UV index in Hamilton today
Inland Hamilton (CO) is 40.4° south. Without sea haze, January UV commonly runs 8–10 (very high), and a cool morning is no reason to skip sunscreen. This is cool-temperate America: summer UV still climbs into the very high band, and spring arrives before the weather feels hot.
Live reading · data by Open-Meteo · reference monitoring by ARPANSA
Today and tomorrow in Hamilton
Peak UV, temperature and conditions for Hamilton. Tomorrow’s peak is the number to plan around if you’re heading out in the middle of the day.
Weather conditions right now
Cloud and rain cut heat more than they cut UV. A partly cloudy day in Hamilton can still sit at protection levels. Why you burn on cloudy days.
When Hamilton needs sun protection
Sun protection is needed in Hamilton typically from May through September, and any clear spring or fall day UV reaches 3. Inland heat or a cool change does not change the UV index; go by the number, not how the day feels.
The threshold, per SunSmart and ARPANSA: whenever UV reaches 3 or above, Slip on covering clothing, Slop on SPF 50+ sunscreen, Slap on a hat, Seek shade and Slide on sunglasses. Read the full sun safety guide.
The UV scale at a glance
- 0–2Low
- 3–5Moderate
- 6–7High
- 8–10Very high
- 11+Extreme
Frequently asked questions
- When does Hamilton need sun protection?
- Whenever the UV index is 3 or above. In Hamilton that is typically from May through September, and any clear spring or fall day UV reaches 3. The EPA Sun Safety action steps apply at the same threshold used worldwide.
- Does Hamilton need sun protection in winter?
- Not every day. Midwinter middays in Hamilton often sit below UV 3, but clear late-winter and early-spring days cross the threshold before summer fully arrives. Check the live index.
- Can you burn on a cool day in Hamilton?
- Yes. UV is not heat. A cool, windy or lightly cloudy day in Hamilton can still sit at UV 3 or above, especially from spring through autumn. Temperature on this page is for context only; the UV number is what decides protection.