UV index in Phoenix in August
In August, the UV index in Phoenix typically peaks around 8.2 at midday — very high on the WHO scale — with individual days reaching 8.7 in recent years. Sun protection is needed around the middle of the day.
How fast would you burn?
Estimated time to sunburn in unprotected midday sun at UV 8.2:
| Skin type | Time to burn |
|---|---|
| I — Very fair | ~16 min |
| II — Fair | ~20 min |
| III — Medium | ~28 min |
| IV — Olive | ~37 min |
Estimates from typical minimal erythemal doses — see methodology. Darker types (V–VI) burn slower still. Reflection off water or sand shortens all of these.
What to do about it
- Treat midday sun as hostile: SPF 50, a real hat, UV-blocking sunglasses, and shade between 11am and 3pm.
- Fair skin (types I–II) can burn in 15–25 minutes at these levels — reapply sunscreen strictly every 2 hours.
- UPF-rated clothing outperforms sunscreen for long days out — consider a sun shirt for beach or boat days.
Planning a trip? Check the live UV index in Phoenix closer to your dates — day-to-day cloud cover moves the real number around this average.
Phoenix's UV year at a glance
| Month | Typical midday peak | Level |
|---|---|---|
| January | 4 | Moderate |
| February | 5.2 | Moderate |
| March | 6.5 | High |
| April | 7.8 | High |
| May | 8.3 | Very high |
| June | 8.6 | Very high |
| July | 8.7 | Very high |
| August | 8.2 | Very high |
| September | 7.3 | High |
| October | 5.9 | Moderate |
| November | 4.5 | Moderate |
| December | 3.8 | Moderate |
The strongest month is July (typical peak 8.7); the gentlest is December (typical peak 3.8).
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