Allenspark, CO frost dates
Last spring frostJun 14median date
First fall frostSep 12median date
Growing season90 daysfrost-free
Hardiness zone5bZone 5b
How Allenspark compares
- In 8 years out of 10, the last spring frost in Allenspark falls between May 24 and June 28, a 35-day window. The first fall frost falls between August 25 and September 25.
- The median last frost is 34 days later than the Colorado median of May 11.
- Its 90-day growing season is longer than 9% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 44 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 225 nights a year at or below 32°F.
- Compared with Boulder, CO, 28 km away, the last frost here is 39 days later than there and the growing season is 62 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 24 |
| 50% (median) | June 14 |
| 10% (safe for tender plants) | June 28 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 25 |
| 50% (median) | September 12 |
| 90% (late) | September 25 |
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 Allenspark, CO
Allenspark, CO frost dates — last frost Jun 14, first frost Sep 12, zone 5b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 22 to Apr 5Transplant outside: May 17 to May 31
Start indoors: Apr 5 to Apr 19Transplant outside: Jun 28 to Jul 12
Start indoors: Apr 5 to Apr 19Transplant outside: Jun 28 to Jul 12
Start indoors: Apr 19 to May 3Transplant outside: Jun 21 to Jul 5
Start indoors: Apr 19 to May 3Transplant outside: May 24 to Jun 7Sow outdoors: May 17 to Jun 21Plant for fall: Jul 18 to Aug 15
Start indoors: Apr 19 to May 3Transplant outside: May 17 to May 31Sow outdoors: May 17 to May 31Plant for fall: Jul 4 to Jul 25
Start indoors: Apr 19 to May 3Transplant outside: May 31 to Jun 14
Start indoors: Apr 19 to May 3Transplant outside: May 24 to Jun 7
Start indoors: Apr 19 to May 3Transplant outside: May 31 to Jun 14
Start indoors: May 3 to May 17Transplant outside: Jul 5 to Jul 19Sow outdoors: Jul 5 to Jul 19
Start indoors: May 3 to May 17Transplant outside: Jun 21 to Jul 5
Sow outdoors: May 3 to May 24
Sow outdoors: May 3 to May 24Plant for fall: Jul 18 to Aug 8
Sow outdoors: May 10 to Jun 21Plant for fall: Aug 1 to Aug 22
Start indoors: May 17 to May 24Transplant outside: Jun 28 to Jul 5Sow outdoors: Jun 21 to Jul 5
Start indoors: May 17 to May 24Sow outdoors: Jun 21 to Jul 5
Start indoors: May 17 to May 24Sow outdoors: Jun 21 to Jul 5
Start indoors: May 17 to May 24Transplant outside: Jun 28 to Jul 12
Sow outdoors: May 24 to Jun 21
Sow outdoors: May 24 to Jun 21
Sow outdoors: May 24 to Jun 14
Sow outdoors: May 31 to Jun 28
Sow outdoors: May 31 to Jun 21Plant for fall: Jul 18 to Aug 8
Sow outdoors: Jun 21 to Jul 12
Sow outdoors: Jun 21 to Jul 5
Transplant outside: Jun 28 to Jul 19
Plant for fall: Aug 29 to Oct 3
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Allenspark, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 22 – Apr 5 | May 17 – May 31 | — | — |
| Peppers | Apr 5 – Apr 19 | Jun 28 – Jul 12 | — | — |
| Eggplant | Apr 5 – Apr 19 | Jun 28 – Jul 12 | — | — |
| Tomatoes | Apr 19 – May 3 | Jun 21 – Jul 5 | — | — |
| Lettuce | Apr 19 – May 3 | May 24 – Jun 7 | May 17 – Jun 21 | Jul 18 – Aug 15 |
| Kale | Apr 19 – May 3 | May 17 – May 31 | May 17 – May 31 | Jul 4 – Jul 25 |
| Broccoli | Apr 19 – May 3 | May 31 – Jun 14 | — | — |
| Cabbage | Apr 19 – May 3 | May 24 – Jun 7 | — | — |
| Cauliflower | Apr 19 – May 3 | May 31 – Jun 14 | — | — |
| Okra | May 3 – May 17 | Jul 5 – Jul 19 | Jul 5 – Jul 19 | — |
| Basil | May 3 – May 17 | Jun 21 – Jul 5 | — | — |
| Peas | — | — | May 3 – May 24 | — |
| Spinach | — | — | May 3 – May 24 | Jul 18 – Aug 8 |
| Radishes | — | — | May 10 – Jun 21 | Aug 1 – Aug 22 |
| Cucumbers | May 17 – May 24 | Jun 28 – Jul 5 | Jun 21 – Jul 5 | — |
| Zucchini & Summer Squash | May 17 – May 24 | — | Jun 21 – Jul 5 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 90 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 17 – May 24 | — | Jun 21 – Jul 5 | — |
| Melons & Watermelon Warning: Your frost-free season is about 90 days, which is tight for melons & watermelon (85+ days). Choose early varieties and use transplants or row covers. | May 17 – May 24 | Jun 28 – Jul 12 | — | — |
| Carrots | — | — | May 24 – Jun 21 | — |
| Beets | — | — | May 24 – Jun 21 | — |
| Potatoes | — | — | May 24 – Jun 14 | — |
| Swiss Chard | — | — | May 31 – Jun 28 | — |
| Cilantro | — | — | May 31 – Jun 21 | Jul 18 – Aug 8 |
| Green Beans | — | — | Jun 21 – Jul 12 | — |
| Sweet Corn Warning: Your frost-free season is about 90 days, which is tight for sweet corn (80+ days). Choose early varieties and use transplants or row covers. | — | — | Jun 21 – Jul 5 | — |
| Sweet Potatoes Warning: Your frost-free season is about 90 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 28 – Jul 19 | — | — |
| Garlic | — | — | — | Aug 29 – Oct 3 |
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 Allenspark 3nw, CO weather station, about 1 km away (elevation 8,501 ft (2,591 m)).
Frost dates near Allenspark
- Estes Park (Larimer) May 30 · Sep 17
- Jamestown Jun 21 · Sep 2
- Lyons Jun 14 · Sep 12
- Ward Jun 21 · Sep 2
- Hygiene May 7 · Oct 5
- Drake May 30 · Sep 17
- Glen Haven May 30 · Sep 17
- Boulder May 6 · Oct 5
- Nederland Jun 21 · Sep 2
- Grand Lake frost any month
Frequently asked questions
When is the last frost in Allenspark, CO?
The median last spring frost in Allenspark, CO is June 14. There is still about a 10% chance of frost after June 28, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Allenspark, CO?
The median first fall frost is September 12, with about a 10% chance of frost before August 25.
How long is the growing season in Allenspark, CO?
About 90 days between the median last spring frost and first fall frost.
What planting zone is Allenspark, CO?
Allenspark, CO is in USDA hardiness zone 5b.