Current methods to promote awareness of the sun's ultraviolet (UV) radiation have focussed on delivering population level information and some location-based reporting of UV Index (UVI). However, diseases related to excessive (e.g. sunburn, skin cancer) or insufficient (e.g. vitamin D deficiency) exposure to sunlight still remain a global burden. The emergence of wearable sensors and the application of persuasive technology in health domains raise the possibility for technology to influence awareness of sufficient sun intake for vitamin D production, as well as preventing risk of skin damage. This paper presents a personalised solution to promote healthy, safe sun exposure using wearable devices and persuasive techniques.