I installed an app a few months back called dminder that attempts to do exactly that. You pick your skin tone, it figures out your location, time of day, cloud

I installed an app a few months back called dminder that attempts to do exactly that. You pick your skin tone, it figures out your location, time of day, cloud cover and uses that to estimate the amount of vitamin D you can get based on the amount of time you're outside. Links: https://play.google.com/store/apps/details?id=com.ontometrics.dminder https://play.google.com/store/apps/details?id=com.ontometric... https://apps.apple.com/us/app/d-minder-pro/id547102495 https://apps.apple.com/us/app/d-minder-pro/id547102495