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San Diego, CA UV Index Today

Modelled for · GMT-7

What is the UV index in San Diego right now?

5.6 High

EPA suggests shade between 10am and 4pm, plus a shirt and sunscreen.

Today's peak is 9 (Very High) at about 1pm local time.

When is UV strongest in San Diego today?

UV in San Diego peaks at 9 (Very High) around 1pm local time (GMT-7). It stays at 6 or above — the high band — for 4 hours, roughly 11am to 3pm. UV is 3 or above for 7 hours.

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

San Diego today, in numbers

Latitude
32.7°N — 105 of 121 from the north
Today's peak
9 (Very High) — 7 of 121 nationally
Peak arrives
1pm local (GMT-7)
At or above 6
4 hours, 11am to 3pm
At or above 3
7 hours, 10am to 5pm

The window from 11am to 3pm is the practical answer for San Diego 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 →

Cloud peaks in the same weeks the sun does

NOAA’s sunshine record for San Diego, which runs from 1965 to 1977, puts May at 56 percent of possible sunshine and June at 57, the two lowest months of the year, and December at 75, the highest. The cloudiest stretch of the calendar sits directly on top of the strongest sun, and the clearest sits on the weakest. Almost nowhere inland does the year run in that order.

The mechanism is the marine layer. Cold water offshore under a subsidence inversion builds a stratus deck overnight that is thickest around dawn, the pattern known here as May Gray and June Gloom. It burns back through the morning, and the inland neighborhoods come out from under it before the coast does, so two readings taken a few miles apart at eleven in the morning can be describing different days.

Timing decides how much that costs. Solar noon in San Diego falls close to 12:49 p.m. in daylight time, because the city lies almost three degrees east of the 120th meridian that sets Pacific time. Its peak therefore arrives earlier on the clock than Los Angeles’s or San Francisco’s, often inside the same couple of hours the deck is breaking up. A May morning that looked written off can still produce the day’s highest reading. Elevation adds nothing at the coast.

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.

Irvine, CA 77 mi · 33.7°N peak 8.8 Riverside, CA 86 mi · 34.0°N peak 9.4 Anaheim, CA 89 mi · 33.8°N peak 8.8

What does San Diego’s UV index mean today?

5.6 is High. EPA suggests shade between 10am and 4pm, plus a shirt and sunscreen. Today San Diego 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 San Diego 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 San Diego

What is the UV index in San Diego today?

5.6 right now (High), peaking at 9 around 1pm local time. UV stays at 6 or above for 4 hours, from about 11am to 3pm. This is a modelled value, not a ground measurement.

When is UV strongest in San Diego today?

Around 1pm local time (GMT-7), 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.

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

Updated