dminder.ontometrics.com Vitamin D is something that individuals are commonly deficient in. While there are dietary sources beyond supplementation, we also can increase our vitamin D levels via sunlight exposure. But how much sun do we need? For how long? During the changing seasons, the sun also changes - so how do we really know what is effective? This is a wonderful FREE app that can help determine and track your exposure and correlate it to approximate vitamin D boosts.