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Gillett has four hard seasons and very little in between. Gillett weather runs from July afternoons that average about 81 degrees to January mornings that average about 7, with roughly 53 inches of snow in a typical winter. What that means for a visit depends on why you are coming. The river and the fair want summer, the ATV trails want late spring through October, and the snowmobile trails want a cold, snowy January.
This page is about the long-run pattern, month by month, and what each season is good for. For tomorrow's forecast, use the National Weather Service or a forecast site, and use this to decide which weekend to come.
Gillett weather by month
July is the warmest month in Gillett and January is the coldest, and the averages below are long-term climate figures rather than a forecast.
- January: high 25°F, low 7°F, 1.4 inches of precipitation.
- February: high 29°F, low 9°F, 1.2 inches.
- March: high 40°F, low 19°F, 1.8 inches.
- April: high 54°F, low 32°F, 3.3 inches.
- May: high 67°F, low 44°F, 3.7 inches.
- June: high 77°F, low 54°F, 4.7 inches, the wettest month.
- July: high 81°F, low 58°F, 3.8 inches.
- August: high 79°F, low 56°F, 3.7 inches.
- September: high 72°F, low 48°F, 3.6 inches.
- October: high 58°F, low 36°F, 3.0 inches.
- November: high 43°F, low 26°F, 1.9 inches.
- December: high 30°F, low 14°F, 1.7 inches.
Across a year that adds up to about 34 inches of precipitation, with most of it falling as rain between April and October. Gillett sits in USDA plant hardiness zone 5a, which is gardener shorthand for cold winters.
Summer: river, trails and fair week
June through August is the warm season, with average highs in the upper 70s to about 81 degrees in July and cool nights in the 50s. June is the wettest month, and summer rain tends to arrive as afternoon and evening thunderstorms rather than all-day drizzle. Plan outdoor afternoons with a weather app open, and get off the water or the trail when the sky darkens.
August is fair month: the county fair in August fills Zippel Park with 4-H barns and grandstand pulls, and August highs average around 79 degrees. Barns get hot by mid-afternoon, and evenings at the grandstand cool off quickly, so bring a layer.
Fall: frost, color and the end of ATV season
The first frost usually arrives in early October, and the last spring frost is usually in mid-May, which leaves Gillett a growing season of about five months. September is still mild, with highs averaging about 72 degrees, and October drops to the upper 50s.
Fall is the season many riders wait for, because the leaf color along the Oconto County trails peaks in early fall and the ATV trails out of Zippel Park stay open to ATVs through October in Oconto County. Late September through mid-October is the window. Dress for 40-degree mornings even when the afternoon reaches the 60s.
Fall rain is steady rather than stormy, with about 3 inches in October, and wet weeks can close trails while they dry. Check the county trail report before you drive up with a trailer.
Winter: snow and the snowmobile season
Gillett gets about 53 inches of snow in an average winter, and December is usually the snowiest month, at about 12.7 inches. Measurable snow usually starts in November and the last of it falls in April, while May through October are snow-free.
January is the coldest month, with average highs around 25 degrees and lows around 7, and nights below zero are part of a normal winter. Wind chill on a moving snowmobile makes it feel much colder, so dress for the ride rather than the thermometer.
Once the snow base builds, the Nicolet State Trail becomes a main snowmobile corridor, connected to more than 400 miles of sled trail across Oconto County. ATVs come off the Oconto County trails for the winter. Across from the trailhead, Spirits advertises snowmobile trail access, which is a welcome thing on a ten-degree afternoon.
Snow totals swing a lot from year to year. A thin or warm winter can keep the sled trails closed for weeks, so check conditions before you book.
Spring: thaw and mud season
March is still a winter month in Gillett, with average highs around 40 degrees, and April brings the thaw, with highs in the mid-50s and the first real rain. This is mud season. Trails close while the ground thaws and dries, and the river runs high and cold.
Oconto County opens its ATV trails in late April or early May once conditions allow, and the opening is posted by the county rather than fixed in advance. Further north on the Nicolet State Trail, Florence County closes its section to ATVs during the spring thaw, roughly mid-March to mid-May.
May warms quickly to highs in the upper 60s, and the last frost usually lands between May 11 and May 20. Late May is a quiet, pleasant time to visit, before the summer trail crowds and after the mud.
What to pack by season
Summer: light clothes, a rain shell for the afternoon storms, sunscreen and bug spray, plus a sweater for evenings that drop into the 50s. On the river, water shoes and a dry bag for phones and keys matter more than anything else you bring.
Fall: layers. October mornings average in the 30s and afternoons in the upper 50s, so a warm jacket you can strip off by noon is the right call. On the trails, add goggles and gloves. The dust and the cold both come at you faster on a moving machine.
Winter: real cold-weather gear, not city winter clothes. With January lows around 7 degrees, a snowmobile suit, insulated boots, a balaclava and a helmet with a clear visor are the baseline. Pack hand warmers and a spare pair of gloves. Wet gloves at ten degrees end a ride early.
Spring: waterproof boots. March and April bring thaw and mud, and highs can swing from the 30s to the 50s in the same week. If you are coming to ride, check that the trails have opened before you load up.
Storms, heat and other weather to watch
June is the wettest month in Gillett, and summer storms tend to build in the afternoon heat. On the river or the trail, lightning is the real risk. Get off the water and away from open ground as soon as you hear thunder.
Heavy rain also raises the Oconto River and can turn trails to mud, and the county can close trails after a wet spell. A dry forecast for your day does not mean the trail is dry if it poured the night before.
In winter, the risk is cold and wind more than snow. A clear, still January night is beautiful and bitterly cold, and wind on an open stretch of trail makes it feel far colder than the thermometer says.
The best time to visit Gillett
The answer turns on what you want to do. For the river and summer riding, come June through August; for the fair, come in mid to late August; for fall color on an ATV, come from late September to mid-October; for snowmobiling, come in January or February when the snow base is reliable.
If you want the town at its liveliest, fair week is it. If you want the trails quiet and the air cool, the second week of October is hard to beat. Once you have picked your season, start with the things to do in Gillett, from the trailhead and the river to the museum and the diner on Main Street.
Checking the forecast
The nearest reporting weather station that forecast sites use for Gillett is at Shawano Municipal Airport, about 17 miles to the west-southwest. Before a riding or river day, check the National Weather Service forecast for Gillett the night before and again in the morning, and keep an eye on radar in summer. Storms build fast on hot afternoons.
Frequently asked questions
Published September 7, 2026
