Olathe, CO frost dates
Last spring frostMay 2median date
First fall frostOct 8median date
Growing season159 daysfrost-free
Hardiness zone6bZone 6b
How Olathe compares
- In 8 years out of 10, the last spring frost in Olathe falls between April 19 and May 17, a 28-day window. The first fall frost falls between September 26 and October 22.
- The median last frost is 9 days earlier than the Colorado median of May 11.
- Its 159-day growing season is longer than 76% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 10 days later than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b chart.
- The weather station records an average of 156 nights a year at or below 32°F.
- Compared with Grand Junction, CO, 70 km away, the last frost here is 9 days later than there and the growing season is 21 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 19 |
| 50% (median) | May 2 |
| 10% (safe for tender plants) | May 17 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 26 |
| 50% (median) | October 8 |
| 90% (late) | October 22 |
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 Olathe, CO
Olathe, CO frost dates — last frost May 2, first frost Oct 8, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Feb 7 to Feb 21Transplant outside: Apr 4 to Apr 18
Start indoors: Feb 21 to Mar 7Transplant outside: May 16 to May 30
Start indoors: Feb 21 to Mar 7Transplant outside: May 16 to May 30
Start indoors: Mar 7 to Mar 21Transplant outside: May 9 to May 23
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 11 to Apr 25Sow outdoors: Apr 4 to May 9Plant for fall: Aug 13 to Sep 10
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 4 to Apr 18Sow outdoors: Apr 4 to Apr 18Plant for fall: Jul 30 to Aug 20
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 18 to May 2Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 11 to Apr 25Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 7 to Mar 21Transplant outside: Apr 18 to May 2Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 21 to Apr 4Transplant outside: May 23 to Jun 6Sow outdoors: May 23 to Jun 6
Start indoors: Mar 21 to Apr 4Transplant outside: May 9 to May 23
Sow outdoors: Mar 21 to Apr 11Plant for fall: Jul 16 to Aug 6
Sow outdoors: Mar 21 to Apr 11Plant for fall: Aug 13 to Sep 3
Sow outdoors: Mar 28 to May 9Plant for fall: Aug 27 to Sep 17
Start indoors: Apr 4 to Apr 11Transplant outside: May 16 to May 23Sow outdoors: May 9 to May 23Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 4 to Apr 11Sow outdoors: May 9 to May 23Plant for fall: Jul 30 to Aug 13
Start indoors: Apr 4 to Apr 11Sow outdoors: May 9 to May 23
Start indoors: Apr 4 to Apr 11Transplant outside: May 16 to May 30
Sow outdoors: Apr 11 to May 9Plant for fall: Jul 16 to Jul 30
Sow outdoors: Apr 11 to May 9Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 11 to May 2
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 18 to May 9Plant for fall: Aug 13 to Sep 3
Sow outdoors: May 9 to May 30Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 9 to May 23
Transplant outside: May 16 to Jun 6
Plant for fall: Sep 24 to Oct 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Olathe, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 7 – Feb 21 | Apr 4 – Apr 18 | — | — |
| Peppers | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Eggplant | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Tomatoes | Mar 7 – Mar 21 | May 9 – May 23 | — | — |
| Lettuce | Mar 7 – Mar 21 | Apr 11 – Apr 25 | Apr 4 – May 9 | Aug 13 – Sep 10 |
| Kale | Mar 7 – Mar 21 | Apr 4 – Apr 18 | Apr 4 – Apr 18 | Jul 30 – Aug 20 |
| Broccoli | Mar 7 – Mar 21 | Apr 18 – May 2 | — | Jul 2 – Jul 23 |
| Cabbage | Mar 7 – Mar 21 | Apr 11 – Apr 25 | — | Jul 2 – Jul 23 |
| Cauliflower | Mar 7 – Mar 21 | Apr 18 – May 2 | — | Jul 2 – Jul 23 |
| Okra | Mar 21 – Apr 4 | May 23 – Jun 6 | May 23 – Jun 6 | — |
| Basil | Mar 21 – Apr 4 | May 9 – May 23 | — | — |
| Peas | — | — | Mar 21 – Apr 11 | Jul 16 – Aug 6 |
| Spinach | — | — | Mar 21 – Apr 11 | Aug 13 – Sep 3 |
| Radishes | — | — | Mar 28 – May 9 | Aug 27 – Sep 17 |
| Cucumbers | Apr 4 – Apr 11 | May 16 – May 23 | May 9 – May 23 | Jul 23 – Aug 6 |
| Zucchini & Summer Squash | Apr 4 – Apr 11 | — | May 9 – May 23 | Jul 30 – Aug 13 |
| Winter Squash & Pumpkins | Apr 4 – Apr 11 | — | May 9 – May 23 | — |
| Melons & Watermelon | Apr 4 – Apr 11 | May 16 – May 30 | — | — |
| Carrots | — | — | Apr 11 – May 9 | Jul 16 – Jul 30 |
| Beets | — | — | Apr 11 – May 9 | Jul 30 – Aug 13 |
| Potatoes | — | — | Apr 11 – May 2 | — |
| Swiss Chard | — | — | Apr 18 – May 16 | Jul 30 – Aug 13 |
| Cilantro | — | — | Apr 18 – May 9 | Aug 13 – Sep 3 |
| Green Beans | — | — | May 9 – May 30 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 9 – May 23 | — |
| Sweet Potatoes | — | May 16 – Jun 6 | — | — |
| Garlic | — | — | — | Sep 24 – Oct 29 |
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 Montrose Rgnl Ap, CO weather station, 13 km away (elevation 5,758 ft (1,755 m)).
Frost dates near Olathe
- Delta May 1 · Oct 7
- Montrose Apr 28 · Oct 14
- Cory May 1 · Oct 7
- Austin May 1 · Oct 7
- Lazear May 3 · Oct 12
- Eckert May 3 · Oct 9
- Hotchkiss May 3 · Oct 12
- Crawford May 23 · Oct 1
- Cedaredge May 3 · Oct 9
- Paonia May 3 · Oct 12
Frequently asked questions
When is the last frost in Olathe, CO?
The median last spring frost in Olathe, CO is May 2. There is still about a 10% chance of frost after May 17, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Olathe, CO?
The median first fall frost is October 8, with about a 10% chance of frost before September 26.
How long is the growing season in Olathe, CO?
About 159 days between the median last spring frost and first fall frost.
What planting zone is Olathe, CO?
Olathe, CO is in USDA hardiness zone 6b.