Grover, CO frost dates
Last spring frostMay 14median date
First fall frostSep 26median date
Growing season135 daysfrost-free
Hardiness zone5aZone 5a
How Grover compares
- In 8 years out of 10, the last spring frost in Grover falls between May 4 and May 27, a 23-day window. The first fall frost falls between September 12 and October 8.
- The median last frost is 3 days later than the Colorado median of May 11.
- Its 135-day growing season is longer than 37% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 11 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 176 nights a year at or below 32°F.
- Compared with Cheyenne, WY, 56 km away, the last frost here is 2 days later than there and the growing season is 7 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 4 |
| 50% (median) | May 14 |
| 10% (safe for tender plants) | May 27 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 12 |
| 50% (median) | September 26 |
| 90% (late) | October 8 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Grover, CO
Grover, CO frost dates — last frost May 14, first frost Sep 26, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 19 to Mar 5Transplant outside: Apr 16 to Apr 30
Start indoors: Mar 5 to Mar 19Transplant outside: May 28 to Jun 11
Start indoors: Mar 5 to Mar 19Transplant outside: May 28 to Jun 11
Start indoors: Mar 19 to Apr 2Transplant outside: May 21 to Jun 4
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 23 to May 7Sow outdoors: Apr 16 to May 21Plant for fall: Aug 1 to Aug 29
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 16 to Apr 30Sow outdoors: Apr 16 to Apr 30Plant for fall: Jul 18 to Aug 8
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 30 to May 14Plant for fall: Jun 20 to Jul 11
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 23 to May 7Plant for fall: Jun 20 to Jul 11
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 30 to May 14Plant for fall: Jun 20 to Jul 11
Start indoors: Apr 2 to Apr 16Transplant outside: Jun 4 to Jun 18Sow outdoors: Jun 4 to Jun 18
Start indoors: Apr 2 to Apr 16Transplant outside: May 21 to Jun 4
Sow outdoors: Apr 2 to Apr 23Plant for fall: Jul 4 to Jul 25
Sow outdoors: Apr 2 to Apr 23Plant for fall: Aug 1 to Aug 22
Sow outdoors: Apr 9 to May 21Plant for fall: Aug 15 to Sep 5
Start indoors: Apr 16 to Apr 23Transplant outside: May 28 to Jun 4Sow outdoors: May 21 to Jun 4Plant for fall: Jul 11 to Jul 25
Start indoors: Apr 16 to Apr 23Sow outdoors: May 21 to Jun 4Plant for fall: Jul 18 to Aug 1
Start indoors: Apr 16 to Apr 23Sow outdoors: May 21 to Jun 4
Start indoors: Apr 16 to Apr 23Transplant outside: May 28 to Jun 11
Sow outdoors: Apr 23 to May 21Plant for fall: Jul 4 to Jul 18
Sow outdoors: Apr 23 to May 21Plant for fall: Jul 18 to Aug 1
Sow outdoors: Apr 23 to May 14
Sow outdoors: Apr 30 to May 28Plant for fall: Jul 18 to Aug 1
Sow outdoors: Apr 30 to May 21Plant for fall: Aug 1 to Aug 22
Sow outdoors: May 21 to Jun 11Plant for fall: Jul 11 to Jul 25
Sow outdoors: May 21 to Jun 4
Transplant outside: May 28 to Jun 18
Plant for fall: Sep 12 to Oct 17
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Grover, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 19 – Mar 5 | Apr 16 – Apr 30 | — | — |
| Peppers | Mar 5 – Mar 19 | May 28 – Jun 11 | — | — |
| Eggplant | Mar 5 – Mar 19 | May 28 – Jun 11 | — | — |
| Tomatoes | Mar 19 – Apr 2 | May 21 – Jun 4 | — | — |
| Lettuce | Mar 19 – Apr 2 | Apr 23 – May 7 | Apr 16 – May 21 | Aug 1 – Aug 29 |
| Kale | Mar 19 – Apr 2 | Apr 16 – Apr 30 | Apr 16 – Apr 30 | Jul 18 – Aug 8 |
| Broccoli | Mar 19 – Apr 2 | Apr 30 – May 14 | — | Jun 20 – Jul 11 |
| Cabbage | Mar 19 – Apr 2 | Apr 23 – May 7 | — | Jun 20 – Jul 11 |
| Cauliflower | Mar 19 – Apr 2 | Apr 30 – May 14 | — | Jun 20 – Jul 11 |
| Okra | Apr 2 – Apr 16 | Jun 4 – Jun 18 | Jun 4 – Jun 18 | — |
| Basil | Apr 2 – Apr 16 | May 21 – Jun 4 | — | — |
| Peas | — | — | Apr 2 – Apr 23 | Jul 4 – Jul 25 |
| Spinach | — | — | Apr 2 – Apr 23 | Aug 1 – Aug 22 |
| Radishes | — | — | Apr 9 – May 21 | Aug 15 – Sep 5 |
| Cucumbers | Apr 16 – Apr 23 | May 28 – Jun 4 | May 21 – Jun 4 | Jul 11 – Jul 25 |
| Zucchini & Summer Squash | Apr 16 – Apr 23 | — | May 21 – Jun 4 | Jul 18 – Aug 1 |
| Winter Squash & Pumpkins | Apr 16 – Apr 23 | — | May 21 – Jun 4 | — |
| Melons & Watermelon | Apr 16 – Apr 23 | May 28 – Jun 11 | — | — |
| Carrots | — | — | Apr 23 – May 21 | Jul 4 – Jul 18 |
| Beets | — | — | Apr 23 – May 21 | Jul 18 – Aug 1 |
| Potatoes | — | — | Apr 23 – May 14 | — |
| Swiss Chard | — | — | Apr 30 – May 28 | Jul 18 – Aug 1 |
| Cilantro | — | — | Apr 30 – May 21 | Aug 1 – Aug 22 |
| Green Beans | — | — | May 21 – Jun 11 | Jul 11 – Jul 25 |
| Sweet Corn | — | — | May 21 – Jun 4 | — |
| Sweet Potatoes | — | May 28 – Jun 18 | — | — |
| Garlic | — | — | — | Sep 12 – Oct 17 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Carpenter 3n, WY weather station, 27 km away (elevation 5,436 ft (1,657 m)).
Frost dates near Grover
- Hereford May 14 · Sep 26
- Briggsdale May 12 · Sep 28
- New Raymer May 9 · Oct 4
- Galeton May 12 · Sep 28
- Nunn May 13 · Sep 27
- Gill May 2 · Oct 8
- Pierce May 13 · Sep 27
- Ault May 2 · Oct 8
- Stoneham May 9 · Oct 4
- Carr May 13 · Sep 27
Frequently asked questions
When is the last frost in Grover, CO?
The median last spring frost in Grover, CO is May 14. There is still about a 10% chance of frost after May 27, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Grover, CO?
The median first fall frost is September 26, with about a 10% chance of frost before September 12.
How long is the growing season in Grover, CO?
About 135 days between the median last spring frost and first fall frost.
What planting zone is Grover, CO?
Grover, CO is in USDA hardiness zone 5a.