May weather forecast
Southwest, PA

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Weather in May

The last month of the spring, May, is a pleasant month in Southwest, Pennsylvania, with an average temperature ranging between max 70.7°F (21.5°C) and min 50°F (10°C).

Temperature

An increase in the average high-temperature marks May, moving from April's refreshing 59.5°F (15.3°C) to an agreeable 70.7°F (21.5°C). The average low-temperature during May nights is a cool 50°F (10°C).

Humidity

In Southwest, the average relative humidity in May is 79%.

Rainfall

May is the month with the most rainfall. Rain falls for 22 days and accumulates 3.66" (93mm) of precipitation.

Snowfall

Months with snowfall are January through May, October through December. May is the last month it regularly snows. During 0.4 snowfall days, in May, Southwest aggregates 0.16" (4mm) of snow. Throughout the year, there are 63.2 snowfall days, and 29.02" (737mm) of snow is accumulated.

Daylight

In Southwest, the average length of the day in May is 14h and 25min.
On the first day of the month, sunrise is at 6:16 am and sunset at 8:13 pm. On the last day of May, sunrise is at 5:50 am and sunset at 8:41 pm EDT.

Sunshine

In Southwest, the average sunshine in May is 8.8h.

UV index

In Southwest, the average daily maximum UV index in May is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: A maximum high daily UV index of 5 during May translates into the following directions:
Be mindful. Those with pale skin might receive burns in fewer than 30 minutes. To guard against the harmful effects of the Sun, minimize exposure during midday. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
Updated: Jul 21, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average May temperature?

An average high-temperature, in May, in Southwest, is 70.7°F (21.5°C) and the average low-temperature is 50°F (10°C).

What is the average humidity in May?

In Southwest, Pennsylvania, the average relative humidity in May is 79%.

What is the wettest month?

May is the month with the most rainfall. Rain falls for 22 days and accumulates 3.66" (93mm) of precipitation.

How many days does it rain in May?

In Southwest, in May, it is raining for 22 days, with typically 3.66" (93mm) of accumulated precipitation.

What is the last month it snows?

May is the last month it regularly snows in Southwest. During 0.4 snowfall days, in May, Southwest aggregates 0.16" (4mm) of snow.

What is the average length of the day in May?

In May, the average day length is 14h and 25min.

When are sunrise and sunset in May?

On the first day of May, sunrise is at 6:16 am and sunset at 8:13 pm. On the last day of the month, sunrise is at 5:50 am and sunset at 8:41 pm EDT.

How many hours of sunshine does Southwest have in May?

In May, the average sunshine duration is 8.8h.

What is the UV index intensity in May?

The average daily maximum UV index in May is 5. 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
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Southwest, PA

Average temperature in May - Southwest, PA
  • Average high temperature in May: 70.7°F

The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (33.3°F).

  • Average low temperature in May: 50°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 (20.3°F).

Average pressure in May
Southwest, PA

Average pressure in May - Southwest, PA
  • Average pressure in May: 30"Hg

The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).

Average wind speed in May
Southwest, PA

Average wind speed in May - Southwest, PA
  • Average wind speed in May: 6.4mph

The windiest month (with the highest average wind speed) is January (8.5mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).

Average humidity in May
Southwest, PA

Average humidity in May - Southwest, PA
  • Average humidity in May: 79%

The months with the highest relative humidity are January and February (85%).
The months with the lowest relative humidity are April, July and August (77%).

Average rainfall in May
Southwest, PA

Average rainfall in May - Southwest, PA
  • Average rainfall in May: 3.66"

The wettest month (with the highest rainfall) is May (3.66").
The driest month (with the least rainfall) is November (2.01").

Average rainfall days in May
Southwest, PA

Average rainfall days in May - Southwest, PA
  • Average rainfall days in May: 22 days

The month with the highest number of rainy days is May (22 days).
The month with the least rainy days is January (9.8 days).

Average snowfall in May
Southwest, PA

Average snowfall in May - Southwest, PA
  • Average snowfall in May: 0.16"

The month with the highest snowfall is January (7.09").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in May
Southwest, PA

Average snowfall days in May - Southwest, PA
  • Average snowfall days in May: 0.4 days

The month with the highest number of snowfall days is January (17.3 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in May /
Average sunshine in May
Southwest, PA

Average daylight in May / Average sunshine in May - Southwest, PA
  • Average daylight in May: 14h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in May: 8h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).

Average sunshine days in May
Southwest, PA

Average sunshine days in May - Southwest, PA
  • Average sunshine days in May: 8 days

The month with the most sunshine days is November (13.5 days).
The month with the least sunshine days is January (6.5 days).

Average UV index in May
Southwest, PA

Average UV index in May - Southwest, PA
  • Average UV index in May: 5

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in May
Southwest, PA

Average cloud cover in May - Southwest, PA
  • Average cloud cover in May: 45

The month with the most cloud cover is January (Cloud cover 69).
The month with the least cloud cover is August (Cloud cover 35).

Average visibility in May
Southwest, PA

Average visibility in May - Southwest, PA
  • Average visibility in May: 5mi

The month with the highest visibility is April (6mi).
The months with the lowest visibility are January and February (4mi).

Southwest, Pennsylvania, USA

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