oslo at 14.7°C. However, overnight lows in Oslo dipped to just 1.8°C, illustrating what meteorologists describe as a “typical spring phenomenon” with high day-night variation due to clear skies.

“It’s easy to be fooled now when you look out the window,” said Aslaug Skålevik Valved, duty meteorologist at the Norwegian Meteorological Institute. She noted that while southern regions like Østlandet and Vestlandet could see 17–18°C on Tuesday, northern Norway faces harsh conditions, including snow squalls in Finnmark and gale-force winds.

By Thursday, colder air will push southward, lowering snow lines and bringing sleet or snow to inland lowland areas in the west. Valved cautioned that drivers who have switched to summer tires may face hazardous conditions. Nighttime frost is also expected to return in many areas.

The shift follows a dissolving high-pressure system over southern Norway, replaced by cold northwesterly winds. Meteorologists have also expanded wildfire warnings due to dry conditions, now covering regions from Vestland to Nordland and southern Troms.

Meanwhile, Oslofjord is experiencing its third major algae bloom of the year—an unusually high frequency for mid-April. Researchers at the Norwegian Institute for Water Research (NIVA) report brown discoloration from Sandefjordsfjorden southward, though the exact algae species and its toxicity remain unidentified.

“We’ve never seen anything like this before,” said senior researcher Anette Engesmo, linking the blooms to extreme weather mixing water masses. While the previous bloom collapsed during Easter storms, the current event stretches toward Drøbak but has not yet affected inner fjord areas.