Iselin, New Jersey Weather
Solstice approaches — longest light. Day 88 of spring. Read this microseason across nine climate regions →
Iselin weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 15Drizzle93%0.06″79°66°—
- TuesdayJun 16Overcast——79°57°0°
- WednesdayJun 17Light Drizzle23%0.01″83°59°+4°
- ThursdayJun 18Light Drizzle48%—94°70°+11°
- FridayJun 19Light Drizzle27%0.02″86°68°-8°
- SaturdayJun 20Partly Cloudy16%—81°62°-5°
- SundayJun 21Overcast——83°61°+2°
AQI 34 (Good), driven by Ozone. AQI down 11 over the last 6 hours (gradual decline). Ozone at AQI 36 now. With UV 8.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 40 around 1 PM.
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 36 now. With UV 8.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 40 around 1 PM.
- Present
- AQI 36
- UV peak
- 8.3 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 40
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).








































A summer fog for fair, a winter fog for rain.
- Moonrise
- 5:25 AM
- Moonset
- 8:44 PM
- In sign
- ♋︎ Cancer
Solstice approaches — longest light
Iselin at a glance
- Today vs. normal: 73°F — typical for the season
- Last frost: April 19 (climatological average for this latitude)
- Microseason: Jun 11–15
- Planting window: Stake and prune tomato suckers. Watch for squash vine borers.
16-Day Forecast — Iselin
- Mon79°66°93%
- Tue79°57°0%
- Wed83°59°23%
- Thu94°70°48%
- Fri86°68°27%
- Sat81°62°16%
- Sun83°61°5%
- Mon69°59°29%
- Tue81°57°29%
- Wed81°60°16%
- Thu80°62°13%
- Fri79°61°23%
- Sat89°63°19%
- Sun88°70°18%
- Mon100°74°27%
- Tue95°72°32%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of June 15, 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.
Microseason · June 11–15
Solstice approaches — longest light
Sunrise before 5:30 AM; sunset nearly 8:30 PM.
Day 166 of 365 · Wedge 33 of 72
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
Iselin peaks at about 77°F in July and bottoms near 30°F in January; December brings the heaviest rain (4.2 inches) and February the least (3.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 30° | 3.4″ | 14 |
| February | 32° | 3.0″ | 13 |
| March | 41° | 3.7″ | 15 |
| April | 52° | 3.9″ | 17 |
| May | 61° | 3.7″ | 18 |
| June | 70° | 3.8″ | 17 |
| July | 77° | 3.5″ | 16 |
| August | 75° | 4.0″ | 17 |
| September | 69° | 3.6″ | 13 |
| October | 58° | 3.1″ | 11 |
| November | 44° | 3.7″ | 13 |
| December | 35° | 4.2″ | 13 |
Regional context
Per NOAA NCEI 1991-2020 normals, Iselin runs from a 30°F January mean to 77°F in July, a 46°F seasonal spread, with near 43.6 inches of precipitation across about 175 wet days.
Rainfall in Iselin stays even across the calendar: December tops out at 4.2 inches over 13.3 rainy days, and February still logs 3.0 inches across 12.5 — a narrow range for Iselin. That lines Iselin up with places like Menlo Park Terrace, NJ, Colonia, NJ and Fords, NJ, fed by overlapping storm tracks.
Around mid-April, Iselin sheds its freezing nights — peas, lettuce, spinach, and radishes go into Iselin's beds. Heat-demanding starts go out a fortnight on in Iselin, after the soil warms and cold snaps clear. The season ends by mid-November in Iselin, once hard frosts set back in. Iselin's low ground holds frost later into spring than Iselin's benches, which run 3-5 days ahead.
Similar climates: Menlo Park Terrace, NJ, Colonia, NJ, Fords, NJ, Avenel, NJ, Metuchen, NJ.
Frequently asked
- When does it freeze in Iselin?
- Frost typically leaves Iselin by mid-April and returns to Iselin near mid-November.
- What is the rainy season in Iselin?
- Iselin sees its heaviest rain in December (around 4.2 inches), part of roughly 44 inches a year.
- What is the warmest month in Iselin?
- The warmest stretch in Iselin comes in July, around 77°F on average.
- What is the coldest month in Iselin?
- On average January is the chilliest month in Iselin, about 30°F.
- When can I start a vegetable garden in Iselin?
- Frost-hardy sowings begin at mid-April in Iselin; warm-season starts follow two weeks on.
- How many rainy days does Iselin get?
- Iselin records around 175 days of measurable precipitation annually.
- What hardiness zone is Iselin?
- Iselin's USDA zone comes from its January mean (30°F); enter the ZIP on the USDA lookup for the number.
- What is the 10-day forecast for Iselin?
- Iselin'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 Iselin?
- See this week's day-by-day rain chances for Iselin in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Iselin?
- Current conditions for Iselin and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Iselin forecast updated?
- The Iselin forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Iselin?
- Day length in Iselin peaks around the June solstice — earliest sunrise and latest sunset — and is shortest near the December solstice.
- How accurate is the weather forecast for Iselin?
- The next few days in Iselin's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Iselin, New Jersey occupies a warm-summer humid continental zone, with January means near 30°F and July around 77°F — a 47°F swing.
Across the year, Iselin collects about 44 inches of precipitation over roughly 175 days with measurable rain or snow.
Latitude 40.6°N gives Iselin its 47°F swing, and with it the rhythm of Iselin's growing season.
Beaches near Iselin
- Jacob Riis Beach23.2 mi
- Rockaway Beach Beach25.3 mi
Each linked page shows live water temperature, wave height, swim and surf verdicts, tides, and rip-current risk from NDBC + NOAA + NWS data.
ZIP codes in Iselin
- 08830