Clouds reduce UV, but it still penetrates (also, apparently, it can actually enhance UV at times [0]). In my country (New Zealand), in summer you can get sunbur

Clouds reduce UV, but it still penetrates (also, apparently, it can actually enhance UV at times [0]). In my country (New Zealand), in summer you can get sunburned in about 10 - 20 minutes on a cloudy day, compared to 5 - 10 minutes on a clear day. But then, we tend to have much thinner ozone above us in our summer than countries in the Northern Hemisphere.[1] [0]: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2004RG000155 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2004RG00... [1]: https://www.nasa.gov/topics/earth/features/ozone-aus.html https://www.nasa.gov/topics/earth/features/ozone-aus.html