UV Index in Idaho (ID)
Idaho has an average annual UV index of 4.8, classified as Moderate — 0.2 points below the national average of 5. UV levels peak in July with an average of 10, reaching Very High levels, and drop to 1.2 in December. During peak months, unprotected fair skin can burn in as little as 10 minutes. SPF 50+ sunscreen, protective clothing, and shade are strongly recommended. Idaho has 6 months per year with High or above UV levels. UV ranges from 4.4 in Coeur d'Alene to 6.3 in Sun Valley.
Monthly UV Index by City in Idaho
The heatmap below shows the monthly average UV index for 5 cities in Idaho. Colors range from green (low UV, 0-2) through yellow (moderate, 3-5), orange (high, 6-7), red (very high, 8-10), to purple (extreme, 11+). Hover over any cell to see the exact value.
| City | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Avg | Peak |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sun Valley | 2 | 3 | 5 | 7 | 9 | 11 | 11 | 10 | 8 | 5 | 3 | 2 | 6.3 | June |
| Idaho Falls | 2 | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 7 | 4 | 2 | 1 | 5.5 | June |
| Pocatello | 2 | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 7 | 4 | 2 | 1 | 5.5 | June |
| Boise | 1 | 3 | 4 | 6 | 8 | 10 | 10 | 9 | 7 | 4 | 2 | 1 | 5.4 | June |
| Coeur d'Alene | 1 | 2 | 3 | 5 | 7 | 8 | 9 | 8 | 5 | 3 | 1 | 1 | 4.4 | July |
Sun Protection Recommendations for Idaho
Based on the peak UV index of 10 (Very High) during July, here are the recommended sun safety measures for Idaho residents and visitors:
Very High UV — Very high risk of harm. Take extra precautions — unprotected skin can burn quickly.
- Apply SPF 50+ sunscreen generously, reapply every 90 minutes
- Wear UPF-rated clothing, wide-brimmed hat, and wraparound sunglasses
- Seek shade whenever possible
- Avoid outdoor activities between 10 AM and 4 PM if possible
- Be aware that sand, water, and concrete reflect UV and increase exposure
Recommended sunscreen: SPF 50+
Estimated Sunburn Times in Idaho (July Peak)
Approximate time to first sunburn at peak UV (10) without sunscreen, by skin type:
| Skin Type | Description | Time to Burn | Vitamin D Time |
|---|---|---|---|
| Type I | Very Fair | 7 min (high risk) | ~3 min |
| Type II | Fair | 10 min (high risk) | ~3 min |
| Type III | Medium | 20 min | ~5 min |
| Type IV | Olive | 30 min | ~8 min |
| Type V | Brown | 40 min | ~10 min |
| Type VI | Dark Brown/Black | 50 min | ~13 min |
In Idaho, sufficient vitamin D can be produced with just 5-10 minutes of midday sun exposure on arms and face during summer months.
Seasonal UV Patterns in Idaho
Idaho's UV index follows a seasonal pattern, with the lowest levels in December (UV 1.2) and the highest in July (UV 10). The seasonal swing of 8.8 UV points means sun protection needs change significantly throughout the year. Here are the state-average UV levels by month:
Summer months in Idaho consistently reach Very High or Extreme UV levels. Outdoor workers, athletes, and beachgoers should take extra precautions from May through September.
How Idaho Compares to Other States
Below is a comparison of Idaho with five states that have similar average UV index levels. Understanding how your state compares helps put your sun exposure risk in context.
| State | Avg UV | Level | Cities |
|---|---|---|---|
| Idaho (ID) | 4.8 | Moderate | 5 |
| District of Columbia (DC) | 4.8 | Moderate | 5 |
| Kentucky (KY) | 4.8 | Moderate | 5 |
| Maryland (MD) | 4.7 | Moderate | 6 |
| Missouri (MO) | 4.9 | Moderate | 5 |
| Virginia (VA) | 4.9 | Moderate | 6 |
UV Index in Neighboring States
Compare UV levels with states near Idaho:
Skin Cancer Risk Factors in Idaho
UV radiation is the primary environmental risk factor for skin cancer. While the UV index in Idaho is only one factor, understanding cumulative exposure is important. Key risk factors include:
- Cumulative UV exposure — total lifetime sun exposure, especially sunburns before age 18
- Skin type — fair skin (Types I-II) has significantly higher risk
- Geographic location — Idaho's moderate UV levels carry standard risk
- Altitude — higher elevations increase UV exposure significantly
- Outdoor occupation/hobbies — agricultural workers, construction workers, golfers, runners, and beach visitors accumulate more exposure
- Tanning bed use — artificial UV exposure dramatically increases risk
The American Academy of Dermatology recommends annual skin checks for everyone, with more frequent screenings for those with multiple risk factors. Early detection dramatically improves outcomes for all types of skin cancer.
Check UV for Your City
Use our UV index lookup tool to find your specific city in Idaho, or browse all 50 states ranked by UV index to compare UV levels across the country. For today's live UV forecast, check the EPA UV Index API with your zip code.