Green Bay, Wisconsin climate: Normal weather by month, frost dates and records
Green Bay's normal year runs from 11°F January nights to 81°F July afternoons, with 31.6 inches of precipitation and 56 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.6°C, January lows of −12°C, July highs of 27°C, 803 mm of precipitation a year.
- NOAA stationGreen Bay A S International Airport
- Station IDUSW00014898
- Location44.50°N 88.11°W
- Elevation682 ft (208 m)
- From the center6 miles
- Population106,311
On October 23, the normal high in Green Bay is 55°F and the normal low 37°F, and the chance of measurable rain or snow is 32%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Green Bay.
- Jan 26° 11°
- Feb 29° 13°
- Mar 40° 24°
- Apr 54° 35°
- May 67° 46°
- Jun 77° 56°
- Jul 81° 60°
- Aug 79° 58°
- Sep 72° 50°
- Oct 58° 40°
- Nov 44° 29°
- Dec 31° 18°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Green Bay each month?
July is the warmest month, with normal highs of 81°F; January the coldest, with normal lows of 11°F. The most precipitation falls in June (4.10 in), the least in February (1.20 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 26°F | 11°F | 18.3°F | 1.39 | 14.3 | 11 | <1 | 30 | 9 h 10 min |
| February | 29°F | 13°F | 21.1°F | 1.20 | 12.0 | 9 | <1 | 27 | 10 h 30 min |
| March | 40°F | 24°F | 32.1°F | 1.96 | 8.1 | 10 | <1 | 25 | 11 h 50 min |
| April | 54°F | 35°F | 44.3°F | 3.00 | 4.7 | 12 | <1 | 12 | 13 h 30 min |
| May | 67°F | 46°F | 56.5°F | 3.35 | 0.0 | 12 | <1 | 1 | 14 h 50 min |
| June | 77°F | 56°F | 66.4°F | 4.10 | 0.0 | 11 | 2 | <1 | 15 h 30 min |
| July | 81°F | 60°F | 70.5°F | 3.62 | 0.0 | 11 | 3 | <1 | 15 h 10 min |
| August | 79°F | 58°F | 68.6°F | 3.39 | 0.0 | 10 | 1 | <1 | 14 h 10 min |
| September | 72°F | 50°F | 61.0°F | 3.20 | 0.0 | 10 | <1 | 1 | 12 h 40 min |
| October | 58°F | 40°F | 48.7°F | 2.67 | 0.3 | 10 | <1 | 8 | 11 h |
| November | 44°F | 29°F | 36.2°F | 1.98 | 3.1 | 10 | <1 | 21 | 9 h 40 min |
| December | 31°F | 18°F | 24.5°F | 1.75 | 13.1 | 11 | <1 | 28 | 8 h 50 min |
| Year (annual) | 55°F | 37°F | 45.7°F | 31.61 | 55.6 | 126 | 6 | 152 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −4°C | −12°C | −7.6°C | 35 mm | 36 cm |
| February | −2°C | −10°C | −6.1°C | 30 mm | 30 cm |
| March | 5°C | −5°C | 0.1°C | 50 mm | 21 cm |
| April | 12°C | 2°C | 6.8°C | 76 mm | 12 cm |
| May | 19°C | 8°C | 13.6°C | 85 mm | 0 cm |
| June | 25°C | 13°C | 19.1°C | 104 mm | 0 cm |
| July | 27°C | 16°C | 21.4°C | 92 mm | 0 cm |
| August | 26°C | 15°C | 20.3°C | 86 mm | 0 cm |
| September | 22°C | 10°C | 16.1°C | 81 mm | 0 cm |
| October | 14°C | 4°C | 9.3°C | 68 mm | 1 cm |
| November | 6°C | −2°C | 2.3°C | 50 mm | 8 cm |
| December | 0°C | −8°C | −4.2°C | 44 mm | 33 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014898; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Green Bay?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (10).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014898.
When is the last frost in Green Bay?
In Green Bay, the last spring frost (32°F) comes after April 30 in half of years and after May 16 in one year in ten; the first autumn frost comes before October 9 in half of years and before September 24 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 301 year in 10 after May 16; 9 in 10 after April 16
- First autumn frost, half of years before
- October 91 year in 10 before September 24; 9 in 10 before October 26
NOAA puts the median frost-free season at 161 days, and the season without a hard freeze (28°F) at 187 days.
A hard freeze (28°F) comes after April 17 in half of springs and before October 24 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Green Bay in zone 5b across its 5 ZIP code areas (5b in 54311, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Green Bay's NOAA station is in zone 5a: the coldest night of a typical year reaches −16°F (30 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Wisconsin · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00014898; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Green Bay ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Green Bay's 5 ZIP code areas are all in zone 5b. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Green Bay?
In a normal year in Green Bay, 6 days a year reach 90°F, 152 nights fall to 32°F or colder and 126 days bring measurable precipitation.
- Days at 90°F or more
- 6a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 152a normal year
- Days that stay below freezing
- 66high of 32°F or less
- Days with 0.01 inch of precipitation
- 126a normal year
- Days with 1 inch of snow or more
- 17a normal year
The highest temperature in Green Bay's official record (kept by the National Weather Service since 1886) is 104°F, on July 13, 1936; the lowest is −36°F, on January 21, 1888.
The wettest calendar year on that record is 2019, with 48.63 in; the snowiest season is 1887–88, with 143.7 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00014898; records: ACIS (NOAA Regional Climate Centers), NWS threaded record GRBthr. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Green Bay, and how clear are its skies?
The summer (June-August) dew point averages 60°F. The muggiest month is July, with an average dew point of 61°F; the driest air comes in January (12°F). April is the windiest month (9.9 mph on average), and August has the most clear or nearly clear hours (68%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 12°F | 73% | 65% | 9.1 mph | 47% | 43% |
| February | 17°F | 72% | 61% | 9.2 mph | 49% | 40% |
| March | 29°F | 68% | 55% | 9.9 mph | 49% | 37% |
| April | 38°F | 63% | 47% | 9.9 mph | 56% | 30% |
| May | 51°F | 69% | 52% | 8.2 mph | 60% | 24% |
| June | 60°F | 71% | 55% | 7.5 mph | 66% | 17% |
| July | 61°F | 74% | 55% | 6.5 mph | 68% | 15% |
| August | 59°F | 77% | 57% | 6.6 mph | 68% | 16% |
| September | 46°F | 74% | 54% | 8.1 mph | 60% | 25% |
| October | 34°F | 73% | 58% | 9.0 mph | 49% | 40% |
| November | 23°F | 76% | 66% | 9.2 mph | 44% | 46% |
| December | 15°F | 76% | 69% | 9.3 mph | 44% | 47% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014898. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Green Bay?
Over a year 72% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Green Bay, 3.8 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (58%). Among the 459 U.S. places of 50,000 or more, that ranks tied 385th (with 30 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 65% | 1.6 |
| February | 72% | 2.7 |
| March | 72% | 3.8 |
| April | 68% | 4.6 |
| May | 71% | 5.6 |
| June | 74% | 6.1 |
| July | 80% | 6.3 |
| August | 77% | 5.3 |
| September | 76% | 4.1 |
| October | 68% | 2.6 |
| November | 65% | 1.7 |
| December | 58% | 1.2 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Green Bay need?
A normal year in Green Bay brings 7,505 heating degree days, 40% more than the median U.S. place (5,373), and 508 cooling degree days, 44% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,428 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,448 | 0 |
| February | 1,229 | 0 |
| March | 1,019 | 0 |
| April | 622 | 1 |
| May | 288 | 26 |
| June | 65 | 107 |
| July | 14 | 186 |
| August | 27 | 137 |
| September | 169 | 47 |
| October | 507 | 4 |
| November | 864 | 0 |
| December | 1,254 | 0 |
| Year (annual) | 7,505 | 508 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014898. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Green Bay been warmer than normal lately?
2025 averaged 46.2°F, 0.5°F above the 1991-2020 normal of 45.7°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 47.8°F | +2.1°F | 29.56 | 43.0 |
| 2022 | 46.4°F | +0.7°F | 33.56 | 38.0 |
| 2023 | 48.3°F | +2.6°F | 27.65 | 67.7 |
| 2024 | 50.1°F | +4.4°F | 34.69 | 50.6 |
| 2025 | 46.2°F | +0.5°F | 26.33 | 56.8 |
Over 133 complete years from 1887 to 2025, the station's annual mean temperature rose at a fitted 2.8°F per century (+0.16°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00014898; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Green Bay's climate compare?
Green Bay is warmer than 94 of the other 164 places with their own NOAA record in Wisconsin, and wetter than 20. Across the 7,247 U.S. stations with normals, its annual mean of 45.7°F is warmer than 22%.
In the Köppen classification computed from these normals, Green Bay is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Green Bay share this climate record?
5 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- De Pere, WI25,453 people · 5 mi S
- Howard, WI21,961 people · 5 mi N
- Bellevue, WI16,749 people · 8 mi E
- Allouez, WI13,923 people · 5 mi SE
- Suamico, WI13,109 people · 10 mi NE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Green Bay's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Green Bay. This page uses Green Bay A S International Airport; the other differs by site and elevation:
| Station | From the center | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Green Bay Botanical USC00473271 | 6 mi W | 694 ft | 44.7°F | 9°F | 80°F | 32.4 | – | May 7 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Green Bay's climate
What is the coldest month in Green Bay?
January, with a normal high of 26°F and a normal low of 11°F. The warmest is July (81°F by day, 60°F at night).
Does it snow in Green Bay?
Yes: 56 inches in a normal year, falling on 41 days with 0.1 inch or more, the most in January (14.3 inches).
What is the rainiest month in Green Bay?
June, with 4.10 in of precipitation in a normal year; the driest is February with 1.20 in.
What plant hardiness zone is Green Bay in?
The USDA's 2023 map puts Green Bay in zone 5b across its 5 ZIP code areas (5b in 54311, the largest). By the same method at Green Bay's NOAA station, the coldest night of a typical year reaches −16°F (30 years, 1991-2020): zone 5a.
How late can frost come in Green Bay?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 16. Waiting until May 16 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Green Bay in OctoberThis month day by day, its records and recent years
- Wisconsin climateThe statewide normals and every place in the state
- Ashwaubenon, WI0 miles from this station, 45.1°F a year
- Denmark, WI18 miles from this station, 44.7°F a year
- Appleton, WI22 miles from this station, 45.6°F a year
- Brillion, WI24 miles from this station, 45.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made