There are many micro climates in Colorado. Therefore, areas that are relatively close to one another have different weather patterns, temperatures and hardiness zone ratings. However, the plant hardiness zone for Boulder is typically 5.
• The highest mountain areas 10,000+ are zone 3a-3b.
• Mountain and foothills area zones are 4a and 5a.
• Much of the populated front range is rated as zone 5a-5b.
• Warmest areas in Colorado are zones 5b-6b.
• “Hotspots” such as Denver, Ft. Collins and parts of the plains are zone 6b-7a.
Tempuratures (Fahrenheit)
-40 to- 35
-35 to -30
-30 to -25
-25 to -20
-20 to -15
-15 to -10
-10 to -5
-5 to 0
-0 to 5
USDA Hardiness Zones
3a
3b
4a
4b
5a
5b
6a
6b
7a
Hardiness zones for Colorado were revised in 2012 due to changes in climate temperatures.