Contents
- Weather in January
- Frequently asked questions
- Average temperature in January
- Average pressure in January
- Average wind speed in January
- Average humidity in January
- Average rainfall in January
- Average rainfall days in January
- Average snowfall in January
- Average snowfall days in January
- Average sea temperature in January
- Average daylight in January
- Average sunshine in January
- Average sunshine days in January
- Average UV index in January
- Average cloud cover in January
- Average visibility in January
Weather in January
Temperature
Port Jefferson experiences its lowest temperatures in January, with an average peak of 37.6°F (3.1°C) and a low of 29.1°F (-1.6°C).Humidity
In January, the average relative humidity in Port Jefferson is 72%.Rainfall
The month with the least rainfall is January, when the rain falls for 6.8 days and typically collects 2.05" (52mm) of precipitation.Snowfall
January through March, October through December are months with snowfall. In Port Jefferson, during January, snow falls for 3.5 days and regularly aggregates up to 0.94" (24mm) of snow. In Port Jefferson, during the entire year, snow falls for 12.6 days and aggregates up to 5.59" (142mm) of snow.Ocean temperature
In Port Jefferson, the average seawater temperature in January is 42.3°F (5.7°C).Note: Swimming at temperatures less than 50°F (10°C) in 42.3°F (5.7°C) is feasible with the right swimsuit; if not, expect cold shock and breathlessness. A quick swim at 55.4°F (13°C) without adequate warmth can be discomforting.
Daylight
In Port Jefferson, the average length of the day in January is 9h and 38min.On the first day of January in Port Jefferson, sunrise is at 7:16 am and sunset at 4:34 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 5:07 pm EST.
Sunshine
In Port Jefferson, the average sunshine in January is 5.1h.UV index
The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: During January, 2 as the daily maximum UV index converts into the following advice:
It is important to always shield children, babies, and individuals with sensitive skin from prolonged exposure to the sun. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.
Frequently asked questions
What month is the coldest in Port Jefferson?
How cold does it get in Port Jefferson in January?
What is the average humidity in January in Port Jefferson?
What is the driest month in Port Jefferson?
How many days does it rain in January in Port Jefferson?
How many days does it snow in January in Port Jefferson?
What is the water temperature in January in Port Jefferson?
What is the average length of the day in January in Port Jefferson?
What time are sunrise and sunset in January in Port Jefferson?
How many hours of sunshine does Port Jefferson have in January?
What are the months with the lowest UV index in Port Jefferson?
What is the UV index intensity in January in Port Jefferson?
Average temperature in January
Port Jefferson, NY
- Average high temperature in January: 37.6°F
The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is January (37.6°F).
- Average low temperature in January: 29.1°F
The months with the highest average low temperature are July and August (71.1°F).
The coldest month (with the lowest average low temperature) is January (29.1°F).
Average pressure in January
Port Jefferson, NY
- Average pressure in January: 30.04"Hg
The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in January
Port Jefferson, NY
- Average wind speed in January: 12.9mph
The windiest month (with the highest average wind speed) is January (12.9mph).
The calmest month (with the lowest average wind speed) is July (8.3mph).
Average humidity in January
Port Jefferson, NY
- Average humidity in January: 72%
The months with the highest relative humidity are May and June (77%).
The month with the lowest relative humidity is November (71%).
Average rainfall in January
Port Jefferson, NY
- Average rainfall in January: 2.05"
The wettest month (with the highest rainfall) is December (3.58").
The driest month (with the least rainfall) is January (2.05").
Average rainfall days in January
Port Jefferson, NY
- Average rainfall days in January: 6.8 days
The month with the highest number of rainy days is July (16.5 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in January
Port Jefferson, NY
- Average snowfall in January: 0.94"
The month with the highest snowfall is March (2.13").
The months with the least snowfall are April, May, June, July, August and September (0").
Average snowfall days in January
Port Jefferson, NY
- Average snowfall days in January: 3.5 days
The month with the highest number of snowfall days is February (4.4 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in January
Port Jefferson, NY
- Average sea temperature in January: 42.3°F
The best month for swimming (with the highest average sea temperature) is August (74°F).
The coldest month (with the lowest average sea temperature) is February (39.7°F).
Average daylight in January /
Average sunshine in January
Port Jefferson, NY
- Average daylight in January: 9h and 4min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in January: 5h and 1min
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 42min).
Average sunshine days in January
Port Jefferson, NY
- Average sunshine days in January: 19.8 days
The month with the most sunshine days is November (20.5 days).
The month with the least sunshine days is July (13 days).
Average UV index in January
Port Jefferson, NY
- Average UV index in January: 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 January
Port Jefferson, NY
- Average cloud cover in January: 45
The month with the most cloud cover is December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in January
Port Jefferson, NY
- Average visibility in January: 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).
Port Jefferson, New York, USA
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