Iselin, NJ Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Iselin, a community in Middlesex County, New Jersey.
This Afternoon
72°F
Mostly Sunny
Mostly sunny, with a high near 72. Southeast wind around 5 mph.
7-day forecast for Iselin
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 72°F | Mostly Sunny | 5 mph SE | 1% |
| Tonight | 60°F | Mostly Cloudy | 5 mph SE | 4% |
| Sunday | 73°F | Rain Showers | 5 to 10 mph S | 86% |
| Sunday Night | 58°F | Showers And Thunderstorms | 5 to 10 mph W | 75% |
| Monday | 68°F | Chance Rain Showers | 5 to 10 mph N | 39% |
| Monday Night | 54°F | Chance Rain Showers | 5 to 10 mph NE | 26% |
| Tuesday | 63°F | Chance Rain Showers | 10 to 15 mph NE | 31% |
| Tuesday Night | 52°F | Chance Rain Showers | 10 to 15 mph NE | 27% |
| Wednesday | 64°F | Slight Chance Rain Showers | 15 mph NE | 24% |
| Wednesday Night | 52°F | Chance Rain Showers | 15 mph NE | 31% |
| Thursday | 63°F | Chance Rain Showers | 15 mph NE | 33% |
| Thursday Night | 51°F | Chance Rain Showers | 10 to 15 mph NE | 36% |
| Friday | 65°F | Chance Rain Showers | 10 to 15 mph N | 34% |
| Friday Night | 52°F | Chance Rain Showers | 10 to 15 mph N | 31% |
Forecast source: National Weather Service (api.weather.gov) for Iselin (40.570, -74.316). Updated through the day.
Growing snapshot for Iselin
Last spring frost
Apr 11
First fall frost
Oct 28
Growing season
198 days
Hardiness zone
7a
More local growing data for Iselin: nearby ZIP 08830 weather · frost dates · planting calendar · New Jersey frost dates
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Climate data from the nearest NOAA station, Plainfield, Nj (5.1 mi from Iselin). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.