The best time of day to tan
The shoulders of the day, not the peak. UV tracks the sun's height, so the hours either side of solar noon carry far less of it per minute — the same colour costs a slower dose. That is less harm, not no harm: no hour makes a tan risk-free, and the WHO recommends protection from UV 3 upward. The chart below is the curve where you are, on the next forecast day with any sun in it.
A weather-based estimate, not a personal safety limit. Skin damage builds up before any redness shows, and the times below assume unprotected skin under a clear sky.
Tomorrow in Columbus
peak UV 6.6 at 13:00 · type II has about 25 min of unprotected sun before the first redness at the peak · protection recommended (WHO) 10:35–16:08
- 13:00 Peak UV hour tomorrow
- 25 min Est. first redness at peak, type II
- 10:35–16:08 Protection recommended (UV 3+, WHO)
| Skin type | At peak UV 6.6 |
|---|---|
| I | 20 min |
| II | 25 min |
| III | 30 min |
| IV | 40 min |
| V | 51 min |
| VI | 61 min |
Why the peak is the wrong target
UV tracks the sine of the sun's elevation, which means it is not a plateau across the middle of the day — it is a curve with a sharp top. Around solar noon it barely moves for two hours, then falls quickly. That flat top is precisely the part of the day where every skin type has its shortest clock, and where the difference between a tan and a burn is a few minutes of inattention.
The arithmetic is unforgiving in one direction only. Doubling the UV halves your time; halving the UV doubles it. That is the whole case for the shoulders — they buy minutes. What they do not buy is immunity: the dose still lands, and the pigment it produces is still the skin repairing damage.
What a UV 8 day costs, by skin type
| Skin type | MED | At the peak, UV 8 | On the shoulder, UV 5 |
|---|---|---|---|
| Type I | 200 J/m² | 17 min | 27 min |
| Type II | 250 J/m² | 21 min | 33 min |
| Type III | 300 J/m² | 25 min | 40 min |
| Type IV | 400 J/m² | 33 min | 53 min |
| Type V | 500 J/m² | 42 min | 67 min |
| Type VI | 600 J/m² | 50 min | 80 min |
The three things that move the window
Cloud moves it least. A half-covered sky removes about 7% of the UV, which shifts your clock by minutes, not hours. A fully overcast sky removes about 75% — which is also below the level where skin produces any colour at all.
Altitude shortens it: 12% more UV per 1,000 m, so the same hour in the mountains costs more than at the coast on the same latitude.
What is under you shortens it most and is the one people forget. Dry sand adds about 15%, water alongside you about 20%, fresh snow up to 80%. An hour on the beach is meaningfully more UV than an hour in the garden on the same day.
Where the sun is strongest right now
- Darwin — UV 12.2Extreme · Australia · peak at 12:30 · type II: 14 min to first redness at the peak
- Cairns — UV 11.2Extreme · Australia · peak at 13:00 · type II: 15 min to first redness at the peak
- Brisbane — UV 8.4Very high · Australia · peak at 12:00 · type II: 20 min to first redness at the peak
Questions people ask about this
What is the best time of day to tan?
The two shoulders of the solar day — roughly 09:00 to 11:00 and 15:00 to 17:00 in summer at mid-latitudes. UV follows the sun angle, so it peaks for the two hours either side of solar noon and drops steeply outside them. The shoulders carry less UV per minute, which slows the dose; it does not make the exposure risk-free, and the WHO recommends protection from UV 3 whatever the hour.
Why not tan at midday when the sun is strongest?
Because the dose is UV × time, and at midday the time runs out first. At UV 8, type II reaches the first redness in about 21 min; at UV 4 the same skin has 42 min. Both can deliver the same amount of energy — the midday version is simply far easier to overshoot without noticing.
Is it true that you cannot tan after 4pm?
It depends on the date and the latitude, not the clock. Tanning needs roughly UV 2, and in a British June the index is still above that well past 17:00, while in March it drops below it by mid-afternoon. The chart on this page shows where the curve actually crosses that line for your location.
Does the best time change with skin type?
The shape of the day is the same for everyone — UV peaks around solar noon — but the clock is not. At UV 8, the estimated time to first redness runs from 17 min for type I to 50 min for type VI. That is a difference in speed, not in kind: no skin type has a level at which sun exposure is risk-free.
Does time of year matter more than time of day?
They are the same mechanism. Both the season and the hour change one thing — the angle of the sun above the horizon — and the UV index follows that angle. This is why the peak UV of a June morning at 09:00 can match the peak UV of a whole day in March.