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Green Bay weather by month: averages, rainfall & climate trends

Green Bay swings through a wide annual range, with 53.6°F between the monthly means of its warmest and coldest months. Rainfall leans toward the stretch from April to September. Green Bay weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.

Today vs average

−1.4°Fhigh near average

52° / 46°Today
53° / 40°Average
see today in detail →

How it's changed

+3.6°Faverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–49128frost days a year now (2016–2025) · 148 in the 1940sfrost days a year · 148 in the 1940s19days above 86°F a year now (2016–2025) · 12 in the 1940sdays above 86°F · 12 in the 1940s+3.6°F vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 1.6 incheshigh 25°low 11°February, rain 1.4 incheshigh 29°low 14°March, rain 2.4 incheshigh 40°low 24°April, rain 3.2 incheshigh 55°low 36°May, rain 3.4 incheshigh 67°low 47°June, rain 3.6 incheshigh 77°low 58°July, rain 3.5 incheshigh 81°low 63°August, rain 3.5 incheshigh 79°low 61°September, rain 3.0 incheshigh 71°low 53°October, rain 2.6 incheshigh 59°low 43°November, rain 2.4 incheshigh 43°low 31°December, rain 1.9 incheshigh 30°low 18°wettest month June, 3.6 inches · 32.4 inches a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Overcast

Right now

51.1°

47°feels like
73%humidity
43°dew point
6 mphfrom N
UV index0.0
sunrise07:22sunset17:49day length10h 28m
TodayOvercast52°46°
TueOvercast56°44°
WedClear70°54°
ThuOvercast66°49°
FriOvercast60°44°
SatOvercast59°43°
SunOvercast57°52°

On this date: October 26

Today (forecast)
52° / 46°
Average for October 26
53° / 40°

High near average · −1.4°F

  • Highest since 1940: 75.6° · 1989
  • Lowest since 1940: 20.6° · 1962
  • One year ago: 57° / 31°

Every October 26 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 26 on record (n = 87). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for Green Bay is sampled from the ECMWF ERA5 reanalysis at 44.52°N, 88.02°W, with daily records since 1940.

Coordinates
44.52°N, 88.02°W
Time zone
America/Chicago
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

26 of the last 31 days were warmer than the historical average for that date. Average difference: +5.2°F.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

The year peaks in July, at around 81.2°F by mid-afternoon, with nights around 62.6°F. Roughly 20 days a year now top 86°F. In January, the coolest month, afternoons reach about 25.2°F and nights dip to 11.2°F. Around 130 days a year dip below freezing.

In total, Green Bay averages about 32.4 inches of precipitation a year; June is usually the wettest month (3.6 inches) and February the driest (1.4 inches).

The record here starts in 1940, and since then the annual mean in Green Bay has climbed 3.6°F from the first ten years to the last ten. The last decade has also run wetter, about 9% above the long-term precipitation average.

Climate graph (climograph)

July is the warmest month, January the coolest: a yearly swing of 54°F. Wettest month: June (~3.6 in). Whole year averages ~32.4 inches of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Rainy days by month

About 89 rainy days a year: most in June (~9), fewest in February (~5).

Bars = average number of days with ≥ 0.08 in per month. Hover for the monthly rainfall total.

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

Green Bay month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Highest and Lowest are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainRainy daysDaylightHighestLowest
January25.2°11.2°1.6 in69.0 h53.4° (2025)−29.4° (1951)
February29.0°13.7°1.4 in510.2 h69.8° (2024)−27.9° (1996)
March39.9°23.8°2.4 in711.6 h83.1° (2012)−20.9° (1962)
April54.7°36.1°3.2 in913.3 h88.6° (1980)5.0° (2003)
May67.1°47.4°3.4 in914.6 h94.0° (1988)19.0° (1940)
June76.8°57.7°3.6 in915.3 h100.0° (1987)34.4° (1945)
July81.2°62.6°3.5 in915.0 h103.1° (1995)44.0° (1965)
August78.9°61.0°3.5 in813.9 h100.2° (1988)39.8° (1965)
September70.9°53.1°3.0 in812.3 h97.7° (1953)27.6° (1964)
October58.8°42.7°2.6 in710.7 h87.7° (2025)16.8° (1988)
November43.4°30.6°2.4 in79.3 h74.6° (2020)−4.8° (1950)
December30.2°17.8°1.9 in68.7 h63.3° (2021)−26.2° (1983)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +3.6°F.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.45°F per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Dec–Feb is warming fastest: +0.72°F per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 86°F per year: 12.3 early in the record → 19.4 recently. Frost days: 148 → 128.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

Hottest day since 1940 in 1995, coldest in 1951: 103.1°F / −29.4°F.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~32.4 in/year on average. Last decade: +9% vs that average. Long-term trend: +0.46 in per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about Green Bay

Which is the warmest month in Green Bay?
On long-term average, the warmest month in Green Bay is July (mean daily temperature of about 71.3°F) and the coolest is January (about 17.6°F).
How does today's temperature in Green Bay compare to the historical average?
On October 26, 2026, Green Bay is forecast to reach a high of 51.8°F and a low of 45.9°F. The long-term average for this date (the full record since 1940) is a high of 53.2°F and a low of 39.6°F, so today's high is 1.4°F cooler than that average.
How much has Green Bay warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Green Bay is about 3.6°F warmer.
How much does it rain in Green Bay?
Green Bay receives about 32.4 inches of precipitation per year on long-term average, with June typically the wettest month.
What is the average temperature in Green Bay?
Over the full record (since 1940), the annual mean temperature in Green Bay is about 45.8°F. The warmest month is July and the coolest is January.
What are the average temperatures in Green Bay by month?
Average daily highs and lows for each month in Green Bay (°F, full record since 1940): January 25°/11°, February 29°/14°, March 40°/24°, April 55°/36°, May 67°/47°, June 77°/58°, July 81°/63°, August 79°/61°, September 71°/53°, October 59°/43°, November 43°/31°, December 30°/18°.
What is the weather like in Green Bay in summer?
June to August is summer in Green Bay, and it is warm. Daytime highs sit at 77–81°F and nights at 58–63°F; July is the warmest month. Rain is steady at around 3.5 inches a month, spread over roughly 9 days.
What is the weather like in Green Bay in winter?
In winter, December through February, Green Bay is cold, with afternoons close to freezing. Afternoons run 25–30°F and nights 11–18°F; January is the coldest month. Snow is steady at around 1.6 inches of precipitation a month, spread over roughly 5 days. It is the driest season of the year.
What is the weather like in Green Bay in spring?
Spring in Green Bay (March to May) is cool. March is still 40°F in the afternoon and 24°F at night, May already 67°F and 47°F. Rain is steady at around 3.0 inches a month, spread over roughly 8 days.
What is the weather like in Green Bay in autumn?
September to November is autumn in Green Bay, and it is cool. September still brings 71°F afternoons and 53°F nights, November only 43°F and 31°F. Rain falls on about 7 days a month, adding up to around 2.6 inches.
How many days a year does it rain in Green Bay?
On long-term average, Green Bay has about 89 days a year with at least 0.08 inches of rain or snow. The annual total is roughly 32.4 inches.

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