Frost dates for Boise Lucky Peak Dam, ID
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 30
typical year
Safe to plant
May 18
frost is over in 9 of 10 years
First fall frost
October 22
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 | – | Apr 2 – 16 | – |
| Spinach | – | Mar 19 – Apr 9 | Aug 27 – Sep 10 |
| Lettuce | – | Apr 2 – 23 | Aug 27 – Sep 10 |
| Radishes | – | Apr 2 – May 14 | Sep 10 – 24 |
| Onions | – | Apr 2 – 16 | – |
| Potatoes | – | Apr 9 – 23 | – |
| Carrots | – | Apr 9 – 30 | Jul 30 – Aug 13 |
| Beets | – | Apr 2 – 16 | Aug 13 – 27 |
| Kale | Feb 19 – Mar 5 | Apr 2 – 16 | Aug 13 – 27 |
| Broccoli | Feb 19 – Mar 5 | Apr 16 – 30 | Aug 13 – 27 |
| Cabbage | Feb 5 – 19 | Apr 2 – 16 | Aug 13 – 27 |
| Garlic | – | – | Sep 10 – Oct 1 |
| Warm-season crops | |||
| Tomatoes | Mar 23 – Apr 6 | May 18 – Jun 1 | – |
| Peppers | Mar 16 – 30 | May 25 – Jun 8 | – |
| Cucumbers | – | May 18 – Jun 8 | – |
| Zucchini | – | May 18 – Jun 15 | – |
| Pumpkins | – | May 18 – Jun 8 | – |
| Green beans | – | May 18 – Aug 13 | – |
| Sweet corn | – | May 18 – Jun 15 | – |
| Basil | Apr 13 – 27 | May 25 – Jun 1 | – |
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 18 | April 30 | April 11 |
| Fall frost before | September 30 | October 22 | November 6 |
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 9 (May 3 in a late year), and the first one in fall around November 1.
Where these dates come from
NOAA weather station BOISE LUCKY PEAK DAM, ID US (USC00101018), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 7 miles:
83712
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.