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I made a small little web app calculator for myself and my family to figure out how long we could stay outside without needing sunscreen based on current UV and

I made a small little web app calculator for myself and my family to figure out how long we could stay outside without needing sunscreen based on current UV and skin type. I use it daily in the summer and a couple thousand people use it every month also. You can check it out at https://sunburntimer.com https://sunburntimer.com. It's also free and open source software, github link in footer.

Arubis 3mo ago
Denver, CO, USA resident here -- this looks _super_ useful and I'm likely to start using it heavily. Our weather here is usually very outside-encouraging (if getting hotter over the years) and our UV is _ridiculous_; I see the index hit 11 and 12 with some regularity. Thanks for the link!
- mreid 3mo ago
  laughs in Australian https://www.bom.gov.au/climate/maps/averages/uv-index/?period=jan https://www.bom.gov.au/climate/maps/averages/uv-index/?perio...
  - wil421 3mo ago
    The map isn’t too far off for July[1] considering how far Australia is from the Equator[2]. My area is similar to Sydney in your map. For Denver it’s the elevation that’s exposing them to more UV rays. [1]https://www.epa.gov/sunsafety/sun-safety-monthly-average-uv-index-2006-2023#tab-7 https://www.epa.gov/sunsafety/sun-safety-monthly-average-uv-... [2]https://www.reddit.com/r/MapPorn/comments/cd1t54/relative_latitude_of_australia_compared_to_north/ https://www.reddit.com/r/MapPorn/comments/cd1t54/relative_la...
    - Arubis 3mo ago
      Yep, this—we aren’t as close to the equator, but there’s less atmosphere to filter UV. Not so much in terms of beach days, of course, so sunburns here tend to be less than full-body. All that said: a daily mean of 13-14 is past what we’d see here—and yeah that is some serious burning.
hankbond 3mo ago
This is awesome thank you for making this!
fullykubed 3mo ago
Looks like the weather might be a bit off, I imagine from your upstream provider. In Indianapolis, all stats look correct except it says we have thunderstorms. Couldn't be a clearer day and nothing on the radar.
eurleif 3mo ago
It would be useful to have an option to change the time of day, rather than always using the current time; e.g. for planning at night what to do tomorrow.
- tele_ski 3mo ago
  I came here to post this so glad I'm not the only one looking for specific time of day. Or at least give the user the estimated time they can be outside before getting burned? The timer feels great to fire and forget but I might want to plan and I couldn't figure out from the UI what the duration is "safe"
  - eurleif 3mo ago
    It looks like the "Skin Damage Over Time" chart is the same information as the timer.
ahmadalli 3mo ago
Awesome project! I wanted its Home Assistant equavelant and there's an official integration for it: https://www.home-assistant.io/integrations/openuv/ https://www.home-assistant.io/integrations/openuv/
tuckwat 3mo ago
This is neat if you are avoiding the "getting red". My understanding is that the damage occurs with or without the sunburn but maybe this goes without saying.
giwook 3mo ago
This is a clever idea. Unfortunately, UV exposure is cumulative. So your skin is still getting damaged by the UV rays even if you're not getting burnt.
- TurdF3rguson 3mo ago
  Cumulative but with a repair mechanism. There's not necessarily "rollover exposure".
  - littlexsparkee 3mo ago
    There are temporary as well as permanent effects and the repair mechanism can be overwhelmed: photoaging, age spots, mutations.
    - TurdF3rguson 3mo ago
      Right but there are common precautionary rule-of-thumb heuristics which lead normal people to believe that every sun exposure brings them a little closer to death. That's exaggerated. Or at least, the claims are widely contested.
      - chiply314 3mo ago
        Lets be honest here, every additional sun exposre means you lived longer which directly leads you closer to death sooooo ;P
        TurdF3rguson 3mo ago
        That part really is cumulative
- smallpipe 3mo ago
  So how many Joules can you safely sustain in say, a month, or a lifetime ?
rasso 3mo ago
Amazing idea! A little Feedback: I tan easily but still have freckles.

Arubis 3mo ago

Denver, CO, USA resident here -- this looks _super_ useful and I'm likely to start using it heavily. Our weather here is usually very outside-encouraging (if getting hotter over the years) and our UV is _ridiculous_; I see the index hit 11 and 12 with some regularity. Thanks for the link!

mreid 3mo ago
laughs in Australian https://www.bom.gov.au/climate/maps/averages/uv-index/?period=jan https://www.bom.gov.au/climate/maps/averages/uv-index/?perio...
- wil421 3mo ago
  The map isn’t too far off for July[1] considering how far Australia is from the Equator[2]. My area is similar to Sydney in your map. For Denver it’s the elevation that’s exposing them to more UV rays. [1]https://www.epa.gov/sunsafety/sun-safety-monthly-average-uv-index-2006-2023#tab-7 https://www.epa.gov/sunsafety/sun-safety-monthly-average-uv-... [2]https://www.reddit.com/r/MapPorn/comments/cd1t54/relative_latitude_of_australia_compared_to_north/ https://www.reddit.com/r/MapPorn/comments/cd1t54/relative_la...
  - Arubis 3mo ago
    Yep, this—we aren’t as close to the equator, but there’s less atmosphere to filter UV. Not so much in terms of beach days, of course, so sunburns here tend to be less than full-body. All that said: a daily mean of 13-14 is past what we’d see here—and yeah that is some serious burning.

hankbond 3mo ago

This is awesome thank you for making this!

fullykubed 3mo ago

Looks like the weather might be a bit off, I imagine from your upstream provider. In Indianapolis, all stats look correct except it says we have thunderstorms. Couldn't be a clearer day and nothing on the radar.

eurleif 3mo ago

It would be useful to have an option to change the time of day, rather than always using the current time; e.g. for planning at night what to do tomorrow.

tele_ski 3mo ago
I came here to post this so glad I'm not the only one looking for specific time of day. Or at least give the user the estimated time they can be outside before getting burned? The timer feels great to fire and forget but I might want to plan and I couldn't figure out from the UI what the duration is "safe"
- eurleif 3mo ago
  It looks like the "Skin Damage Over Time" chart is the same information as the timer.

ahmadalli 3mo ago

Awesome project! I wanted its Home Assistant equavelant and there's an official integration for it: https://www.home-assistant.io/integrations/openuv/ https://www.home-assistant.io/integrations/openuv/

tuckwat 3mo ago

This is neat if you are avoiding the "getting red". My understanding is that the damage occurs with or without the sunburn but maybe this goes without saying.

giwook 3mo ago

This is a clever idea. Unfortunately, UV exposure is cumulative. So your skin is still getting damaged by the UV rays even if you're not getting burnt.

TurdF3rguson 3mo ago
Cumulative but with a repair mechanism. There's not necessarily "rollover exposure".
- littlexsparkee 3mo ago
  There are temporary as well as permanent effects and the repair mechanism can be overwhelmed: photoaging, age spots, mutations.
  - TurdF3rguson 3mo ago
    Right but there are common precautionary rule-of-thumb heuristics which lead normal people to believe that every sun exposure brings them a little closer to death. That's exaggerated. Or at least, the claims are widely contested.
    - chiply314 3mo ago
      Lets be honest here, every additional sun exposre means you lived longer which directly leads you closer to death sooooo ;P
      - TurdF3rguson 3mo ago
        That part really is cumulative
smallpipe 3mo ago
So how many Joules can you safely sustain in say, a month, or a lifetime ?

rasso 3mo ago

Amazing idea! A little Feedback: I tan easily but still have freckles.