May 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

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. May proves to be the harbinger of summer, with increased daylight and longer sunshine hours. The higher temperatures and blooming natural vegetation provide ample opportunities to explore the outdoors. Hence, May paints Green Bay with the hues of late spring leading into early summer.

Temperature

The onset of May brings a temperature shift, with the average high-temperature moving from a cool 50.2°F (10.1°C) in April to a comfortable 63.3°F (17.4°C). May brings with it a nighttime average temperature of 45.3°F (7.4°C).

Humidity

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

Rainfall

The month with the most rainfall is May, when the rain falls for 15.9 days and typically aggregates up to 3.31" (84mm) of precipitation.

Snowfall

January through May, October through December are months with snowfall. May is the last month it regularly snows. During 0.2 snowfall days, in May, Green Bay aggregates 0.24" (6mm) of snow. Throughout the year, there are 63.7 snowfall days, and 23.27" (591mm) of snow is accumulated.

Ocean temperature

In Green Bay, the average seawater temperature in May is 41.4°F (5.2°C).
Note: Being in 41.4°F (5.2°C) waters at 55.4°F (13°C) is discomforting, but anything below 50°F (10°C) can jeopardize breathing and induce cold shock, factoring in physical endurance.

Daylight

In Green Bay, the average length of the day in May is 14h and 49min.
On the first day of May, sunrise is at 5:41 am and sunset at 7:57 pm. On the last day of the month, sunrise is at 5:10 am and sunset at 8:29 pm CDT.

Sunshine

In Green Bay, the average sunshine in May is 8.8h.

UV index

The average daily maximum UV index in May is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for the average person.
Note: The maximum daily UV index, 4 in May, converts into the following recommendations:
Heed the precautions - Suggestions to avoid sunburn are made. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Notice! The UV radiation of the Sun can be intensified nearly twofold due to the reflective quality of snow.
Updated: Aug 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Green Bay in May?

In Green Bay, 63.3°F (17.4°C) is the average high-temperature and 45.3°F (7.4°C) is the average low-temperature during May.

What is the least humid month?

April and May, with an average relative humidity of 76%, are the least humid months.

What is the average humidity in May?

The average relative humidity in May is 76%.

What is the wettest month?

The month with the most rainfall is May, when the rain falls for 15.9 days and typically aggregates up to 3.31" (84mm) of precipitation.

How many days does it rain in May?

In Green Bay, in May, during 15.9 rainfall days, 3.31" (84mm) of precipitation is typically accumulated.

What is the last month it snows in Green Bay?

May is the last month it regularly snows. During 0.2 snowfall days, in May, Green Bay aggregates 0.24" (6mm) of snow.

How cold is the water in May?

In Green Bay, in May, the average water temperature is 41.4°F (5.2°C). Swimming in 41.4°F (5.2°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

What is the average length of the day in May?

The average day length in May is 14h and 49min.

When are sunrise and sunset in May?

On the first day of May, sunrise is at 5:41 am and sunset at 7:57 pm. On the last day of the month, sunrise is at 5:10 am and sunset at 8:29 pm CDT.

How long on average sun shines in May?

The average sunshine duration in May is 8.8h.

How high is the UV index in May?

The average daily maximum UV index in May in Green Bay is 4. A UV Index of 3 to 5 symbolizes a moderate health threat from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Green Bay, WI

Average temperature in May - Green Bay, WI
  • Average high temperature in May: 63.3°F

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).

  • Average low temperature in May: 45.3°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).

Average pressure in May
Green Bay, WI

Average pressure in May - Green Bay, WI
  • Average pressure in May: 29.96"Hg

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

Average wind speed in May
Green Bay, WI

Average wind speed in May - Green Bay, WI
  • Average wind speed in May: 8.7mph

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).

Average humidity in May
Green Bay, WI

Average humidity in May - Green Bay, WI
  • Average humidity in May: 76%

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

Average rainfall in May
Green Bay, WI

Average rainfall in May - Green Bay, WI
  • Average rainfall in May: 3.31"

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

Average rainfall days in May
Green Bay, WI

Average rainfall days in May - Green Bay, WI
  • Average rainfall days in May: 15.9 days

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).

Average snowfall in May
Green Bay, WI

Average snowfall in May - Green Bay, WI
  • Average snowfall in May: 0.24"

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

Average snowfall days in May
Green Bay, WI

Average snowfall days in May - Green Bay, WI
  • Average snowfall days in May: 0.2 days

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).

Average sea temperature in May
Green Bay, WI

Average sea temperature in May - Green Bay, WI
  • Average sea temperature in May: 41.4°F

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).

Average daylight in May /
Average sunshine in May
Green Bay, WI

Average daylight in May / Average sunshine in May - Green Bay, WI
  • Average daylight in May: 14h and 5min

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).

  • Average sunshine in May: 8h and 5min

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).

Average sunshine days in May
Green Bay, WI

Average sunshine days in May - Green Bay, WI
  • Average sunshine days in May: 13.3 days

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).

Average UV index in May
Green Bay, WI

Average UV index in May - Green Bay, WI
  • Average UV index in May: 4

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).

Average cloud cover in May
Green Bay, WI

Average cloud cover in May - Green Bay, WI
  • Average cloud cover in May: 42

The month with the most cloud cover is January (Cloud cover 65).
The months with the least cloud cover are July and August (Cloud cover 33).

Average visibility in May
Green Bay, WI

Average visibility in May - Green Bay, WI
  • Average visibility in May: 6mi

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).

Green Bay, Wisconsin, USA

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