2025 is already setting weather records as February tied for the hottest February in Phoenix on record, according to the National Weather Service .

Spring arrived early with above-normal temperatures throughout the month. The average temperature in February was 66 degrees, a 6.1-degree departure from normal at 59.9 degrees. This year tied with 1991 for the hottest February on record.

“We were just sitting under a ridge of high pressure, allowing temperatures to keep rising and rising,” said Alicia Ryan, a meteorologist for the National Weather Service office in Phoenix.

High-pressure systems can cause warmer temperatures as air compresses, and there are typically fewer clouds, allowing more direct sunlight to reach the ground.

This winter’s La Niña also could have played a role. La Niña is a climatological pattern stemming from the Pacific Ocean that tends to create drier and warmer conditions than usual in the Southwest.

During a La Niña cycle, cooler temperatures in the Pacific Ocean trigger a chain reaction of weather events around the world, affecting temperature and precipitation.

While February was warmer than normal, Phoenix will cool slightly this week as two low-pressure systems will move through the region.

The high temperatures in the beginning and end of the week will be in the 60s and as low as the 40s overnight. There will be a slight warm-up midweek between systems.

“Now we’re seeing that ridge pattern breaking, and that’s why we’re getting a little bit of the cooler temperatures,” Ryan said.

Hayleigh Evans writes about extreme weather and related topics for The Arizona Republic and azcentral.com . Email her with story tips at .