Terms
UV Hour estimates how long unprotected skin takes to redden, from a public weather forecast. It is not medical advice, it cannot know your particular skin, and it must never be used to justify staying out longer. Using the site or the app means accepting that.
What this is not
Every figure here is an estimate built on a weather forecast and a published table of average doses. It assumes a healthy adult, unprotected skin and a clear reading of the sky. It knows nothing about how you applied sunscreen, what medication you take, what your skin has already absorbed today, or how you personally react to the sun.
Skin damage accumulates below the point where anything is visible, so "no redness" is not "no harm". Do not use these numbers to extend time in the sun, and do not rely on them at all for children, or if you have a history of skin cancer, a skin condition, or take photosensitising medication. If you have any doubt, ask a doctor rather than this website.
Weather forecasts are wrong sometimes, and so is arithmetic applied to a wrong forecast. We give no warranty that any figure is accurate, and we accept no liability for what you decide to do with it. Judging your own exposure remains yours.
Using the site
The calculator is free, needs no account, and stays that way. You may read it, link to it and quote its figures. Please do not scrape it in bulk — the forecast underneath comes from a public service with its own rate limits, and hammering us means hammering them.
The iPhone app, free and Pro
The app is free to download. Today's window, your skin profile and the session timer are included at no cost. UV Hour Pro unlocks window alerts, the full seven-day forecast, multiple profiles and your exposure history.
Pro is sold three ways through the App Store:
- a weekly subscription, renewing automatically every week;
- a yearly subscription, renewing automatically every year;
- a one-time purchase, which never renews.
Prices are set in your local currency and shown in the App Store and on the purchase screen before you confirm anything. There is currently no free trial: a subscription is charged from the start of the first period.
A subscription renews automatically unless you cancel it at least 24 hours before the end of the current period, and your account is charged for renewal within the 24 hours before it ends. You can cancel at any time from your Apple ID subscription settings on your device — not from inside the app, which cannot cancel on your behalf. Cancelling stops the next renewal; the period you already paid for runs to its end.
Apple takes the payment and issues any refund. We hold no payment details and cannot refund a purchase ourselves — refund requests go to Apple. Restoring a previous purchase on a new device is done from the app's paywall screen.
Weather data
Weather data from MET Norway (CC BY 4.0). It is used under the Creative Commons Attribution 4.0 licence and remains the property of the Norwegian Meteorological Institute, which is not affiliated with UV Hour and does not endorse it. The arithmetic applied to that data is ours and is published in full on the method page.
Intellectual property
The content of this site — text, visuals and logo — belongs to AGENCE DEBORD EURL unless stated otherwise. Reproduction without permission is not allowed. The weather data underneath is a separate matter and stays under its own licence, described above.
Who runs this
- Publisher: AGENCE DEBORD EURL, Entreprise unipersonnelle à responsabilité limitée, 9 rue des Colonnes, 75002 Paris, France.
- Director of publication: Aurélien Debord.
- Host: Cloudflare, Inc., 101 Townsend St, San Francisco, CA 94107, United States.
- Contact: bonjour@agencedebord.com.
Questions, corrections and complaints go to that address, and we would rather hear that a number is wrong than not hear it.
Personal data
There is no form, no account and no tracking cookie on this site. It does read an approximate location from your network connection in order to draw your UV curve, and the companies that host the site and supply the forecast keep their own logs. The privacy page sets out exactly what is sent, to whom, and for how long it is kept.
Changes
These terms may change as the product does. Continuing to use the site or the app after a change means accepting the version published here.