I submitted info for where I live (Toronto) and a day in mid July, and it suggested 6 minutes exposure on a cloudless day. That seems like a reasonably safe duration.
On the advanced form, you can be more specific about how much of your body is exposed, what kind of skin you have, and more values to tweak for atmospheric conditions, which would allow you to calculate how much for regular t-shirt, shorts and baseball-cap attire while out walking your dog or whatever.
The result also tells you how long is too long for the given conditions. For my Mid-July Toronto example, 20 minutes is too long.
On the advanced form, you can be more specific about how much of your body is exposed, what kind of skin you have, and more values to tweak for atmospheric conditions, which would allow you to calculate how much for regular t-shirt, shorts and baseball-cap attire while out walking your dog or whatever.
The result also tells you how long is too long for the given conditions. For my Mid-July Toronto example, 20 minutes is too long.