Frost dates for Princeton, NJ
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
April 25
typical year
Safe to plant
May 12
frost is over in 9 of 10 years
First fall frost
October 16
typical year
Growing season
173 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Mar 28 – Apr 11 | – |
| Spinach | – | Mar 14 – Apr 4 | Aug 21 – Sep 4 |
| Lettuce | – | Mar 28 – Apr 18 | Aug 21 – Sep 4 |
| Radishes | – | Mar 28 – May 9 | Sep 4 – 18 |
| Onions | – | Mar 28 – Apr 11 | – |
| Potatoes | – | Apr 4 – 18 | – |
| Carrots | – | Apr 4 – 25 | Jul 24 – Aug 7 |
| Beets | – | Mar 28 – Apr 11 | Aug 7 – 21 |
| Kale | Feb 14 – 28 | Mar 28 – Apr 11 | Aug 7 – 21 |
| Broccoli | Feb 14 – 28 | Apr 11 – 25 | Aug 7 – 21 |
| Cabbage | Jan 31 – Feb 14 | Mar 28 – Apr 11 | Aug 7 – 21 |
| Garlic | – | – | Sep 4 – 25 |
| Warm-season crops | |||
| Tomatoes | Mar 17 – 31 | May 12 – 26 | – |
| Peppers | Mar 10 – 24 | May 19 – Jun 2 | – |
| Cucumbers | – | May 12 – Jun 2 | – |
| Zucchini | – | May 12 – Jun 9 | – |
| Pumpkins | – | May 12 – Jun 2 | – |
| Green beans | – | May 12 – Aug 7 | – |
| Sweet corn | – | May 12 – Jun 9 | – |
| Basil | Apr 7 – 21 | May 19 – 26 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | May 12 | April 25 | April 12 |
| Fall frost before | October 4 | October 16 | October 29 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around April 10 (April 26 in a late year), and the first one in fall around October 28.
Towns that use these dates
This is the nearest NOAA station with frost records for 4 towns.
Princeton, Hightstown, Allentown, Roosevelt
Where these dates come from
NOAA weather station HIGHTSTOWN 2 W, NJ US (USC00283951), 1991–2020 climate normals. It's the nearest station for 19 zip codes, all within 10 miles:
08501, 08510, 08512, 08514, 08520, 08528, 08535, 08536, 08540, 08542, 08544, 08550, 08555, 08561, 08620, 08690, 08691, 08810, 08831
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.