A cold snap will spread across Europe from the weekend, testing the region’s energy systems for the first time this winter.

Helsinki is forecast to experience lows of -11.5C for four consecutive days from Saturday, while other Nordic capitals also freeze, according to Maxar Technologies Inc. The cold will also envelop Germany and the UK, with temperatures in London expected to reach as low as zero degrees on Saturday.

“Wintry showers, and strong winds are likely into northern and eastern areas, with the risk of overnight frosts increasing through the weekend,” the UK’s Met Office said.

A total of 80.3 heating-degree days are forecast in the six to 10 day period for Europe, above the 10-year average, according to Maxar.

At the same, time, Germany’s wind turbines are likely to produce near-record levels of power later this week.

Read More: German Power Market Braced for Near-Record Wind Output

Output from turbines is expected to reach 50.08 gigawatts at 6 p.m. on Thursday, according to ECMWF data compiled by Bloomberg. That’s just shy of a record 50.8 gigawatts of power set in January, according to the European Energy Exchange AG.