DES MOINES, Iowa – With the first near-freezing temperatures of the season happening this week, our minds are looking more toward winter. So, what kind of winter can we expect in Iowa this season?

Winter conditions are largely driven by broader patterns, such as ocean temperatures near the equator in the Pacific. This circulation is known as the El Niño Southern Oscillation. When trade winds over the equator strengthen, thunderstorms are pushed farther west along the equator and waters in the Pacific along South America become cooler. This setup is known as La Niña.

This year, we are entering a weak La Niña year. Typically, cooler conditions set up in the northern United States with wet weather in the Pacific Northwest and in the Great Lakes regions. The southern United States usually ends up warmer and drier.

The strength of the La Niña pattern can also dictate the amount of precipitation in central Iowa. A weaker La Niña pattern has been tied to more snow in central Iowa, while stronger La Niñas can lead to less snow.

That brings us to this year’s winter outlook. The La Niña signal will mean a higher likelihood for cooler-than-normal conditions across the northern United States, including in the northwestern half of Iowa. This will be due to a more amplified jet stream and the probability of more cold air outbreaks, especially late in the winter.

This pattern will also mean an increased chance for a wetter than normal winter. Much of this will depend on the storm tracks that set up over the winter, and a slight deviation in the storm tracks will have a big impact on how much precipitation we see and whether it will be rain or snow. However, as mentioned, a weak La Niña (which is what this year is shaping up to be) has been tied to higher-than-normal snow in Iowa.

So this winter could be snowier and colder than normal. But what does that mean? Average highs through the winter are in the low to mid-30s, and lows are typically in the teens to low 20s. Of course, every winter also has its ups and downs, but the averages are pointing in the direction of being colder than normal. This may not necessarily mean being colder all winter long, but shorter periods of intense cold could bring down winter temperature averages.

No matter what the winter brings, the WHO 13 weather team will have you covered! Stay tuned for the very latest as we approach the winter months.