County Data
Jefferson County, Colorado
Self-reliance and preparedness data for Jefferson County
Relatively Moderate
Hazard Risk (16.7/100)
5b
USDA Zone
151
Frost-Free Days
Good
Solar (4.7 kWh/m²/day)
Natural Hazard Risks in Jefferson County
| Hazard | Risk Rating | Score |
|---|---|---|
| Hail | Relatively High | 37.1 |
| Wildfire | Relatively Moderate | 25.4 |
| Tornado | Relatively Moderate | 23.9 |
| Cold Wave | Relatively Moderate | 20.4 |
| Lightning | Relatively Moderate | 19.5 |
Source: FEMA National Risk Index. Scores 0–100, higher = more risk.
Wildfire Risk in Jefferson County
FEMA National Risk Index25.4/100 — Meaningful, seasonal. Ranked 109 of 562 US counties where wildfire is a leading hazard.
What that means for Jefferson County households
- ●Clear leaf litter from gutters and roof valleys before dry season
- ●Know your evacuation route and where local shelters open
- ●Stock N95 masks — smoke from distant fires is the more likely exposure
- ●Keep a two-week supply buffer for the periods when roads close
Full wildfire preparedness guide · See how Colorado compares
Climate Profile
Temperature & Growing Season
| January Avg | 28°F |
| July Avg | 72°F |
| USDA Zone | 5b |
| Frost-Free Days | 151 |
Water & Energy
| Annual Precipitation | 20.4″ |
| Solar Potential | 4.7 kWh/m²/day |
| Wind Speed | 2.5 m/s |
| Soil Type | Sandy Loam |
Local Species
45
Edible species
22
Medicinal species
61
Autonomy Score
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Frequently Asked Questions
- What are the biggest natural hazards in Jefferson County, Colorado?
- Jefferson County has an overall hazard rating of Relatively Moderate based on FEMA National Risk Index data. The top threats are Hail, Wildfire, Tornado. Each hazard is scored 0–100 by likelihood and expected impact.
- What is the growing season in Jefferson County?
- Jefferson County is in USDA Hardiness Zone 5b with approximately 151 frost-free days per year. This determines which crops, fruit trees, and perennials can survive your winters and how long your outdoor growing season lasts.
- Is Jefferson County good for solar power?
- Jefferson County has a good solar rating. Solar potential is based on average daily irradiance (kWh/m²/day), which determines how much energy rooftop or ground-mounted panels can produce year-round.
- How many edible plants grow in Jefferson County?
- Our database identifies 45 edible plant species in Jefferson County based on regional flora data, USDA hardiness zone, and iNaturalist observations. The full field guide includes identification notes, preparation methods, and seasonal availability.
- What is the autonomy score for Jefferson County?
- Jefferson County has an autonomy score of 61. This composite score measures local self-reliance potential across water access, food production capacity, energy resources, and supply chain resilience. Higher scores indicate greater potential for self-sufficiency.
Other Counties in Colorado
El Paso
Zone 5b • 153 frost-free days
Denver
Zone 6a • 154 frost-free days
Arapahoe
Zone 6a • 158 frost-free days
Adams
Zone 6a • 158 frost-free days
Larimer
Zone 5b • 53 frost-free days
Boulder
Zone 5b • 150 frost-free days
Douglas
Zone 5b • 141 frost-free days
Weld
Zone 5a • 159 frost-free days
Pueblo
Mesa
Zone 6a • 121 frost-free days
Garfield
Zone 5b • 112 frost-free days
Broomfield
Zone 5b • 150 frost-free days