Port Jefferson, New York Weather
Fireflies rise from the lawn. Day 78 of spring. Read this microseason across nine climate regions →
Port Jefferson weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Partly Cloudy——81°55°—
- FridayJun 5Overcast——87°60°+6°
- SaturdayJun 6Heavy Drizzle44%—88°63°+1°
- SundayJun 7Heavy Showers44%0.94″78°64°-10°
- MondayJun 8Overcast——76°58°-2°
- TuesdayJun 9Overcast——81°63°+5°
- WednesdayJun 10Partly Cloudy——82°66°+1°
PM2.5 at 12.1 µg/m³, PM10 at 17.0 µg/m³ — typical background levels with no transport signature. AQI up 47 in the last 6 hours — air quality is degrading.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 55. Overcast through the UV peak window (cloud cover ~95%) — afternoon ozone should stay flat.
- Present
- AQI 55
- UV peak
- 0.0 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 7
PM × Wind × Precip
PM2.5 at 12.1 µg/m³, PM10 at 17.0 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.71
- Wind
- breezy
- Recent rain
- 0h in last 6h
- Pattern
- background
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).
The higher the clouds, the finer the weather.
- Moonrise
- 3:54 AM
- Moonset
- 1:54 PM
- In sign
- ♒︎ Aquarius
Fireflies rise from the lawn
Port Jefferson at a glance
- Today vs. normal: 8°F below the seasonal normal for this latitude
- Last frost: April 22 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 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 — Port Jefferson
SPC has placed Port Jefferson in the General Thunderstorms category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWNONENo severe risk
- DAY 3TSTMGeneral Thunderstorms
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
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.
Beaches near Port Jefferson
- Robert Moses Beach24.9 mi
Each linked page shows live water temperature, wave height, swim and surf verdicts, tides, and rip-current risk from NDBC + NOAA + NWS data.