May weather forecastGrantham, PA

May

Weather in May

The last month of the spring, May, is a pleasant month in Grantham, Pennsylvania, with an average temperature fluctuating between 52.3°F (11.3°C) and 70.3°F (21.3°C).

Temperature

Grantham's transition into May brings a rise in the average high-temperature, moving from a mild 60.4°F (15.8°C) in April to a pleasant 70.3°F (21.3°C). An average low-temperature of 52.3°F (11.3°C) marks the nights in Grantham throughout May.

Humidity

The months with the highest humidity are February and May, with an average relative humidity of 80%.

Rainfall

The months with the most rainfall are May and July, with an average 2.05" (52mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In May, the average length of the day is 14h and 25min.
On the first day of the month, sunrise is at 6:06 am and sunset at 8:03 pm. On the last day of May, sunrise is at 5:40 am and sunset at 8:30 pm EDT.

Sunshine

In May, the average sunshine is 8.5h.

UV index

The months with the highest UV index are May through July, with an average maximum UV index of 6. A UV Index of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: The daily maximum UV index of 6 in May interprets into the following advice:
Undertake precautions and comply with sun safety standards. Protection from skin and eye injury is vital. Avoid direct Sun exposure and stay in the shade between 10 a.m. and 4 p.m., a time when UV radiation is most intense, noting that not all shade structures offer full protection. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Pay attention! The reflection of snow can enhance the Sun's UV radiation almost double.

Updated: Jul 17, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

In May, in Grantham, the average high-temperature is 70.3°F (21.3°C), and the average low-temperature is 52.3°F (11.3°C).

The months with the highest humidity are February and May, with an average relative humidity of 80%.

In Grantham, the average relative humidity in May is 80%.

The wettest months are May and July, with an average 2.05" (52mm) of rainfall.

In Grantham, in May, it is raining for 15.6 days, with typically 2.05" (52mm) of accumulated precipitation.

In Grantham, snow does not fall in May through September.

In May, it doesn't snow. April is the latest month when it typically snows.

The average day length in May in Grantham is 14h and 25min.

In May, on the first day of the month, sunrise is at 6:06 am and sunset at 8:03 pm. On the last day of the month, sunrise is at 5:40 am and sunset at 8:30 pm EDT.

In Grantham, the average sunshine duration in May is 8.5h.

May through July, with an average maximum UV index of 6, are months with the highest UV index.

In May, the average daily maximum UV index is 6. A UV Index estimate of 6 to 7 represents a high health risk from unprotected exposure to UV radiation.

Today

Tomorrow

Long-term

Year J F M A May J J A S O N D

Apr

May

Jun

Average high temperature

60.4°F

70.3°F

78.3°F

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

9.2mph

7.1mph

6.6mph

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

Average daylight

Average sunshine

Average sunshine days

13.3

12.2

12.6

Average UV index

Average cloud cover

Average visibility

Average temperature in May
Grantham, PA

Average high temperature in May: 70.3°F

The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (35.2°F).

Average low temperature in May: 52.3°F

The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).

Average pressure in May
Grantham, PA

Average pressure in May: 30.01"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
Grantham, PA

Average wind speed in May: 6.5mph

The windiest months (with the highest average wind speed) are February, March and April (8.4mph).
The calmest months (with the lowest average wind speed) are July and August (5mph).

Average humidity in May
Grantham, PA

Average humidity in May: 80%

The months with the highest relative humidity are February and May (80%).
The month with the lowest relative humidity is April (75%).

Average rainfall in May
Grantham, PA

Average rainfall in May: 2.05"

The wettest months (with the highest rainfall) are May and July (2.05").
The driest month (with the least rainfall) is January (1.14").

Average rainfall days in May
Grantham, PA

Average rainfall days in May: 15.6 days

The month with the highest number of rainy days is May (15.6 days).
The month with the least rainy days is January (6.3 days).

Average snowfall in May
Grantham, PA

Average snowfall in May: 0"

The month with the highest snowfall is January (2.52").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in May
Grantham, PA

Average snowfall days in May: 0.1 days

The month with the highest number of snowfall days is January (7.2 days).
The months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in May: 14h and 24min

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 30min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).

Average sunshine days in May
Grantham, PA

Average sunshine days in May: 12.2 days

The month with the most sunshine days is November (20 days).
The month with the least sunshine days is May (12.2 days).

Average UV index in May
Grantham, PA

Average UV index in May: 6

The months with the highest UV index are May, June and 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
Grantham, PA

Average cloud cover in May: 46

The months with the most cloud cover are February and December (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 30).

Average visibility in May
Grantham, PA

Average visibility in May: 5mi

The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).