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Detroit, MI UV Index Today

Modelled for · GMT-4

What is the UV index in Detroit right now?

0.6 Low

EPA describes low UV as needing no protection for most people.

Today's peak is 5.7 (High) at about 1pm local time.

When is UV strongest in Detroit today?

UV in Detroit peaks at 5.7 (High) around 1pm local time (GMT-4). It does not reach the high band at any hour today. UV is 3 or above for 6 hours.

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

Detroit today, in numbers

Latitude
42.3°N — 30 of 121 from the north
Today's peak
5.7 (High) — 92 of 121 nationally
Peak arrives
1pm local (GMT-4)
At or above 6
not today
At or above 3
6 hours, 11am to 5pm

Detroit never reaches the high band today; the midday hours still warrant a hat. 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 →

Winter cloud that arrives already made

Detroit sits at 42.3 degrees north, within a few miles of Boston’s latitude, on ground about 600 feet above sea level. That elevation does nothing measurable to ultraviolet. What separates this place from other cities on the same parallel is where its winter cloud is manufactured.

The prevailing flow is westerly. Air arriving on it has already crossed Lake Michigan and the width of the Lower Peninsula; back the wind into the northwest and it has crossed Lake Huron as well. From late fall into early spring that air is colder than the water it passes over, takes up heat and moisture from below, and becomes a low stratus deck before it ever reaches the Detroit River. The city is at the receiving end of that process rather than in the middle of it, which is why the deck can hold for days instead of moving off behind a front, and why it lies over exactly the weeks when the noon sun is lowest.

By late June the lakes are no longer much colder than the air above them, the mechanism weakens, and the noon sun reaches about 71 degrees. The water close in gives nothing back on the way up: the World Health Organization puts ultraviolet reflected off water at under 10 percent. An afternoon on the riverbank is not a larger dose than the same afternoon in a parking lot.

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.

Cleveland, OH 90 mi · 41.5°N peak 5.5 Columbus, OH 164 mi · 40.0°N peak 6.3 Pittsburgh, PA 205 mi · 40.4°N peak 6

What does Detroit’s UV index mean today?

0.6 is Low. EPA describes low UV as needing no protection for most people. Today Detroit also reaches 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 Detroit 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 Detroit

What is the UV index in Detroit today?

0.6 right now (Low), peaking at 5.7 around 1pm local time. It does not reach the high band today. This is a modelled value, not a ground measurement.

When is UV strongest in Detroit today?

Around 1pm local time (GMT-4), 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.

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

Updated