Climate and monthly weather forecast
Green Bay, WI

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The sun setting over Green Bay in Wisconsin
The sun setting over Green Bay in Wisconsin

The climate of Green Bay

Green Bay, located in the state of Wisconsin USA, falls under the Dfb category of the Köppen climate classification. This category is characterized as a humid continental climate with moderate populations of both flora and fauna. The key features of this climate include no dry season and warm summers.

Weather patterns across the year display significant variations due to the continental influence. The monthly temperature highs in Green Bay range from 22.6°F (-5.2°C) in January to 78.1°F (25.6°C) in July whereas the lows fluctuate between 12.4°F (-10.9°C) in January and 60.4°F (15.8°C) in July. This broadly reflects the changing conditions from the cold winter months to the warmer summer period.

Relative humidity, an indicator of the air's moisture content, is fairly high throughout the year, with the least humid month being April at 76%, escalating up to a high of 88% during January. Rainfall occurs consistently year-round amounting from 1.18" (30mm) in January to a peak of 3.31" (84mm) in May. However, snowfall is concentrated in the colder months, from a high of 5.79" (147mm) in February, reducing to negligible quantities between May and September before starting to accumulate again in October.

The amount of daylight experienced in Green Bay fluctuates noticeably with the progression of the seasons. January sees an average of 9.3 hours of daylight, increasing to a peak of 15.5 hours in June. The associated sunshine hours, indicating bright and clear skies, range from a low of 3.4 hours in January to a remarkable high of 10.1 hours in July.

The best time to visit Green Bay

The optimal time to visit Green Bay would be during the summer months from June to August. The temperatures are pleasantly warm, averaging between 50.2°F (10.1°C) to 77°F (25°C). With 15.5 hours of daylight in June and high average sunshine hours (9.3 hours in June), it offers ample opportunity for sightseeing and outdoor activities.

The worst time to visit Green Bay

The harshest months in Green Bay are typically in winter, specifically from December to February. Temperatures during this period can drop as low as 12.4°F (-10.9°C) in January, coupled with significant snowfall. These chilly conditions can prove too harsh for those unaccustomed to intense winter environments.

Spring weather in Green Bay

Examples of comfortable climates can be seen in Green Bay during spring from March to May; it sees a steady climb in temperatures, ranging from 38.5°F (3.6°C) to 63.3°F (17.4°C), and a rise in daylight hours. Rainfall also starts to intensify during these months, reaching a peak at 3.31" (84mm) in May, indicating the start of the city's wet season.

Summer weather in Green Bay

Summer in Green Bay, ushered in June and stretching until August, is generally warmer with temperatures peaking at around 78.1°F (25.6°C) in July. Relative humidity remains steady, providing some cooling relief. The hours of sunshine and daylight are at their highest, allowing for ample opportunities for outdoor activities.

Autumn weather in Green Bay

Autumn in Green Bay, from September to November, brings about a gradual drop in temperatures from 69.6°F (20.9°C) in September to 41.7°F (5.4°C) in November. This period also witnesses a decrease in rainfall to around 1.57" (40mm) by November, making it relatively drier compared to other seasons.

Winter weather in Green Bay

Winter in Green Bay, from December to February, is starkly cold with average high temperatures hovering between 22.6°F (-5.2°C) to 28.8°F (-1.8°C). These months also see an escalation in snowfall, peaking at 5.79" (147mm) in February. Reduced daylight hours and low sunshine hours make this season appear gloomy. Visitors during these months should prepare for freezing temperatures and heavily overcast skies.

Weather in January

Green Bay, Wisconsin, witnesess some of its coldest days in January, as temperatures generally range from a low of 12.4°F (-10.9°C) to a high of 22.6°F (-5.2°C). With overcast skies being a common sight, the rays of sunshine are limited to an average of just 3.5 hours per day. Weather in January »

Weather in February

As Green Bay transitions through February, slight moderation in temperatures can be observed, yet winters still grip the city. The days grow longer, and the city witnesses daylight for 10.5 hours on average. Though temperatures start to rise marginally, February records an average snowfall of 5.79" (147mm). Weather in February »

Weather in March

The onset of spring in March brings a respite from harsh winter temperatures in Green Bay, with significant rise in temperatures alongside an increase in rainfall. Average highs and lows for the month range from 25.5°F (-3.6°C) to 38.5°F (3.6°C) making the weather slightly more endurable. Weather in March »

Weather in April

April comes with a pronounced change in weather, with the mercury rising above 50°F (10°C) during the daytime. April also introduces more rainfall to Green Bay, with an average monthly rainfall of 2.56" (65mm). Along with this, there’s a noticeable lengthening in daylight hours and an increase in the number of sunshine hours. Weather in April »

Weather in May

May brings about a considerable rise in temperature, transforming Green Bay into sun-filled spaces with temperatures maxing between 63.3°F (17.4°C). With the onset of a warmer climate, the ice starts to melt and the chances of snowfall dwindle significantly to almost none. Weather in May »

Weather in June

June ushers in the season of summer in Green Bay, with longest daylight hours of the year and increased sunshine duration. The warm temperature, ranging to about 72.1°F (22.3°C) as the average high, marks the beginning of a short but vibrant summer season. Weather in June »

Weather in July

July is when Green Bay experiences the height of summer, with temperatures soaring to an average high of 78.1°F (25.6°C) making it the hottest month of the year. Despite the heat, the city maintains relatively high humidity levels, making the heat slightly more oppressive. Weather in July »

Weather in August

As August rolls in, there is a slight dip in temperature from July’s peak but the city continues to bask under summer's radiance. With highs only slightly dropping to 77°F (25°C), August continues to feel like the heart of summer. Weather in August »

Weather in September

September signals the onset of fall in Green Bay, with a gradual tapering of temperatures. The sky remains clear for most of the month, and the city enjoys 8.4 hours of average daily sunshine. It also marks a transition from warm to mildly cool weather, hinting at the approaching winter with temperatures dropping to an average 52.3°F (11.3°C) towards the end of the month. Weather in September »

Weather in October

October witnesses a noticeable drop in temperature, and the vibrant hues of fall are in full display in Green Bay. With decreasing daylight hours, the longer and cooler nights make their presence felt. The weather during October is notorious for its unpredictability with temperatures oscillating between highs of 55.8°F (13.2°C) and lows around 41.9°F (5.5°C). Weather in October »

Weather in November

Contrasting the relatively mild October, November in Green Bay is a prelude to the harsh winter, and the temperatures plunge significantly. The cooling temperatures give way to more frequent snowfall, with an average of 1.5" (38mm) falling in November. Weather in November »

Weather in December

December is dominated by cold temperatures and snowfall, prepping Green Bay for the deep winter ahead. With an average snowfall of 4.76" (121mm), December ranks second in snowfall accumulation, next only to January. The daylight hours drop to a mere 8.9 hours, the shortest in the year, with sun shining for only around 3.6 hours a day on average. Weather in December »
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Frequently asked questions

What is the coldest time of year in Green Bay?

The coldest period in Green Bay is January, when temperatures fluctuate between an average high of 22.6°F (-5.2°C) and a low of 12.4°F (-10.9°C).

What is the most humid month in Green Bay?

The most humid month in Green Bay, Wisconsin, is January, with an average relative humidity of 88%.

What is the driest month in Green Bay?

January is the month with the least rainfall. Rain falls for 4.6 days and accumulates 1.18" (30mm) of precipitation.

How much does it rain in Green Bay?

In Green Bay, during the entire year, the rain falls for 130.8 days and collects up to 24.8" (630mm) of precipitation.

When does it snow in Green Bay?

Months with snowfall in Green Bay, Wisconsin, are January through May, October through December.

How much does it snow in Green Bay?

In Green Bay, during the entire year, snow falls for 63.7 days and aggregates up to 23.27" (591mm) of snow.

What are the months with the lowest UV index in Green Bay?

The months with the lowest UV index in Green Bay are January, February, November and December, with an average maximum UV index of 1.

When does it snow the most in Green Bay?

The month with the most snowfall in Green Bay, Wisconsin, is February, when snow falls for 13.9 days and typically aggregates up to 5.79" (147mm) of snow.

What month is the ocean coldest in Green Bay?

February is the month with the coldest seawater in Green Bay, Wisconsin, with an average ocean temperature of 36.1°F (2.3°C).

What is the month with the least sunshine in Green Bay?

With an average of 3.4h of sunshine, February has the least sunshine of the year.

When is Daylight Saving Time (DST) in Green Bay?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Green Bay, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

What is the least humid month in Green Bay?

The months with the lowest humidity in Green Bay are April and May, with an average relative humidity of 76%.

What is the wettest month in Green Bay?

May is the month with the most rainfall in Green Bay. Rain falls for 15.9 days and accumulates 3.31" (84mm) of precipitation.

When it does not snow in Green Bay?

June through September are months without snowfall in Green Bay.

When are the longest days in Green Bay?

June has the longest days of the year, with an average of 15h and 30min of daylight.

What are the months with the highest UV index in Green Bay?

The months with the highest UV index in Green Bay, Wisconsin, are June through August, with an average maximum UV index of 5.

What time of the year is the hottest in Green Bay?

July tends to be the warmest month in Green Bay, with temperatures averaging a daily high of 78.1°F (25.6°C) and a low of 60.4°F (15.8°C).

What month has the most sunshine in Green Bay?

With an average of 10.1h of sunshine, July has the most sunshine of the year in Green Bay, Wisconsin.

When is the ocean warmest in Green Bay?

The month with the warmest seawater in Green Bay, Wisconsin, is August, with an average ocean temperature of 67.6°F (19.8°C).

What is the month with the shortest days in Green Bay?

With an average of 8h and 54min of daylight, December has the shortest days of the year in Green Bay, Wisconsin.

Average temperature
Green Bay, WI

Average temperature - Green Bay, WI

The warmest month (with the highest average high temperature) is July (78.1°F).
The month with the lowest average high temperature is January (22.6°F).

The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is January (12.4°F).

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Average pressure
Green Bay, WI

Average pressure - Green Bay, WI

The month with the highest atmospheric pressure is March (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed
Green Bay, WI

Average wind speed - Green Bay, WI

The windiest months (with the highest average wind speed) are January and February (10.1mph).
The calmest months (with the lowest average wind speed) are July and August (7.2mph).

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Average humidity
Green Bay, WI

Average humidity - Green Bay, WI

The month with the highest relative humidity is January (88%).
The months with the lowest relative humidity are April and May (76%).

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Average rainfall
Green Bay, WI

Average rainfall - Green Bay, WI

The wettest month (with the highest rainfall) is May (3.31").
The driest month (with the least rainfall) is January (1.18").

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Average rainfall days
Green Bay, WI

Average rainfall days - Green Bay, WI

The month with the highest number of rainy days is May (15.9 days).
The month with the least rainy days is February (3.7 days).

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Average snowfall
Green Bay, WI

Average snowfall - Green Bay, WI

The month with the highest snowfall is February (5.79").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days
Green Bay, WI

Average snowfall days - Green Bay, WI

The month with the highest number of snowfall days is January (15.9 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average sea temperature
Green Bay, WI

Average sea temperature - Green Bay, WI

The best month for swimming (with the highest average sea temperature) is August (67.6°F).
The coldest month (with the lowest average sea temperature) is February (36.1°F).

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Average daylight / Average sunshine
Green Bay, WI

Average daylight / Average sunshine - Green Bay, WI

The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).

The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is February (Average sunshine: 3h and 24min).

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Average sunshine days
Green Bay, WI

Average sunshine days - Green Bay, WI

The months with the most sunshine days are September and November (17 days).
The month with the least sunshine days is April (11.6 days).

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Average UV index
Green Bay, WI

Average UV index - Green Bay, WI

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).

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Average visibility
Green Bay, WI

Average visibility - Green Bay, WI

The months with the highest visibility are March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and February (5mi).

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Green Bay, Wisconsin, USA

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