Calhan, CO frost dates
Last spring frostMay 6median date
First fall frostOct 3median date
Growing season150 daysfrost-free
Hardiness zone5bZone 5b
How Calhan compares
- In 8 years out of 10, the last spring frost in Calhan falls between April 21 and May 28, a 37-day window. The first fall frost falls between September 21 and October 16.
- The median last frost is 5 days earlier than the Colorado median of May 11.
- Its 150-day growing season is longer than 55% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 5 days later than the zone 5b median of May 1. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5b chart.
- The weather station records an average of 160 nights a year at or below 32°F.
- Compared with Colorado Springs, CO, 38 km away, the last frost here is 3 days later than there and the growing season is 8 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 21 |
| 50% (median) | May 6 |
| 10% (safe for tender plants) | May 28 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 21 |
| 50% (median) | October 3 |
| 90% (late) | October 16 |
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 Calhan, CO
Calhan, CO frost dates — last frost May 6, first frost Oct 3, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Feb 11 to Feb 25Transplant outside: Apr 8 to Apr 22
Start indoors: Feb 25 to Mar 11Transplant outside: May 20 to Jun 3
Start indoors: Feb 25 to Mar 11Transplant outside: May 20 to Jun 3
Start indoors: Mar 11 to Mar 25Transplant outside: May 13 to May 27
Start indoors: Mar 11 to Mar 25Transplant outside: Apr 15 to Apr 29Sow outdoors: Apr 8 to May 13Plant for fall: Aug 8 to Sep 5
Start indoors: Mar 11 to Mar 25Transplant outside: Apr 8 to Apr 22Sow outdoors: Apr 8 to Apr 22Plant for fall: Jul 25 to Aug 15
Start indoors: Mar 11 to Mar 25Transplant outside: Apr 22 to May 6Plant for fall: Jun 27 to Jul 18
Start indoors: Mar 11 to Mar 25Transplant outside: Apr 15 to Apr 29Plant for fall: Jun 27 to Jul 18
Start indoors: Mar 11 to Mar 25Transplant outside: Apr 22 to May 6Plant for fall: Jun 27 to Jul 18
Start indoors: Mar 25 to Apr 8Transplant outside: May 27 to Jun 10Sow outdoors: May 27 to Jun 10
Start indoors: Mar 25 to Apr 8Transplant outside: May 13 to May 27
Sow outdoors: Mar 25 to Apr 15Plant for fall: Jul 11 to Aug 1
Sow outdoors: Mar 25 to Apr 15Plant for fall: Aug 8 to Aug 29
Sow outdoors: Apr 1 to May 13Plant for fall: Aug 22 to Sep 12
Start indoors: Apr 8 to Apr 15Transplant outside: May 20 to May 27Sow outdoors: May 13 to May 27Plant for fall: Jul 18 to Aug 1
Start indoors: Apr 8 to Apr 15Sow outdoors: May 13 to May 27Plant for fall: Jul 25 to Aug 8
Start indoors: Apr 8 to Apr 15Sow outdoors: May 13 to May 27
Start indoors: Apr 8 to Apr 15Transplant outside: May 20 to Jun 3
Sow outdoors: Apr 15 to May 13Plant for fall: Jul 11 to Jul 25
Sow outdoors: Apr 15 to May 13Plant for fall: Jul 25 to Aug 8
Sow outdoors: Apr 15 to May 6
Sow outdoors: Apr 22 to May 20Plant for fall: Jul 25 to Aug 8
Sow outdoors: Apr 22 to May 13Plant for fall: Aug 8 to Aug 29
Sow outdoors: May 13 to Jun 3Plant for fall: Jul 18 to Aug 1
Sow outdoors: May 13 to May 27
Transplant outside: May 20 to Jun 10
Plant for fall: Sep 19 to Oct 24
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Calhan, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 11 – Feb 25 | Apr 8 – Apr 22 | — | — |
| Peppers | Feb 25 – Mar 11 | May 20 – Jun 3 | — | — |
| Eggplant | Feb 25 – Mar 11 | May 20 – Jun 3 | — | — |
| Tomatoes | Mar 11 – Mar 25 | May 13 – May 27 | — | — |
| Lettuce | Mar 11 – Mar 25 | Apr 15 – Apr 29 | Apr 8 – May 13 | Aug 8 – Sep 5 |
| Kale | Mar 11 – Mar 25 | Apr 8 – Apr 22 | Apr 8 – Apr 22 | Jul 25 – Aug 15 |
| Broccoli | Mar 11 – Mar 25 | Apr 22 – May 6 | — | Jun 27 – Jul 18 |
| Cabbage | Mar 11 – Mar 25 | Apr 15 – Apr 29 | — | Jun 27 – Jul 18 |
| Cauliflower | Mar 11 – Mar 25 | Apr 22 – May 6 | — | Jun 27 – Jul 18 |
| Okra | Mar 25 – Apr 8 | May 27 – Jun 10 | May 27 – Jun 10 | — |
| Basil | Mar 25 – Apr 8 | May 13 – May 27 | — | — |
| Peas | — | — | Mar 25 – Apr 15 | Jul 11 – Aug 1 |
| Spinach | — | — | Mar 25 – Apr 15 | Aug 8 – Aug 29 |
| Radishes | — | — | Apr 1 – May 13 | Aug 22 – Sep 12 |
| Cucumbers | Apr 8 – Apr 15 | May 20 – May 27 | May 13 – May 27 | Jul 18 – Aug 1 |
| Zucchini & Summer Squash | Apr 8 – Apr 15 | — | May 13 – May 27 | Jul 25 – Aug 8 |
| Winter Squash & Pumpkins | Apr 8 – Apr 15 | — | May 13 – May 27 | — |
| Melons & Watermelon | Apr 8 – Apr 15 | May 20 – Jun 3 | — | — |
| Carrots | — | — | Apr 15 – May 13 | Jul 11 – Jul 25 |
| Beets | — | — | Apr 15 – May 13 | Jul 25 – Aug 8 |
| Potatoes | — | — | Apr 15 – May 6 | — |
| Swiss Chard | — | — | Apr 22 – May 20 | Jul 25 – Aug 8 |
| Cilantro | — | — | Apr 22 – May 13 | Aug 8 – Aug 29 |
| Green Beans | — | — | May 13 – Jun 3 | Jul 18 – Aug 1 |
| Sweet Corn | — | — | May 13 – May 27 | — |
| Sweet Potatoes | — | May 20 – Jun 10 | — | — |
| Garlic | — | — | — | Sep 19 – Oct 24 |
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 Ellicott 7s, CO weather station, 25 km away (elevation 5,738 ft (1,749 m)).
Frost dates near Calhan
- Peyton May 9 · Oct 6
- Ramah May 9 · Oct 4
- Elbert May 29 · Sep 21
- Yoder May 9 · Oct 4
- Rush May 9 · Oct 4
- Simla May 12 · Oct 2
- Colorado Springs May 3 · Oct 8
- Kiowa May 16 · Oct 2
- Fountain May 3 · Oct 8
- Matheson May 12 · Oct 2
Frequently asked questions
When is the last frost in Calhan, CO?
The median last spring frost in Calhan, CO is May 6. There is still about a 10% chance of frost after May 28, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Calhan, CO?
The median first fall frost is October 3, with about a 10% chance of frost before September 21.
How long is the growing season in Calhan, CO?
About 150 days between the median last spring frost and first fall frost.
What planting zone is Calhan, CO?
Calhan, CO is in USDA hardiness zone 5b.