Checking current alerts… View NWS forecast and alerts.
Will it freeze in Mountainside in the next 7 nights?
No overnight lows at or below 32°F are forecast in Mountainside during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 61°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM EST to Fri, Nov 6, 6:00 AM EST.
1 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 61°F Above 36°F · Light Rain then Patchy Fog
- Fri, Nov 6 50°F Above 36°F · Chance Light Rain then Partly Cloudy
- Sat, Nov 7 43°F Above 36°F · Partly Cloudy
- Sun, Nov 8 40°F Above 36°F · Mostly Clear
- Mon, Nov 9 38°F Above 36°F · Mostly Clear
- Tue, Nov 10 40°F Above 36°F · Mostly Clear
- Wed, Nov 11 36°F Frost possible · Mostly Clear
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Mountainside
The median first fall hard-freeze date (28°F) is November 12, from NOAA’s 1991–2020 Climate Normals at Cranford. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Apr 10 · Apr 25 · May 11 | Oct 7 · Oct 20 · Nov 4 | 176 days |
| 32°F freeze | Mar 30 · Apr 11 · Apr 28 | Oct 14 · Oct 31 · Nov 15 | 202 days |
| 28°F hard freeze | Mar 14 · Mar 30 · Apr 12 | Oct 27 · Nov 12 · Dec 1 | 228 days |
Average high temperature by month
1991–2020 normals at Cranford
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Mountainside, NJ come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Cranford (station USC00282023, elevation 80 ft), 2.2 mi from Mountainside. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Mountainside
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Westfield, NJ | 2.5 mi | Apr 11 | Oct 31 |
| Summit, NJ | 2.5 mi | Apr 18 | Oct 27 |
| New Providence, NJ | 2.5 mi | Apr 18 | Oct 27 |
| Garwood, NJ | 3.1 mi | Apr 11 | Oct 31 |
| Fanwood, NJ | 3.1 mi | Apr 11 | Oct 28 |
| Kenilworth, NJ | 3.7 mi | Apr 11 | Oct 31 |
| Chatham, NJ | 4.3 mi | Apr 18 | Oct 27 |
| Watchung, NJ | 5.0 mi | Apr 11 | Oct 28 |
| Roselle Park, NJ | 5.0 mi | Apr 11 | Oct 31 |
| Plainfield, NJ | 5.6 mi | Apr 11 | Oct 28 |
Frequently asked questions
When is the last frost in Mountainside?
On average, the last spring frost (32°F) in Mountainside is around April 11. In about 1 year in 10 it comes after April 28, and in 9 years in 10 it comes after March 30.
When is the first frost in Mountainside?
The first fall frost (32°F) usually arrives around October 31. There’s a 10% chance of a freeze by October 14 and a 90% chance by November 15.
Can it frost in Mountainside after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after April 25.
What growing zone is Mountainside?
Mountainside is in USDA Plant Hardiness Zone 7a (average annual extreme minimum temperature 0 to 5°F), based on the 2023 USDA map for ZIP code 07092. See growing zones in New Jersey.
More: all New Jersey frost dates · New Jersey growing zones · frost vs. freeze