Climate and monthly weather forecast
Port Jefferson, NY

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Weather in January

January, the same as December, is an icy winter month in Port Jefferson, New York, with an average temperature ranging between max 37.6°F (3.1°C) and min 29.1°F (-1.6°C). 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). Weather in January »

Weather in February

February, the last month of the winter in Port Jefferson, is another cold month, with an average temperature varying between 38.8°F (3.8°C) and 30.4°F (-0.9°C). February brings a marginal elevation to a still wintry 38.8°F (3.8°C) from January's 37.6°F (3.1°C) in Port Jefferson's average high-temperatures. Weather in February »

Weather in March

The first month of the spring, March, is a frosty month in Port Jefferson, New York, with an average temperature varying between 43.9°F (6.6°C) and 36°F (2.2°C). Port Jefferson sees the arrival of March with an average high-temperature of a frosty 43.9°F (6.6°C), indicating a subtle variation from February. Weather in March »

Weather in April

April in Port Jefferson, New York, is a fresh spring month, with temperature in the range of an average high of 52.9°F (11.6°C) and an average low of 44.6°F (7°C). The start of April signals an increase in the average high-temperature, moving from a frosty 43.9°F (6.6°C) in March to a fresh 52.9°F (11.6°C). Weather in April »

Weather in May

The last month of the spring, May, is a refreshing month in Port Jefferson, New York, with an average temperature ranging between max 62.6°F (17°C) and min 53.6°F (12°C). Port Jefferson's May weather brings a rise in high-temperatures, moving from a fresh 52.9°F (11.6°C) in April to a refreshing 62.6°F (17°C). Weather in May »

Weather in June

The first month of the summer, June, is an agreeable month in Port Jefferson, New York, with an average temperature ranging between min 63.1°F (17.3°C) and max 71.2°F (21.8°C). The shift from May to June sees a slight increase in the average high-temperature, transitioning from a comfortable 62.6°F (17°C) to a pleasant 71.2°F (21.8°C). Weather in June »

Weather in July

July is a warm summer month in Port Jefferson, New York, with an average temperature ranging between max 79.2°F (26.2°C) and min 71.1°F (21.7°C). Port Jefferson notes the warmest temperatures in July, with a high average of 79.2°F (26.2°C) and a low of 71.1°F (21.7°C). Weather in July »

Weather in August

The last month of the summer, August, is also a moderately hot month in Port Jefferson, New York, with an average temperature ranging between min 71.1°F (21.7°C) and max 78.4°F (25.8°C). Port Jefferson registers an average high-temperature of a still warm 78.4°F (25.8°C) at the commencement of August, closely related to the preceding month. Weather in August »

Weather in September

The first month of the autumn, September, is also an agreeable month in Port Jefferson, New York, with temperature in the range of an average low of 64.8°F (18.2°C) and an average high of 72.3°F (22.4°C). As August makes way for September, Port Jefferson's average high-temperature eases from a warm 78.4°F (25.8°C) to a pleasant 72.3°F (22.4°C). Weather in September »

Weather in October

October, like September, in Port Jefferson, New York, is another enjoyable autumn month, with an average temperature ranging between min 55.4°F (13°C) and max 62.6°F (17°C). The start of October signals a decrease in the average high-temperature, transitioning from a pleasant 72.3°F (22.4°C) in September to an enjoyable 62.6°F (17°C). Weather in October »

Weather in November

November, the last month of the autumn in Port Jefferson, is another cool month, with an average temperature fluctuating between 51.8°F (11°C) and 44.1°F (6.7°C). November is characterized by a reduction in the average high-temperature, from a refreshing 62.6°F (17°C) in October to a cool 51.8°F (11°C). Weather in November »

Weather in December

The first month of the winter, December, is still a chilly month in Port Jefferson, New York, with an average temperature fluctuating between 36.5°F (2.5°C) and 43.7°F (6.5°C). December brings a minor shift in the average high-temperature, adjusting from a cool 51.8°F (11°C) in November to a frosty 43.7°F (6.5°C). Weather in December »
Updated: Feb 13, 2024 | Published by: Weather U.S. | Resources

Frequently asked questions

What month is the coldest in Port Jefferson?

January, with average temperatures reaching a high of 37.6°F (3.1°C) and a low of 29.1°F (-1.6°C), is the coldest month in Port Jefferson.

What is the driest month in Port Jefferson?

The month with the least rainfall is January, when the rain falls for 6.8 days and typically collects 2.05" (52mm) of precipitation.

How many days does it rain in Port Jefferson?

In Port Jefferson, New York, during the entire year, the rain falls for 146.8 days and collects up to 33.78" (858mm) of precipitation.

When does it snow in Port Jefferson?

Months with snowfall in Port Jefferson, New York, are January through March, October through December.

How many days does it snow in Port Jefferson?

In Port Jefferson, during the entire year, snow falls for 12.6 days and aggregates up to 5.59" (142mm) of snow.

What are the months with the lowest UV index in Port Jefferson?

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Port Jefferson.

What month is the ocean coldest in Port Jefferson?

The month with the coldest seawater in Port Jefferson is February, with an average ocean temperature of 39.7°F (4.3°C).

What is the month with the least sunshine in Port Jefferson?

The month with the least sunshine is February, with an average of 4.7h of sunshine.

When does it snow the most in Port Jefferson?

The month with the most snowfall in Port Jefferson is March, when snow falls for 2.3 days and typically aggregates up to 2.13" (54mm) of snow.

When is Daylight Saving Time (DST) in Port Jefferson?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from EDT to EST.

When it does not snow in Port Jefferson?

In Port Jefferson, New York, snow does not fall in April through September.

What are the most humid months in Port Jefferson?

The months with the highest humidity in Port Jefferson are May and June, with an average relative humidity of 77%.

When are the longest days in Port Jefferson?

With an average of 15h and 6min of daylight, June has the longest days of the year in Port Jefferson, New York.

When is the highest UV index in Port Jefferson?

June through August, with an average maximum UV index of 6, are months with the highest UV index.

What are the warmest months in Port Jefferson?

July is the month when Port Jefferson's temperatures reach their peak, with averages of 79.2°F (26.2°C) and lows of 71.1°F (21.7°C).

What month has the most sunshine in Port Jefferson?

July has the most sunshine of the year in Port Jefferson, with an average of 10.6h of sunshine.

When is the ocean warmest in Port Jefferson?

The month with the warmest seawater is August, with an average ocean temperature of 73.9°F (23.3°C).

What is the least humid month in Port Jefferson?

The least humid month is November, with an average relative humidity of 71%.

What is the wettest month in Port Jefferson?

The month with the most rainfall is December, when the rain falls for 11.4 days and typically aggregates up to 3.58" (91mm) of precipitation.

What is the month with the shortest days in Port Jefferson?

The month with the shortest days in Port Jefferson, New York, is December, with an average of 9h and 18min of daylight.

Average temperature
Port Jefferson, NY

Average temperature - Port Jefferson, NY

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).

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).

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Average pressure
Port Jefferson, NY

Average pressure - Port Jefferson, NY

The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

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Average wind speed
Port Jefferson, NY

Average wind speed - Port Jefferson, NY

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).

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Average humidity
Port Jefferson, NY

Average humidity - Port Jefferson, NY

The months with the highest relative humidity are May and June (77%).
The month with the lowest relative humidity is November (71%).

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Average rainfall
Port Jefferson, NY

Average rainfall - Port Jefferson, NY

The wettest month (with the highest rainfall) is December (3.58").
The driest month (with the least rainfall) is January (2.05").

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Average rainfall days
Port Jefferson, NY

Average rainfall days - Port Jefferson, NY

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).

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Average snowfall
Port Jefferson, NY

Average snowfall - Port Jefferson, NY

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").

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Average snowfall days
Port Jefferson, NY

Average snowfall days - Port Jefferson, NY

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).

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Average sea temperature
Port Jefferson, NY

Average sea temperature - Port Jefferson, NY

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).

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Average daylight / Average sunshine
Port Jefferson, NY

Average daylight / Average sunshine - Port Jefferson, NY

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).

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).

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Average sunshine days
Port Jefferson, NY

Average sunshine days - Port Jefferson, NY

The month with the most sunshine days is November (20.5 days).
The month with the least sunshine days is July (13 days).

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Average UV index
Port Jefferson, NY

Average UV index - Port Jefferson, NY

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).

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Average visibility
Port Jefferson, NY

Average visibility - Port Jefferson, NY

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).

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Port Jefferson, New York, USA

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