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Denver, CO UV Index Today

Modelled for · GMT-6

What is the UV index in Denver right now?

2.7 Moderate

EPA suggests shade around midday, a hat and sunglasses.

Today's peak is 8.2 (Very High) at about 1pm local time.

When is UV strongest in Denver today?

UV in Denver peaks at 8.2 (Very High) around 1pm local time (GMT-6). It stays at 6 or above — the high band — for 3 hours, roughly 12pm to 3pm. UV is 3 or above for 6 hours.

Local time, midnight to midnight. Bar colour is the EPA UV band, never restyled.

Denver today, in numbers

Latitude
39.7°N — 57 of 121 from the north
Today's peak
8.2 (Very High) — 23 of 121 nationally
Peak arrives
1pm local (GMT-6)
At or above 6
3 hours, 12pm to 3pm
At or above 3
6 hours, 10am to 4pm

The window from 12pm to 3pm is the practical answer for Denver today. Nationally today the spread runs 11.4 in Hilo (20°N) to 1.3 in Fargo (47°N). Why latitude and the clock decide this →

A mile of missing air, and clock-accurate noon

The 105th meridian, the reference longitude for Mountain time, runs through Denver Union Station. Very few American cities sit that close to their own zone’s defining line, and the practical result is that solar noon here lands within about a minute of 12:00 standard time, or 1:00 p.m. once the clocks move. The daily maximum arrives when the clock says it should, which is not true of Phoenix or Salt Lake City, both of which run their peak nearly half an hour behind the clock.

Elevation does the rest. Denver’s benchmark is 5,280 feet, 1,609 meters. Applying WHO’s approximation of roughly 10 percent more UV per 1,000 meters puts the surface here on the order of 15 percent above sea level at the same latitude, before any local surface or cloud is accounted for.

Cloud arrives on a schedule worth knowing. From mid-July into September, moisture drawn north into Colorado builds afternoon thunderstorms over the Front Range that then drift onto the plains. Those clip the late afternoon more than midday, so a stormy week can still deliver its full readings before two o’clock. The stacking that catches people out comes earlier in the year: a clear March or April day with snow still lying at 5,280 feet, when altitude and reflectance combine under a sun angle already most of the way back toward summer.

Nearest metros we model

UV changes with latitude, not with a city boundary, so a neighbour a hundred miles north reads differently for a reason.

Boulder, CO 24 mi · 40.0°N peak 7.6 Fort Collins, CO 59 mi · 40.6°N peak 7.3 Colorado Springs, CO 64 mi · 38.8°N peak 8.1

What does Denver’s UV index mean today?

2.7 is Moderate. EPA suggests shade around midday, a hat and sunglasses. Today Denver also reaches Very High at its peak — a different band from the one it is in right now, which is why the hour matters as much as the day.

The scale is open-ended: 11 is where the named bands stop, not the maximum. All five bands, with the EPA guidance for each →

Modelled, not measured

The UV figures for Denver are computed by the Copernicus atmosphere model, not read off an instrument here — unlike the AQI on our air-quality pages, which comes from a regulatory monitor. Cloud is where a UV model is weakest. What that means in practice →

Questions about UV in Denver

What is the UV index in Denver today?

2.7 right now (Moderate), peaking at 8.2 around 1pm local time. UV stays at 6 or above for 3 hours, from about 12pm to 3pm. This is a modelled value, not a ground measurement.

When is UV strongest in Denver today?

Around 1pm local time (GMT-6), not at noon — solar noon drifts across a timezone and daylight saving moves it later on the clock.

Is this measured or modelled?

Modelled. The figures come from the Copernicus atmosphere model via Open-Meteo, unlike the AQI on our air-quality pages, which is read from an EPA regulatory monitor. Cloud cover is where a UV model is weakest.

Denver air qualityThe AQI, from a regulatory monitor rather than a model UV across the USWhere Denver sits against every metro we track

Updated