Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
In December, the average high-temperature decreases from a frosty 49.3°F (9.6°C) in November to a wintry 39.2°F (4°C). Watertown registers a consistent average low-temperature of 28.8°F (-1.8°C) during December.Humidity
The average relative humidity in December is 76%.Rainfall
In Watertown, in December, it is raining for 6.1 days, with typically 0.55" (14mm) of accumulated precipitation. In Watertown, Massachusetts, during the entire year, the rain falls for 85.9 days and collects up to 5.87" (149mm) of precipitation.Snowfall
January through May, November and December are months with snowfall. The month with the most snowfall is December, when snow falls for 2.6 days and typically aggregates up to 0.91" (23mm) of snow.Daylight
The month with the shortest days is December, with an average of 9h and 6min of daylight.On the first day of the month, sunrise is at 6:54 am and sunset at 4:13 pm. On the last day of December, sunrise is at 7:13 am and sunset at 4:22 pm EST.
Sunshine
The average sunshine in December is 4.9h.UV index
January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health hazard from unsafe exposure to UV radiation for the ordinary person.Note: In December, the maximum UV index of 2 translates into these guidelines:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. During bright days, sunglasses that offer UVA and UVB defense are recommended. Mind you! Snow reflection can increase the intensity of the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it cold in Watertown during December?
What is the average humidity in December?
How many days does it rain in December?
What is the snowiest month?
How many days does it snow in December?
What is the month with the shortest days in Watertown?
What is the average length of the day in December?
When are sunrise and sunset in December?
How long on average sun shines in December in Watertown?
What is the month with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Watertown, MA
- Average high temperature in December: 39.2°F
The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is January (33.6°F).
- Average low temperature in December: 28.8°F
The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (21.7°F).
Average pressure in December
Watertown, MA
- Average pressure in December: 30.03"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 December
Watertown, MA
- Average wind speed in December: 8.6mph
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 December
Watertown, MA
- Average humidity in December: 76%
The month with the highest relative humidity is February (78%).
The month with the lowest relative humidity is April (70%).
Average rainfall in December
Watertown, MA
- Average rainfall in December: 0.55"
The wettest month (with the highest rainfall) is November (0.67").
The driest month (with the least rainfall) is September (0.24").
Average rainfall days in December
Watertown, MA
- Average rainfall days in December: 6.1 days
The month with the highest number of rainy days is July (10.2 days).
The month with the least rainy days is February (4.1 days).
Average snowfall in December
Watertown, MA
- Average snowfall in December: 0.91"
The month with the highest snowfall is December (0.91").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in December
Watertown, MA
- Average snowfall days in December: 2.6 days
The month with the highest number of snowfall days is January (4.9 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Watertown, MA
- Average daylight in December: 9h and 1min
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 December: 4h and 5min
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 December
Watertown, MA
- Average sunshine days in December: 22.2 days
The months with the most sunshine days are January and November (22.5 days).
The month with the least sunshine days is June (17.5 days).
Average UV index in December
Watertown, MA
- Average UV index in December: 2
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 December
Watertown, MA
- Average cloud cover in December: 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 December
Watertown, MA
- Average visibility in December: 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).
Watertown, Massachusetts, USA
Weather forecast for your location
2. Allow the app to use your location