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Milwaukee, WI UV Index Today

Modelled for · GMT-5

What is the UV index in Milwaukee right now?

0.5 Low

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

Today's peak is 5.5 (High) at about 12pm local time.

When is UV strongest in Milwaukee today?

UV in Milwaukee peaks at 5.5 (High) around 12pm local time (GMT-5). It does not reach the high band at any hour today. UV is 3 or above for 5 hours.

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

Milwaukee today, in numbers

Latitude
43.0°N — 23 of 121 from the north
Today's peak
5.5 (High) — 97 of 121 nationally
Peak arrives
12pm local (GMT-5)
At or above 6
not today
At or above 3
5 hours, 10am to 3pm

Milwaukee 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 →

A Cold Lake Manufacturing Its Own Cloud

Milwaukee and Madison sit three hundredths of a degree apart in latitude, 43.04°N against 43.07°N. The sun does the identical thing over both cities on every day of the year. What separates their records is Lake Michigan.

Spring is when the lake asserts itself hardest. A published climatology of lake effect at Milwaukee puts its highest frequency in May, when the contrast between land and water temperature is greatest. The lake is still in the upper 30s and low 40s then, and warm, humid air moving north across that surface condenses into fog and low stratus. An easterly lake breeze arriving on a warm afternoon can drop shoreline temperatures ten to twenty degrees within minutes. For ultraviolet, the consequence is that the lakefront can sit under gray while five miles west the sky is clear, and the boundary between the two can cross neighborhoods inside an hour.

By midsummer the mechanism changes character rather than stopping. The lake breeze that forms on its own, with no larger weather pattern behind it, is most frequent in August, and it arrives on afternoons when the sun is already near its annual high. Through much of the warm season, the cloud governing Milwaukee’s index is manufactured a few miles offshore rather than delivered by a front.

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.

Madison, WI 75 mi · 43.1°N peak 4.5 Chicago, IL 81 mi · 41.9°N peak 6 Indianapolis, IN 243 mi · 39.8°N peak 6.7

What does Milwaukee’s UV index mean today?

0.5 is Low. EPA describes low UV as needing no protection for most people. Today Milwaukee 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 Milwaukee 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 Milwaukee

What is the UV index in Milwaukee today?

0.5 right now (Low), peaking at 5.5 around 12pm local time. It does not reach the high band today. This is a modelled value, not a ground measurement.

When is UV strongest in Milwaukee today?

Around 12pm local time (GMT-5), 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.

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

Updated