Frost dates for Allenspark 3nw, CO
At Allenspark 3nw, the median last spring frost (32°F) is Jun 14 and the median first fall frost is Sep 12, for a typical growing season of 92 days. For a 90% chance that the last frost has passed, wait until Jun 28. Nearby ZIP codes are in USDA hardiness zone 5b.
- Jun 14Last spring frost (median)50% chance of 32°F after this date
- Jun 28Safer planting date10% chance of 32°F after this date
- Sep 12First fall frost (median)50% chance of 32°F by this date
- 92 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 32°F | May 24 | Jun 14 | Jun 28 |
| 28°F | May 7 | May 27 | Jun 15 |
| 24°F | Apr 27 | May 9 | May 29 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 32°F | Aug 25 | Sep 12 | Sep 25 |
| 28°F | Sep 11 | Sep 25 | Oct 8 |
| 24°F | Sep 18 | Oct 5 | Oct 20 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 34 days | 58 days | 83 days |
| 32°F | 69 days | 92 days | 112 days |
| 28°F | 98 days | 120 days | 143 days |
| 24°F | 122 days | 145 days | 167 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 80510 | 5b | -15 to -10°F | 8 km |
| 80540 | 5b | -15 to -10°F | 10 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00050185, at 40.2289, -105.5183, elevation 2591 m (8,500 ft).
- Data quality: Representative (10+ years), 11 years of freeze data.
- Average days per year at or below 32°F: 224.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Estes Park 3 SSE (13 km)
- Boulder 14 W (22 km)
- Grand Lake 1 NW (27 km)
- Grand Lake 6 SSW (30 km)
- Boulder (34 km)
- Waterdale (34 km)
- Gross Rsvr (36 km)
- Longmont 2 ESE (38 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.