The best time of day to tan
The best time is the shoulder of the day, not the peak — the stretch where the UV index is above 2, so your skin responds, and below your own limit, so you are not on a countdown. For type II that limit is UV 4.2. The chart below is that window where you are, on the next forecast day with any sun in it.
Today in Columbus
UV 0 right now (low) · peak UV 8.6 at 14:00 · skin type II window 11:07–11:35 and 16:36–17:49
- 14:00 Peak UV hour
- 19 min Time to redness at peak, type II
- 11:07–11:35 First of 2 windows
- 11:20–17:13 Protection recommended (UV 3+, WHO)
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. Since a tan is built from repeated sub-threshold doses rather than one large one, the shoulder hours are not a compromise — they are the only part of the day long enough to do the job.
Your window by skin type
| Skin type | UV ceiling | On a UV 8 day | Time at UV 8 |
|---|---|---|---|
| Type I | UV 3.3 | Morning and late afternoon only | 17 min |
| Type II | UV 4.2 | Morning and late afternoon only | 21 min |
| Type III | UV 5 | Morning and late afternoon only | 25 min |
| Type IV | UV 6.7 | Morning and late afternoon only | 33 min |
| Type V | UV 8.3 | Continuous window | 42 min |
| Type VI | UV 10 | Continuous window | 50 min |
The three things that move the window
Cloud moves it least. A half-covered sky removes about 7% of the UV, which shifts the edge of the window by minutes, not hours. A fully overcast sky removes about 75% and usually closes the window from the other end — not enough UV to tan at all.
Altitude narrows it: 12% more UV per 1,000 m, so a mountain window opens later and closes earlier than a coastal one at the same latitude.
What is under you narrows it most and is the one people forget. Dry sand adds about 15%, water alongside you about 20%, fresh snow up to 80%. A beach window is meaningfully shorter than a garden window on the same day.
Where the sun is strongest right now
- Cairns — UV 8.4Very high · Australia · peak at 12:00 tomorrow · type II window 08:42–09:42
- Darwin — UV 6.7High · Australia · peak at 13:30 tomorrow · type II window 09:06–10:12
- Brighton — UV 6.5High · United Kingdom · peak at 13:00 · type II window 10:00–10:22
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 is at its highest for the two hours either side of solar noon and drops steeply outside them. At the shoulders you get a UV level that still produces melanin while leaving enough time before the erythemal threshold to actually use it.
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 crosses into a burn in about 21 min; at UV 4 the same skin has 42 min. Both sessions can deliver the same amount of energy — only one of them is long enough to be a session at all.
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 2 well past 17:00, while in March it drops below 2 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?
Yes, and it is the main reason a single answer does not exist. The upper limit is the UV level that leaves 40 minutes before redness: UV 3.3 for type I, UV 4.2 for type II, UV 5 for type III, UV 6.7 for type IV, UV 8.3 for type V, UV 10 for type VI. On a UV 8 day, type I and II have to stay on the shoulders while type VI has a continuous window.
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.