Frost dates for Union Grove, WI
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
May 5
typical year
Safe to plant
May 20
frost is over in 9 of 10 years
First fall frost
October 8
typical year
Growing season
156 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 | – | Apr 7 – 21 | – |
| Spinach | – | Mar 24 – Apr 14 | Aug 13 – 27 |
| Lettuce | – | Apr 7 – 28 | Aug 13 – 27 |
| Radishes | – | Apr 7 – May 19 | Aug 27 – Sep 10 |
| Onions | – | Apr 7 – 21 | – |
| Potatoes | – | Apr 14 – 28 | – |
| Carrots | – | Apr 14 – May 5 | Jul 16 – 30 |
| Beets | – | Apr 7 – 21 | Jul 30 – Aug 13 |
| Kale | Feb 24 – Mar 10 | Apr 7 – 21 | Jul 30 – Aug 13 |
| Broccoli | Feb 24 – Mar 10 | Apr 21 – May 5 | Jul 30 – Aug 13 |
| Cabbage | Feb 10 – 24 | Apr 7 – 21 | Jul 30 – Aug 13 |
| Garlic | – | – | Aug 27 – Sep 17 |
| Warm-season crops | |||
| Tomatoes | Mar 25 – Apr 8 | May 20 – Jun 3 | – |
| Peppers | Mar 18 – Apr 1 | May 27 – Jun 10 | – |
| Cucumbers | – | May 20 – Jun 10 | – |
| Zucchini | – | May 20 – Jun 17 | – |
| Pumpkins | – | May 20 – Jun 10 | – |
| Green beans | – | May 20 – Jul 30 | – |
| Sweet corn | – | May 20 – Jun 17 | – |
| Basil | Apr 15 – 29 | May 27 – Jun 3 | – |
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 20 | May 5 | April 21 |
| Fall frost before | September 27 | October 8 | October 23 |
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 23 (May 10 in a late year), and the first one in fall around October 20.
Towns that use these dates
This is the nearest NOAA station with frost records for 3 towns.
Union Grove, Raymond, Yorkville
Where these dates come from
NOAA weather station UNION GROVE, WI US (USC00478723), 1991–2020 climate normals. It's the nearest station for 4 zip codes, all within 7 miles:
53126, 53139, 53177, 53182
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.