UV Index 🇮🇩Indonesia

Indonesia straddles the equator from roughly 6°N in northern Sumatra to about 11°S in the Lesser Sunda Islands, stretching more than 5,000 kilometres east to west across over 17,000 islands. The sun passes near the zenith throughout the year, so solar elevation stays high in every month and the country sits within one of the broadest equatorial UV regimes on Earth. With minimal seasonal change in day length and a thin tropical ozone column, ambient ultraviolet remains intense across the entire archipelago.

Indonesia is the world's largest archipelago crossing the equator, and persistent tropical convection produces towering cumulus that drives strong day-to-day and hour-to-hour UV variability as clouds build through the afternoon. Altitude further raises exposure on volcanic peaks such as Puncak Jaya at 4,884 metres in Papua and Kerinci at 3,805 metres in Sumatra, where thinner air reduces atmospheric attenuation. BMKG, the national meteorological agency, issues an official UV index forecast, and the contrast between the wet and dry monsoons shapes cloud cover and surface UV from one region to the next.

Indonesia sits at #45 of 191 in the WHO's global ambient-UV ranking with about 5,220 J/m² of average daily UV, around the 77th percentile worldwide.