Green Bay climate
Green Bay (Wisconsin, United States) has a warm-summer humid continental climate (Köppen Dfb). The average temperature over the year is 8 °C46 °F, and about 878 mm35 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Green Bay climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | −425 | −1211 | −818 | 341.3 | 30 |
| Feb | −228 | −1112 | −720 | 351.4 | 28 |
| Mar | 440 | −523 | 031 | 542.1 | 27 |
| Apr | 1152 | 133 | 643 | 853.4 | 14 |
| May | 1864 | 745 | 1254 | 1024.0 | 1 |
| Jun | 2374 | 1356 | 1865 | 1134.5 | 0 |
| Jul | 2780 | 1762 | 2271 | 893.5 | 0 |
| Aug | 2679 | 1661 | 2170 | 893.5 | 0 |
| Sep | 2272 | 1254 | 1763 | 853.4 | 0 |
| Oct | 1457 | 541 | 949 | 873.4 | 4 |
| Nov | 643 | −130 | 337 | 532.1 | 19 |
| Dec | −131 | −818 | −424 | 512.0 | 29 |
| Year | 2780 | −1211 | 846 | 87835 | 152 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total. Frost days are for the whole grid cell.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 90% | 67% | 1.6 | 9:11 |
| Feb | 88% | 63% | 2.7 | 10:22 |
| Mar | 81% | 62% | 3.8 | 11:47 |
| Apr | 77% | 64% | 4.6 | 13:25 |
| May | 77% | 64% | 5.6 | 14:47 |
| Jun | 78% | 58% | 6.1 | 15:32 |
| Jul | 75% | 48% | 6.3 | 15:13 |
| Aug | 74% | 51% | 5.3 | 14:02 |
| Sep | 76% | 51% | 4.1 | 12:27 |
| Oct | 79% | 62% | 2.7 | 10:53 |
| Nov | 83% | 67% | 1.7 | 9:31 |
| Dec | 89% | 72% | 1.2 | 8:50 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Green Bay is like
The warmest month is July, with an average high of 27 °C80 °F and a low of 17 °C62 °F. The coldest is January, when highs average −4 °C25 °F and lows −12 °C11 °F. Seasons are strongly marked: the warmest month is on average 29.6 °C53.4 °F warmer than the coldest.
Annual precipitation is moderate at about 878 mm35 in. The wettest three-month stretch is May–July, which brings 35% of the annual total. The wettest month is June (113 mm4.5 in), the driest is January (34 mm1.3 in).
Relative humidity ranges from 74% in August to 90% in January. The clearest skies (lowest average cloud amount, 48%) are typical of July. Average wind speed near the ground ranges from 10 km/h (6 mph) in July to 16 km/h (10 mph) in February. Daylight lasts from about 8.8 hours in December to 15.5 hours in June.
A lasting snow cover is typical in December–March, when the average snow depth in the reanalysis exceeds 10 cm (deepest in January, about 17 cm).
Best time to visit Green Bay
Based on these averages, the most comfortable months for sightseeing and outdoor activities are July–September: average highs of 22 °C72 °F to 27 °C80 °F with 85 mm3.4 in to 89 mm3.5 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of −4 °C25 °F.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Green Bay
- Winter (December–February) — highs −425 to −1 °C31 °F, lows −1211 to −8 °C18 °F, about 40 mm1.6 in of precipitation a month. Pack a winter coat, hat, gloves and warm, non-slip boots and shoes with good grip, as frost is common.
- Spring (March–May) — highs 440 to 18 °C64 °F, lows −523 to 7 °C45 °F, about 80 mm3.2 in of precipitation a month. Pack a warm coat, layers and closed shoes and an extra layer for the cooler mornings and evenings.
- Summer (June–August) — highs 2374 to 27 °C80 °F, lows 1356 to 17 °C62 °F, about 97 mm3.8 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses, an extra layer for the cooler mornings and evenings and an umbrella or light rain jacket.
- Autumn (September–November) — highs 643 to 22 °C72 °F, lows −130 to 12 °C54 °F, about 75 mm3.0 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket.
How Green Bay compares
Compared with Milwaukee, about 165 km to the south, Green Bay is on average 1.2 °C2.1 °F cooler and receives 7% less precipitation (878 mm35 in vs 945 mm37 in). The difference is largest in March (1.7 °C3 °F cooler).
Of the 222 places in the United States covered by World Climates, Green Bay is the 218th warmest by annual mean temperature and the 134th wettest by annual precipitation. See all of them on the United States climate page.
Places in other countries with the most similar temperature and rainfall pattern: Guelph (Canada, Dfb), Kitchener (Canada, Dfb) and Obihiro (Japan, Dfb).
Nearby places
- Milwaukee 165 km · 9 °C48 °F · 945 mm37 in
- Madison 195 km · 8 °C47 °F · 970 mm38 in
- Grand Rapids 256 km · 9 °C48 °F · 967 mm38 in
- Rockford 265 km · 9 °C48 °F · 967 mm38 in
- Elgin 277 km · 10 °C49 °F · 983 mm39 in
- Chicago 298 km · 10 °C50 °F · 982 mm39 in
- Aurora 308 km · 10 °C49 °F · 983 mm39 in
- Joliet 333 km · 10 °C51 °F · 985 mm39 in
Frequently asked questions
What is the warmest month in Green Bay?
July is the warmest month in Green Bay, with an average high of 27 °C (80 °F) and an average low of 17 °C (62 °F).
What is the coldest month in Green Bay?
January is the coldest month, with an average high of -4 °C (25 °F) and an average low of -12 °C (11 °F).
When does it rain the most in Green Bay?
June is the wettest month with about 113 mm (4.5 in) of precipitation; January is the driest with about 34 mm (1.3 in).
What is the best time to visit Green Bay?
Judging by long-term averages, the most comfortable months are July–September.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.