Mountainside, NJ Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Mountainside, a borough in Union County, New Jersey.
Today
83°F
Mostly Sunny
Mostly sunny, with a high near 83. East wind around 3 mph.
7-day forecast for Mountainside
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 83°F | Mostly Sunny | 3 mph E | 0% |
| Tonight | 65°F | Mostly Cloudy | 3 mph NW | 4% |
| Wednesday | 82°F | Partly Sunny then Chance Showers And Thunderstorms | 2 to 6 mph E | 40% |
| Wednesday Night | 70°F | Chance Showers And Thunderstorms | 5 mph S | 33% |
| Thursday | 88°F | Slight Chance Rain Showers then Chance Showers And Thunderstorms | 3 to 8 mph SW | 41% |
| Thursday Night | 72°F | Chance Showers And Thunderstorms then Partly Cloudy | 3 to 7 mph SW | 43% |
| Friday | 89°F | Mostly Sunny then Chance Showers And Thunderstorms | 3 to 7 mph SW | 45% |
| Friday Night | 71°F | Chance Showers And Thunderstorms | 6 mph SW | 44% |
| Saturday | 86°F | Partly Sunny then Chance Showers And Thunderstorms | 3 to 8 mph W | 38% |
| Saturday Night | 70°F | Chance Showers And Thunderstorms | 3 to 7 mph W | 38% |
| Sunday | 87°F | Mostly Sunny | 3 to 7 mph W | 13% |
| Sunday Night | 71°F | Mostly Clear | 6 mph SW | 13% |
| Monday | 89°F | Mostly Sunny | 5 to 10 mph W | 10% |
| Monday Night | 71°F | Partly Cloudy | 5 to 9 mph W | 12% |
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 Aug 4, 2026.