Mountainside, NJ Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Mountainside, a borough in Union County, New Jersey.
This Afternoon
71°F
Partly Sunny
Partly sunny, with a high near 71. Southeast wind around 6 mph.
7-day forecast for Mountainside
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 71°F | Partly Sunny | 6 mph SE | 1% |
| Tonight | 59°F | Mostly Cloudy then Slight Chance Rain Showers | 6 mph SE | 17% |
| Sunday | 72°F | Rain Showers then Rain Likely | 8 mph SE | 87% |
| Sunday Night | 57°F | Rain Likely then Rain Showers Likely | 5 to 12 mph W | 81% |
| Monday | 67°F | Slight Chance Rain Showers | 7 to 12 mph NE | 24% |
| Monday Night | 53°F | Chance Rain Showers | 7 to 10 mph NE | 30% |
| Tuesday | 63°F | Chance Rain Showers | 12 mph NE | 30% |
| Tuesday Night | 51°F | Chance Rain Showers then Mostly Cloudy | 9 to 14 mph NE | 30% |
| Wednesday | 63°F | Mostly Cloudy then Slight Chance Rain Showers | 15 mph NE | 19% |
| Wednesday Night | 51°F | Slight Chance Rain Showers | 15 mph NE | 21% |
| Thursday | 62°F | Chance Rain Showers | 15 mph NE | 28% |
| Thursday Night | 50°F | Chance Rain Showers | 13 to 16 mph NE | 34% |
| Friday | 64°F | Chance Rain Showers | 12 to 17 mph N | 35% |
| Friday Night | 52°F | Chance Rain Showers | 15 mph N | 35% |
Forecast source: National Weather Service (api.weather.gov) for Mountainside (40.681, -74.360). Updated through the day.
Growing snapshot for Mountainside
Last spring frost
Apr 11
First fall frost
Oct 31
Growing season
202 days
Hardiness zone
7a
More local growing data for Mountainside: nearby ZIP 07092 weather · frost dates · planting calendar · New Jersey frost dates
Nearby towns & communities
Chatham
Connecticut Farms
Cranford
Elizabeth
Fanwood
Garwood
Kean University
Kenilworth
Linden
New Providence
North Plainfield
Plainfield
Rahway
Roselle
Roselle Park
Summit
Union
Vauxhall
Westfield
Climate data from the nearest NOAA station, Cranford, Nj (2.1 mi from Mountainside). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 20, 2026.