Weather StoryAlmanac, microseasons, and the day's weather story.

Princeton, New Jersey Weather

Cicadas claim the afternoon. Day 15 of summer. Read this microseason across nine climate regions →

Princeton weather forecast — hour by hour, 7-day outlook, NOAA radar

Princeton, NJ
Sunday, July 5 at 4:29 PM
86
°
Partly Cloudy
Feels like
94°
Humidity
66%
Wind
4 mph
Sunrise
1:34 AM
Sunset
4:31 PM
Princeton, NJ
Hour by hour · 24h
24-Hour ForecastPrinceton, NJ: 24-hour forecast. Temperatures range from 70 to 86 degrees Fahrenheit with a 56% chance of precipitation at 1 AM.
L 70°H 86°
Princeton, NJ
7-day forecast
  1. Today
    Jul 5
    Heavy Drizzle
    70%
    0.04″
    86°73°—
  2. Monday
    Jul 6
    Heavy Rain
    56%
    1.2″
    74°67°-12°
  3. Tuesday
    Jul 7
    Light Drizzle
    65%
    0.02″
    68°63°-6°
  4. Wednesday
    Jul 8
    Overcast
    39%
    —
    84°59°+16°
  5. Thursday
    Jul 9
    Drizzle
    23%
    —
    86°66°+2°
  6. Friday
    Jul 10
    Overcast
    36%
    —
    85°69°-1°
  7. Saturday
    Jul 11
    Foggy
    35%
    —
    85°64°0°
Princeton, NJ
Next 24 hours · Warm now
HOT 90°66°78°90°12p6p12a6anow 86°high 86°low 70°PRECIP %
Princeton, NJ
Anemometer · 24h winds · from true
NESW
From · True
NE
038° · veering 112°
Direction
NE
038°
Sustained
4
mph
Gust
6
mph
Peak 24h
26
avg 5
Beaufort · 2 · LIGHT BRZ
0
CALM
<1
1
LIGHT AIR
1–3
2
LIGHT BRZ
4–7
3
GENTLE BRZ
8–12
4
MOD BRZ
13–18
5
FRESH BRZ
19–24
6
STRONG BRZ
25–31
7
NEAR GALE
32–38
24h · sust vs gust · mph
avg 5 · pk 26 @ 11:00p
0102030MPHB1B2B3B4B5B6-21h-18h-15h-12h-9h-6h-3h-24hNOWpk 2412SUSTGUST
−24h−18h−12h−6hnow
A whisper of wind — leaves barely shift on the trees.
Princeton, NJ
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
1008.4
-0.6 mb in 3h · falling · 29.78 inHg
Now
1008.4
mb
3h
-0.6
mb
12h
+1.5
mb
24h
+3.0
mb
Regime · RAIN
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 1005–1010
1000STORM|RAIN10051010RAIN|CHG1015CHG|FAIR-21h-18h-15h-12h-9h-6h-3h-24hNOW1010.21004.71008.4
−24h−18h−12h−6hnow
Damp, unsettled regime — wet weather lingers nearby.
Princeton, NJ
Air quality
77
AQI
Moderate
↑+38 in 6h▲Peak ~116 @ 11 PM

AQI 77 (Moderate), driven by Ozone. AQI up 38 in the last 6 hours — air quality is degrading. Ozone at AQI 124 — peak already passed at 1 PM under partly cloudy skies. Levels should ease through evening.

OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.

PM 2.5Moderate
13.2μg/m³
PM 10Good
14μg/m³
NO₂Good
3μg/m³
OzoneDRIVERUnhealthy
152μg/m³
UV IndexLow
0.8

What's driving it

Ozone × UV × Sky

Ozone at AQI 124 — peak already passed at 1 PM under partly cloudy skies. Levels should ease through evening.

Present
AQI 124
UV peak
0.7 at earlier today
Sky at peak
partly cloudy
Projected peak
AQI 124

PM × Wind × Precip

PM2.5 at 13.2 µg/m³ (AQI 59) with a 0.93 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust.

PM2.5/PM10
0.93
Wind
calm
Recent rain
0h in last 6h
Pattern
stagnant smoke

Trends

Seven days of AQI and PM2.5.

Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).

7-DAY AQI TREND50100SUNMONTUEWEDTHUFRISATSUN7-DAY PM2.5 TREND · μg/m³420
Princeton, NJ
Sky cover · visibility · 24h
Cloud cover
78%
MOSTLY CLOUDY
100%0%−24h−18h−12h−6hnow
Visibility
50.4mi
UNLIMITED
128 mi0 mi−24h−18h−12h−6hnow
Earth · GOES-19 ABI
Full Disk · Visible · GeoColor
GOES-19 full disk Visible · GeoColor
True-color daytime, blue/IR sandwich at night
20:29 UTC · Princeton, NJ · NOAA NESDIS / STAR · up to 10848 px
Continental US · GOES-19 ABI
CONUS Sector · Visible · GeoColor
GOES-19 CONUS Visible · GeoColor
Daytime true-color, blue-light/IR sandwich at night
20:29 UTC · Princeton, NJ · NOAA NESDIS / STAR · 5-min cadence · up to 10000 px
Princeton, NJ
Satellite · infrared · animated
Princeton, NJ
Loading IR frames…
IR · cloud-top temp© RainViewer · Carto
Princeton, NJ
Almanac · Sunday, July 5
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
Civil dawn
5:02 AM
Sunrise
1:34 AM
Daylight
14h 57m
Sunset
4:31 PM
Civil dusk
9:05 PM
Planting note
Harvest early potatoes. Begin drying onions on the surface.
Princeton, NJ
The moon
Waning Gibbous
69% illuminated
Moonrise
11:16 PM
Moonset
11:08 AM
In sign
♓︎ Pisces
Princeton, NJ
Microseason
Jul 1–5

Cicadas claim the afternoon

fish
Jan 151% of the yearDec 31

Read this microseason across nine climate regions →

Princeton at a glance

  • Today vs. normal: 15°F above the seasonal normal for this latitude
  • Last frost: April 18 (climatological average for this latitude)
  • Microseason: Jul 1–5
  • Planting window: Harvest early potatoes. Begin drying onions on the surface.

ZIP codes: 08540, 08542, 08544

16-Day Forecast — Princeton

  1. Sun86°73°70%
  2. Mon74°67°56%
  3. Tue68°63°65%
  4. Wed84°59°39%
  5. Thu86°66°23%
  6. Fri85°69°36%
  7. Sat85°64°35%
  8. Sun80°63°22%
  9. Mon88°66°17%
  10. Tue75°65°14%
  11. Wed78°65°17%
  12. Thu78°61°32%
  13. Fri90°62°24%
  14. Sat86°65°23%
  15. Sun78°68°23%
  16. Mon70°65°29%

Forecast data from Open-Meteo (CC BY 4.0).

Right now in the garden

Peak growing season

As of July 5, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.

SPC Convective Outlook

Storm Prediction Center — Princeton

SPC has placed Princeton in the Slight Risk category for severe thunderstorms today.

  • TODAYSLGTSlight Risk
  • TOMORROWTSTMGeneral Thunderstorms
  • DAY 3NONENo severe risk

Scattered severe storms possible. A few tornadoes, hail, and damaging wind gusts possible.

Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.

January 1–5: The year turns in silence.January 6–10: Ice thickens on still water.January 11–15: Shortest shadows lengthen.January 16–20: Pheasants begin to call.January 21–25: Springs begin to thaw.January 26–31: Chickadees announce dawn.February 1–5: East wind softens the frost.February 6–10: Sap begins to rise.February 11–15: First snowdrops appear.February 16–20: Red-winged blackbirds return.February 21–25: Rain begins to replace snow.February 26–28: Skunk cabbage pushes through ice.March 1–5: Ice withdraws from the reservoir.March 6–10: Crocuses open to weak sun.March 11–15: Peepers call from the marsh.March 16–20: Woodcocks spiral at dusk.March 21–25: Equinox — light overtakes dark.March 26–31: Forsythia opens along the fences.April 1–5: Cherry blossoms drift like snow.April 6–10: Warblers appear in the understory.April 11–15: Magnolias bloom and fall in a day.April 16–20: Dogwoods float above the forest.April 21–25: Lilacs perfume the evening.April 26–30: Last frost releases the garden.May 1–5: Warblers flood the Ramble.May 6–10: Tulip poplars light their candles.May 11–15: Shad run up the rivers.May 16–20: Roses open along the stoops.May 21–25: Firefly scouts appear at dusk.May 26–31: Strawberries ripen in the sun.June 1–5: Fireflies rise from the lawn.June 6–10: Elderflowers open in hedgerows.June 11–15: Solstice approaches — longest light.June 16–20: Honeysuckle sweetens the night.June 21–25: Solstice — the sun stands still.June 26–30: Lightning bugs drift through oaks.July 1–5: Cicadas claim the afternoon.July 6–10: Queen Anne's lace lines the roads.July 11–15: Thunder builds each afternoon.July 16–20: Corn reaches for the tassels.July 21–25: Dog days settle in the haze.July 26–31: Katydids begin their chorus.August 1–5: Night falls a minute earlier.August 6–10: Sunflowers face the morning.August 11–15: Goldenrod begins to bloom.August 16–20: Crickets pulse through warm nights.August 21–25: First cool morning surprises.August 26–31: Monarchs stage for flight.September 1–5: School buses reappear.September 6–10: Asters purple the roadsides.September 11–15: Hawk migration over the Hudson.September 16–20: Equinox — dark overtakes light.September 21–25: Apples hang heavy on the branch.September 26–30: Geese begin to chevron south.October 1–5: Witch hazel blooms as others fade.October 6–10: Maples begin to blaze.October 11–15: Frost paints the garden black.October 16–20: Oaks turn bronze and russet.October 21–25: Leaves rattle down the gutters.October 26–31: Clocks fall back — dusk at five.November 1–5: Ginkgos drop overnight.November 6–10: Last leaves cling stubbornly.November 11–15: Juncos arrive from the north.November 16–20: Bare branches reveal the sky.November 21–25: First flurries dust the rooftops.November 26–30: Woodsmoke curls through the block.December 1–5: Darkness settles before dinner.December 6–10: Holly and winterberry persist.December 11–15: Shortest day approaches.December 16–20: Ice begins to form at the edges.December 21–25: Solstice — the sun begins return.December 26–31: The year turns in silence.🌱February 14 — First skunk-cabbage spathes thaw their way up☀️March 20 — Spring equinox — day and night balance🌸April 5 — Cherry blossoms peak in the parks🐦May 10 — Warbler migration peaks along the coast✨May 25 — First fireflies scout the meadows at dusk🌞June 21 — Summer solstice — longest day🦗July 25 — Peak cicada chorus in the afternoons🌊August 18 — Warmest sea-surface temperatures of the year🍂September 22 — Autumn equinox — the slow turn❄️October 25 — First widespread frost in the suburbs🍁November 10 — Peak leaf color across the Hudson Valley🌙December 21 — Winter solstice — longest night

Microseason · July 1–5

Cicadas claim the afternoon

Annual cicada buzz begins, peaking in the heat of the day.

Day 186 of 365 · Wedge 37 of 72

The solar year drawn as a wheel of 72 five-day windows. Each wedge is one microseason; the four colored arcs mark winter, spring, summer, and autumn; the small icons sit at notable phenological events. The crimson pointer creeps clockwise as the year turns.

Planting calendar

MonthPlantHarvest
January——
February——
March——
Aprillettuce, peas, spinach, radishes—
Maylettuce, peas, spinach, radishes, tomatoes, peppers, beans, squashlettuce, peas, radishes
Junetomatoes, peppers, beans, squashlettuce, peas, radishes
Julytomatoes, peppers, beans, squashtomatoes, beans, summer squash
August—tomatoes, beans, summer squash
Septemberfall brassicas, garlic (overwinter), carrotstomatoes, beans, summer squash
Octoberfall brassicas, garlic (overwinter), carrotswinter squash, tomatoes (last)
November——
December——

A year in weather

In Princeton, July runs warmest near 77°F and January coldest around 31°F, while August is the wettest month (4.2 inches) and October the driest (3.0 inches).

MonthMean tempPrecipRainy days
January31°3.5″13
February33°3.1″12
March42°3.8″15
April53°4.0″16
May61°3.7″17
June71°3.8″17
July77°3.8″16
August76°4.2″17
September69°3.7″13
October58°3.0″11
November45°3.7″12
December36°4.2″13

Regional context

Per NOAA NCEI 1991-2020 normals, Princeton runs from a 31°F January mean to 77°F in July, a 46°F seasonal spread, with near 44.4 inches of precipitation across about 173 wet days.

No season owns Princeton's rain: August reaches 4.2 inches across 17.2 days and October keeps 3.0 inches on 10.6, an even spread through Princeton's year. That lines Princeton up with places like Rocky Hill, NJ, Princeton Junction, NJ and Kingston, NJ, fed by overlapping storm tracks.

Princeton reaches its last hard frost near mid-April; that is the cue for peas, lettuce, spinach, and radishes. Tomatoes and peppers do best set out two weeks later in Princeton, once nights clear the mid-40s°F. The season ends by mid-November in Princeton, once hard frosts set back in. Princeton's low ground holds frost later into spring than Princeton's benches, which run 3-5 days ahead.

Similar climates: Rocky Hill, NJ, Princeton Junction, NJ, Kingston, NJ, Blawenburg, NJ, Plainsboro Center, NJ.

Frequently asked

When does it freeze in Princeton?
Princeton's last spring frost lands near mid-April, and in Princeton the first fall frost follows around mid-November.
What is the rainy season in Princeton?
Rainfall in Princeton peaks in August near 4.2 inches, out of about 44 inches annually.
What is the warmest month in Princeton?
The warmest stretch in Princeton comes in July, around 77°F on average.
What is the coldest month in Princeton?
On average January is the chilliest month in Princeton, about 31°F.
When can I start a vegetable garden in Princeton?
Princeton's last frost (mid-April) cues hardy greens; in Princeton, hold heat-lovers two weeks past.
How many rainy days does Princeton get?
Princeton averages about 173 days with measurable rain or snow each year.
What hardiness zone is Princeton?
Princeton sits in the USDA zone set by January lows near 31°F; the USDA ZIP tool gives the band.
What is the 10-day forecast for Princeton?
Princeton's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
Will it rain this week in Princeton?
See this week's day-by-day rain chances for Princeton in the daily forecast above, and the next 24 hours in the hourly chart.
What is the weather like right now in Princeton?
Current conditions for Princeton and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
How often is the Princeton forecast updated?
The Princeton forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
When are sunrise and sunset in Princeton?
Today's sunrise and sunset times for Princeton are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
How accurate is the weather forecast for Princeton?
The next few days in Princeton's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.

Climate

Princeton's warm-summer humid continental climate in New Jersey pairs 31°F Januarys with 77°F Julys, 46°F apart across the seasons.

In a typical year Princeton records about 44 inches of precipitation on around 173 days.

The 46°F gap between Princeton's summer and winter, at 40.4°N, shapes Princeton's frost calendar.

All cities in New Jersey →

Trenton, NJ weather →

ZIP codes in Princeton

  • 08544
  • 08540
  • 08542
  • 08541

Climate normals from the Open-Meteo Climate API. Köppen approximation from NOAA NCEI U.S. Climate Regions. See methodology for data sources, editorial rules, and corrections. Maintainer: Brian Tighe.