Climate and monthly weather forecast
Princeton, NJ

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An ancient stone building still stands strong in the neat fields and scenic trees of Princeton University, New Jersey
An ancient stone building still stands strong in the neat fields and scenic trees of Princeton University, New Jersey

The climate of Princeton

Princeton, New Jersey, USA has a humid subtropical climate with no dry season. This climate type is pinned as Cfa on the Köppen climate classification, characterized by evenly distributed rainfall throughout the year. In the atmospheric realm of Princeton, temperature fluctuations are apparent. The highest monthly average maximum temperature clocks a reading of 84.7°F (29.3°C) in July, while the lowest average minimum temperature drops to 24.3°F (-4.3°C) in January. Speaking volumes of the variation, it sketches a vivid image of the thermal transition from freezing to hot conditions within the span of a year.

Rainfall figures also navigate a dynamic course, fluctuating from 0.67" (17mm) in September to 1.69" (43mm) in July. In the same vein, the number of rainfall days varies from 6.1 in January to 13.9 in July, making July the wettest month in terms of both volume and frequency. March logs an average of 1.42" (36mm) of snow, the highest all year whereas no snowfall is typically recorded between May and October. The daylight duration ranges between 9.3 hours in December to 15 hours in June.

Humidity maintains a steady rhythm, with relative humidity fluctuating slightly from a low of 73% in April to a peak of 79% in October. Sunshine hours vary distinctly throughout the year, with July boasting the highest number of 10.5 hours, and February the lowest, racking up an average of 4.8 hours. Overall, the climatic features of Princeton present it as a land of diverse weather patterns packed into a calendar year.

The best time to visit Princeton

Based on the climatological data, the most favorable time to visit Princeton would be from May to September. The average temperatures during these months are comfortably warm, ranging from 60.4°F (15.8°C) to 84.7°F (29.3°C). These months offer generous daylight, between 13.3 to 14.7 hours, maximizing available outdoor time and activities. September stands out with the lowest average rainfall of 0.67" (17mm), which combined with relevantly moderate temperatures and optimal daylight makes it a prime month for traveling.

The worst time to visit Princeton

The winter months of December to February may prove to be less appealing to those planning a trip to Princeton. These months bring with them the coldest average temperatures, varying from 24.3°F (-4.3°C) to 39.9°F (4.4°C). November ushers in the start of snowfall season extending to March, presenting slippery road conditions and frosty temperatures. Together with the shortest duration of daylight, spanning from 9.3 to 10.7 hours, these conditions may deter outdoor activities and sightseeing.

Spring weather in Princeton

Spring in Princeton, from March to May, is a season of temperature revival as the cold winter months make way for warmer weather. An increase in average temperatures from 33.3°F (0.7°C) to 70.5°F (21.4°C) is registered, while rainfall similarly escalates from 1.06" (27mm) to 1.22" (31mm). On the other hand, snowfall dwindles, with 1.42" (36mm) recorded in March and a negligible amount measured in May.

Summer weather in Princeton

Influenced by the humid subtropical climate, Princeton experiences hot summers between June and August, with average temperatures oscillating between 78.4°F (25.8°C) and 84.7°F (29.3°C). Relative humidity is also on the higher side, ranging from 75-77%. Yet, despite the high temperature threshold, these months bear witness to more daylight, with an average duration of 14.7 to 15 hours.

Autumn weather in Princeton

Autumn, as witnessed from September to November, ushers in a cooling phase. Average temperatures tumble from 75.7°F (24.3°C) to 51.8°F (11°C) as autumn progresses. This period sees a mix of weather, with rainfall dropping from 1.5" (38mm) in September to 0.91" (23mm) in November, and snowfall making a comeback in November at 0.2" (5mm).

Winter weather in Princeton

Winter descends on Princeton from December to February, with temperatures plunging to their lowest all year, ranging between 24.3°F (-4.3°C) to 39.9°F (4.4°C). Snowfall peaks in January at 0.94" (24mm), adding to the frosty charm. Despite the cold, there is little rainfall, as the monthly average shifts between 0.83" (21mm) and 1.26" (32mm) during this season.

Weather in January

As the year begins in Princeton, New Jersey, there's a chilling start with temperatures peaking at 36.9°F (2.7°C) and plummeting to a biting 24.3°F (-4.3°C). This is indeed the coldest period making it necessary to get the winter gear ready. Weather in January »

Weather in February

Transitioning from January to February, Princeton experiences a slight rise in temperature. The clouds, however, cloak sunlight to a greater extent than the preceding month. Scattered snowfalls continue to make their presence, albeit infrequently. Weather in February »

Weather in March

March heralds the arrival of spring, offering a respite from winter's cold in Princeton. Weather conditions become slightly wetter with 1.06" (27mm) of rain and 9.8 days of rainfall. The temperature begins to climb, reducing the frequency of snowfall. Weather in March »

Weather in April

In Princeton, April is synonymous with increased temperature, reduced snowfall, and the full bloom of spring. Strong winds blow less frequently, and the sky booms with greater daylight, impacting visibility positively. It combines increased temperatures and sustained periods of sunshine that creates an inviting outdoor environment. Weather in April »

Weather in May

May sees a significant soar in temperature, heralding the onset of summer in Princeton. While the rainfall slightly increases from previous months, totaling 1.22" (31mm). The rising mercury and amplifying sunlight duration attune to the summer rhythm. Weather in May »

Weather in June

June in Princeton represents the full onset of summer, with longer daylight hours and higher UV index than preceding months. The month displays high temperature interspersed with mild rain, ensuring a balmy weather conducive to outdoor activities. Weather in June »

Weather in July

July stands as the warmest month in Princeton, with an astounding peak temperature of 84.7°F (29.3°C). Alongside the heat, it also registers the highest amount of rainfall leading to humid days. The kicked-up humidity, combined with soaring temperatures, paves the way for occasional summer showers. Weather in July »

Weather in August

August arrives with a slight dip in temperature compared to July. Yet, it shares a similar weather pattern alongside a slight reduction in daylight hours. The decrease in temperature creates a soft transition from summer's peak to a mild end, retaining the essence of summertime. Weather in August »

Weather in September

With a further decline in temperatures, September starts to blend summer's residue with the touch of incoming fall. The onset of autumn, in Princeton, is characterized by mild temperatures coupled with a sprinkling of rain. The daylight duration contracts, and the sky radiates less sunshine, rendering a russet tone to the surroundings. Weather in September »

Weather in October

October in Princeton is utterly autumnal, with temperatures making a noticeable dip from September's mild warmth. The shortening daylight hours and the crimson Autumn leaves paint a picturesque backdrop. With the retreat of summer, the wind speed picks up, contributing to the overall feel of the season. Weather in October »

Weather in November

November in Princeton is marked by a further decrease in temperature, lesser daylight hours, and the onset of early snowfall. The prevalent weather ensembles a pre-winter pattern with variable weather conditions. Rainfall remains nearly consistent with the previous month, while cloud coverage increases against the waning daylight. Weather in November »

Weather in December

December manifests the return of winter to Princeton, complete with shorter days and frigid temperatures. The month also sees an increase in snowfall, setting the stage for the white Christmas just in line with the festive spirit. Weather in December »
Updated: Aug 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the coldest months?

Princeton's coldest temperatures are experienced in January, with average high temperatures of 36.9°F (2.7°C) and lows of 24.3°F (-4.3°C).

How much does it rain in Princeton?

In Princeton, during the entire year, the rain falls for 119.3 days and collects up to 12.72" (323mm) of precipitation.

When does it snow?

January through May, November and December are months with snowfall.

How much does it snow?

Throughout the year, there are 16.4 snowfall days, and 4.41" (112mm) of snow is accumulated.

What are the months with the lowest UV index?

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

What is the month with the least sunshine?

With an average of 4.8h of sunshine, February has the least sunshine of the year.

When does it snow the most?

March is the month with the most snowfall. Snow falls for 3.7 days and accumulates 1.42" (36mm) of snow.

When is Daylight Saving Time (DST)?

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.

What is the least humid month in Princeton?

April is the least humid month, with an average relative humidity of 73%.

When it does not snow?

June through October are months without snowfall in Princeton.

When are the longest days?

June has the longest days of the year, with an average of 15h and 0min of daylight.

What is the month with the highest UV index?

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

What time of the year is the hottest?

July is the warmest month, with the temperature often reaching an average high of 84.7°F (29.3°C) and an average low of 66.9°F (19.4°C).

What is the wettest month?

The month with the most rainfall is July, when the rain falls for 13.9 days and typically aggregates up to 1.69" (43mm) of precipitation.

What month has the most sunshine?

The month with the most sunshine is July, with an average of 10.5h of sunshine.

What is the driest month?

The month with the least rainfall in Princeton is September, when the rain falls for 10 days and typically collects 0.67" (17mm) of precipitation.

What is the most humid month?

The most humid month is October, with an average relative humidity of 79%.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 24min of daylight.

Average temperature
Princeton, NJ

Average temperature - Princeton, NJ

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (36.9°F).

The month with the highest average low temperature is July (66.9°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).

Average pressure
Princeton, NJ

Average pressure - Princeton, NJ

The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed
Princeton, NJ

Average wind speed - Princeton, NJ

The windiest month (with the highest average wind speed) is March (8.8mph).
The calmest month (with the lowest average wind speed) is August (5.4mph).

Average humidity
Princeton, NJ

Average humidity - Princeton, NJ

The month with the highest relative humidity is October (79%).
The month with the lowest relative humidity is April (73%).

Average rainfall
Princeton, NJ

Average rainfall - Princeton, NJ

The wettest month (with the highest rainfall) is July (1.69").
The driest month (with the least rainfall) is September (0.67").

Average rainfall days
Princeton, NJ

Average rainfall days - Princeton, NJ

The month with the highest number of rainy days is July (13.9 days).
The month with the least rainy days is January (6.1 days).

Average snowfall
Princeton, NJ

Average snowfall - Princeton, NJ

The month with the highest snowfall is March (1.42").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days
Princeton, NJ

Average snowfall days - Princeton, NJ

The month with the highest number of snowfall days is January (4.6 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

Average daylight / Average sunshine
Princeton, NJ

Average daylight / Average sunshine - Princeton, NJ

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).

The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).

Average sunshine days
Princeton, NJ

Average sunshine days - Princeton, NJ

The month with the most sunshine days is January (21.8 days).
The month with the least sunshine days is July (13.3 days).

Average UV index
Princeton, NJ

Average UV index - Princeton, NJ

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
Princeton, NJ

Average cloud cover - Princeton, NJ

The months with the most cloud cover are February, March and December (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 33).

Average visibility
Princeton, NJ

Average visibility - Princeton, NJ

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

Princeton, New Jersey, USA

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