Deconstruct SunColorado Hardiness Zones
Colorado covers USDA plant hardiness zones 4a to 7a on the 2023 map, so its coldest areas average −30 to −25 °F on the coldest winter night. Find your zone by ZIP code, or pick a city below for its zone, sunrise and daylight by month.
Colorado hardiness zone map
This is not the official USDA Plant Hardiness Zone Map. Zones are derived from the official 2023 dataset, resampled to about 2 km. Dots mark cities with their own page.
Source: USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture, planthardiness.ars.usda.gov. Underlying data © PRISM Group, Oregon State University, prism.oregonstate.edu, accessed 2026-08-30.
Zones and daylight by city
| City | Zone | Coldest night | Longest day | Shortest day |
|---|---|---|---|---|
| Denver | 6a | −10 to −5 °F | 14h 59m | 9h 21m |
| Colorado Springs | 6a | −10 to −5 °F | 14h 54m | 9h 27m |
| Aurora | 6a | −10 to −5 °F | 14h 59m | 9h 21m |
| Fort Collins | 5b | −15 to −10 °F | 15h 05m | 9h 16m |
| Lakewood | 6a | −10 to −5 °F | 14h 59m | 9h 22m |
| Thornton | 6a | −10 to −5 °F | 15h 00m | 9h 20m |
| Arvada | 6a | −10 to −5 °F | 15h 00m | 9h 21m |
| Westminster | 6a | −10 to −5 °F | 15h 00m | 9h 20m |
| Pueblo | 6a | −10 to −5 °F | 14h 50m | 9h 30m |
| Boulder | 6a | −10 to −5 °F | 15h 01m | 9h 20m |
| Greeley | 5b | −15 to −10 °F | 15h 04m | 9h 17m |
| Grand Junction | 7a | 0 to 5 °F | 14h 55m | 9h 25m |
| Durango | 6b | −5 to 0 °F | 14h 44m | 9h 36m |
Gardening in Colorado?
Your zone says what survives winter. Deconstruct Sun measures how many hours of direct sun your exact spot gets, so you can pick plants that thrive. Free on iPhone.
Questions
What hardiness zones are in Colorado?
Colorado spans USDA zones 4a to 7a on the 2023 map. Among its larger cities, Fort Collins is coldest (zone 5b) and Grand Junction is warmest (zone 7a).
How do I find my exact zone in Colorado?
Enter your ZIP code in the hardiness zone lookup on this site. It reads the 2023 USDA data for that ZIP and warns you if you are near a zone boundary.
How much sun do gardens in Colorado get?
In Denver, an open spot gets up to 15.0 hours of daylight in June but only 9.3 in December. Trees and buildings cut that down, especially in winter. The Deconstruct Sun app measures the real direct-sun hours for one exact spot.