Frost dates for Grant, CO
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
June 15
typical year
Safe to plant
June 30
frost is over in 9 of 10 years
First fall frost
September 9
typical year
Growing season
84 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 | – | May 18 – Jun 1 | – |
| Spinach | – | May 4 – 25 | Jul 15 – 29 |
| Lettuce | – | May 18 – Jun 8 | Jul 15 – 29 |
| Radishes | – | May 18 – Jun 29 | Jul 29 – Aug 12 |
| Onions | – | May 18 – Jun 1 | – |
| Potatoes | Season usually too short. Try a quick variety or row covers. | ||
| Carrots | – | May 25 – Jun 15 | Jun 17 – Jul 1 |
| Beets | – | May 18 – Jun 1 | Jul 1 – 15 |
| Kale | Apr 6 – 20 | May 18 – Jun 1 | Jul 1 – 15 |
| Broccoli | Apr 6 – 20 | Jun 1 – 15 | Jul 1 – 15 |
| Cabbage | Mar 23 – Apr 6 | May 18 – Jun 1 | Jul 1 – 15 |
| Garlic | – | – | Jul 29 – Aug 19 |
| Warm-season crops | |||
| Tomatoes | Season usually too short. Try a quick variety or row covers. | ||
| Peppers | Season usually too short. Try a quick variety or row covers. | ||
| Cucumbers | – | Jun 30 – Jul 21 | – |
| Zucchini | – | Jun 30 – Jul 28 | – |
| Pumpkins | Season usually too short. Try a quick variety or row covers. | ||
| Green beans | – | Jun 30 – Jul 1 | – |
| Sweet corn | Season usually too short. Try a quick variety or row covers. | ||
| Basil | May 26 – Jun 9 | Jul 7 – 14 | – |
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 | June 30 | June 15 | June 1 |
| Fall frost before | August 26 | September 9 | September 22 |
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 May 30 (June 12 in a late year), and the first one in fall around September 22.
Where these dates come from
NOAA weather station GRANT, CO US (USC00053530), 1991–2020 climate normals. It's the nearest station for 3 zip codes, all within 10 miles:
80448, 80456, 80475
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.