Contents
- Weather in May
- Frequently asked questions
- Average temperature in May
- Average pressure in May
- Average wind speed in May
- Average humidity in May
- Average rainfall in May
- Average rainfall days in May
- Average snowfall in May
- Average snowfall days in May
- Average daylight in May
- Average sunshine in May
- Average sunshine days in May
- Average UV index in May
- Average cloud cover in May
- Average visibility in May
Weather in May
Temperature
The transition from April to May brings a temperature rise, with average high-temperatures increasing from a refreshing 55.9°F (13.3°C) to an enjoyable 66.9°F (19.4°C). Throughout May, Waltham anticipates an average low-temperature of 49.6°F (9.8°C).Humidity
The average relative humidity in May is 73%.Rainfall
In May, in Waltham, the rain falls for 10.6 days. Throughout May, 0.75" (19mm) of precipitation is accumulated. In Waltham, during the entire year, the rain falls for 106.3 days and collects up to 8.5" (216mm) of precipitation.Snowfall
January through May, November and December are months with snowfall. May is the last month it regularly snows. During 0.1 snowfall days, in May, Waltham aggregates 0.04" (1mm) of snow. Throughout the year, there are 19.6 snowfall days, and 4.02" (102mm) of snow is accumulated.Daylight
In Waltham, the average length of the day in May is 14h and 37min.On the first day of May, sunrise is at 5:38 am and sunset at 7:45 pm. On the last day of the month, sunrise is at 5:10 am and sunset at 8:14 pm EDT.
Sunshine
The average sunshine in May is 8.4h.UV index
The average daily maximum UV index in May is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the ordinary person.Note: In May, an average UV index of 5 transforms into the following instructions:
Take precautions - Protection against sunburn is recommended. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Be on the lookout! Nearly twofold UV radiation from the Sun can be reflected by snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are May temperatures?
What is the average humidity in May?
How many days does it rain in May?
What is the last month it snows?
How many hours of daylight does Waltham have in May?
When are sunrise and sunset in May?
How many hours of sunshine does Waltham have in May?
What is the UV index reading in May?
Average temperature in May
Waltham, MA
- Average high temperature in May: 66.9°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: 49.6°F
The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).
Average pressure in May
Waltham, MA
- Average pressure in May: 30.01"Hg
The month with the highest atmospheric pressure is November (30.07"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in May
Waltham, MA
- Average wind speed in May: 7mph
The windiest month (with the highest average wind speed) is January (9.1mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).
Average humidity in May
Waltham, MA
- Average humidity in May: 73%
The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (70%).
Average rainfall in May
Waltham, MA
- Average rainfall in May: 0.75"
The wettest months (with the highest rainfall) are April and November (0.87").
The driest month (with the least rainfall) is September (0.35").
Average rainfall days in May
Waltham, MA
- Average rainfall days in May: 10.6 days
The month with the highest number of rainy days is July (12.4 days).
The month with the least rainy days is January (5.3 days).
Average snowfall in May
Waltham, MA
- Average snowfall in May: 0.04"
The month with the highest snowfall is December (1.14").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in May
Waltham, MA
- Average snowfall days in May: 0.1 days
The month with the highest number of snowfall days is February (5.4 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in May /
Average sunshine in May
Waltham, MA
- Average daylight in May: 14h and 4min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in May: 8h and 2min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in May
Waltham, MA
- Average sunshine days in May: 17 days
The month with the most sunshine days is January (22.2 days).
The month with the least sunshine days is June (15.8 days).
Average UV index in May
Waltham, MA
- Average UV index in May: 5
The months with the highest UV index are June, July and August (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
Waltham, MA
- Average cloud cover in May: 46
The month with the most cloud cover is March (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in May
Waltham, MA
- Average visibility in May: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Waltham, Massachusetts, USA
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