Frost dates for Mount Horeb, 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 7
typical year
Safe to plant
May 22
frost is over in 9 of 10 years
First fall frost
October 1
typical year
Growing season
148 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 9 – 23 | – |
| Spinach | – | Mar 26 – Apr 16 | Aug 6 – 20 |
| Lettuce | – | Apr 9 – 30 | Aug 6 – 20 |
| Radishes | – | Apr 9 – May 21 | Aug 20 – Sep 3 |
| Onions | – | Apr 9 – 23 | – |
| Potatoes | – | Apr 16 – 30 | – |
| Carrots | – | Apr 16 – May 7 | Jul 9 – 23 |
| Beets | – | Apr 9 – 23 | Jul 23 – Aug 6 |
| Kale | Feb 26 – Mar 12 | Apr 9 – 23 | Jul 23 – Aug 6 |
| Broccoli | Feb 26 – Mar 12 | Apr 23 – May 7 | Jul 23 – Aug 6 |
| Cabbage | Feb 12 – 26 | Apr 9 – 23 | Jul 23 – Aug 6 |
| Garlic | – | – | Aug 20 – Sep 10 |
| Warm-season crops | |||
| Tomatoes | Mar 27 – Apr 10 | May 22 – Jun 5 | – |
| Peppers | Mar 20 – Apr 3 | May 29 – Jun 12 | – |
| Cucumbers | – | May 22 – Jun 12 | – |
| Zucchini | – | May 22 – Jun 19 | – |
| Pumpkins | – | May 22 – Jun 12 | – |
| Green beans | – | May 22 – Jul 23 | – |
| Sweet corn | – | May 22 – Jun 19 | – |
| Basil | Apr 17 – May 1 | May 29 – Jun 5 | – |
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 22 | May 7 | April 22 |
| Fall frost before | September 18 | October 1 | October 16 |
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 27 (May 13 in a late year), and the first one in fall around October 12.
Towns that use these dates
This is the nearest NOAA station with frost records for 5 towns.
Mount Horeb, Mazomanie, Black Earth, Arena, Blue Mounds
Where these dates come from
NOAA weather station MAZOMANIE WWTP, WI US (USC00475189), 1991–2020 climate normals. It's the nearest station for 5 zip codes, all within 15 miles:
53503, 53515, 53517, 53560, 53572
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.