Wisconsin winter warmth: why 40s in January aren't always good

Highs climbing into the mid and even upper 40s during the second week of January is not typical for Wisconsin, even in milder winters. 

Midweek thaw, what that means for Wisconsin

What we know:

Average high temperatures for early January are usually in the upper 20s to low 30s for the region, making this midweek warm-up a solid 10 to 15 degrees above average for our area and much of the state. 

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This kind of thaw is being driven by a strong push of warm air from the south, temporarily breaking winter’s grip before more seasonal weather returns later in the week.

What this means on the ground

Why you should care:

Snowpack

Warmer temperatures accelerate snow-melt, especially where snow is shallow or compacted. Rain further accelerates the melting process. 

Expect slushy conditions on sidewalks, trails, and secondary roads, along with ponding in low-lying areas. While this can be helpful for reducing immediate snow removal issues, rapid melting can refreeze overnight, creating slick spots for the early morning commute.

Ice fishing, ice safety

This thaw is a red flag for ice anglers. Ice does not melt evenly, and warmer days followed by colder nights can weaken ice from below. Ice along shorelines, near pressure cracks, and in areas near inlets can become especially dangerous during thaws. Even if ice looks solid, conditions can change quickly.

Winter recreation

Snowmobiling, cross-country skiing, and outdoor rinks may see deteriorating conditions midweek. Trails soften, snow cover thins, and groomed surfaces break down faster. For many outdoor enthusiasts, this becomes a short pause in winter activities rather than the end of the season.

Mild temperatures for Wisconsin

6-10 Day Temperature Trend Above Average

What this means overall

Big picture view:

January thaws are not unheard of, but extended stretches of 40-degree weather do stand out and tend to have outsized impacts on snow cover and ice stability. 

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With colder air and a higher likelihood of snow returning by the weekend, this warm-up looks temporary, but it serves as a reminder that midwinter weather in Wisconsin can change fast. Stay tuned for updated conditions and always take safety precautions on the ice and on area trails and roads.

The Source: Information in this post was produced by the FOX 6 Weather Experts with help from the National Weather Service.

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