About the Weather in Green BayBy Kathy Adams; Updated August 11, 2017
Experience four distinctive seasons in Wisconsin's oldest city
Green Bay, Wis. offers a little something for everyone when it comes to weather and seasons. Those who enjoy winter snow will appreciate the views during December and January in Green Bay. Likewise, the weather is warm enough to swim or partake in outdoor sports during the summer months.
Winter wonderland, right here
Green Bay can feel extremely cold in the winter if you're not used to a northern climate. The average high temperature for December through March is approximately 27 degrees, with January's average high only 24 degrees. While the highs seem reasonable for winter, the average seasonal lows are quite chilly. January has the coldest average low temperature at only 9 degrees F, with February following close behind at 12 degrees F. January and December tie for the most monthly snowfall at 13 inches.
Winter lingers into Spring
Springtime brings with it nicer weather and early blooming flowers such as daffodils, but in Green Bay, it may also bring more snow. March still averages 8 inches of snow each year, with an average high of 39 degrees F and an average low of 22 degrees F. If planning a visit during March, be sure to bring winter outerwear, hats and gloves and potentially even boots if you plan to spend time outdoors. Check the upcoming forecast to get a general idea what to expect during your visit. The same holds true in April. Snow can fall even as flowers start to sprout. April averages 3 inches of snow in Green Bay each year, with average daily highs of 54 and lows of 34.
Hot fun in the summertime
Summers are seasonably warm in Green Bay, but generally not so hot you'll think you're in the tropics. Although the average high in the hottest month of July is only 81 degrees F, temperatures can still soar into the 90s in the summer. Green Bay averages about eight above-90-degree days every year, but in the past three decades, two years have experienced more than 20 days reaching above 90. Summer months can also be quite humid in Green Bay. The average humidity year-round is 72 percent, which may help the air feel a bit better in cold weather. In August, the average humidity is 75 percent, so it may feel a bit swampy much of the time. Air conditioning can provide some much-needed relief if you're visiting during days that are in the mid- to upper-80s or hotter. Green Bay gets 3 to 4 inches of rainfall during summer months, so you may need an umbrella from time to time. By comparison, the average springtime rainfall amounts average an inch less.
Autumn splendor, in full color
Autumn is a gorgeous time of year in Green Bay as the leaves start to change color. With many varieties of trees, you'll spot some leaves changing color by late September, with spectacular colors on display in the first half of October. September weather can be gorgeous for outdoor activities such as hiking and biking, with average daily highs at 70 degrees F. By October, the average daily high drops to 57 and the average low to 38 degrees, so plan on wearing layers or even bringing gloves and a hat, especially if visiting late in the month. November gets even cooler, with average highs of 42 and lows of 27, so plan on experiencing some frost or even a little snowfall. November averages 4 inches of snow in Green Bay, so check the forecasts ahead of time when planning an autumn road trip.