UV Index at Toko Mouth

New Zealand has some of the highest UV radiation on Earth. The ozone layer over the Southern Ocean is thinner, and the summer sun angle is steep. At Otago latitudes, summer midday UV can reach 10-12. The clean southern air also lacks the haze that attenuates UV in more polluted regions.

NZ's SunSmart message: Slip on a shirt, Slop on SPF 30+ sunscreen, Slap on a broad-brimmed hat, Wrap on sunglasses. Protection is needed whenever the UV index is 3 or above.

Cloud does not eliminate UV. Thin or broken cloud can still transmit 80-90% of UV radiation. Even on overcast summer days, UV can reach moderate levels. Sand and water at Toko Mouth can increase effective UV dose by up to 25%.

Summer (Dec-Feb) peak UV: 9-12 - Autumn/Spring: 4-7 - Winter (Jun-Aug): 1-3. Protection is generally unnecessary in winter. The September UV rise catches many people unprepared - it increases rapidly from the winter low.