UV Index
UV Index
Today's UV index in Nagasaki, Japan 
will be up to 11.9, indicating a extreme level of sun exposure for the average person. Check our tips for today to make sure you're safe in the sun.
Last checked: 2025-06-22
UV index at 11.9 in Nagasaki means extreme risk: limit outdoor time especially from 10 a.m. to 4 p.m., actively seek shade, wear protective clothing, broad-brimmed hat, apply SPF 30+ sunscreen every 2 hours, and wear UV-blocking sunglasses. Watch for bright surfaces like water and snow increasing UV exposure.
The UV index in Nagasaki varies throughout the year, reaching high levels in summer months, especially June through August, and lower levels in winter, from November to February. UV exposure is strongest during midday hours.
Nagasaki experiences warm, humid summers with frequent rain, especially during the rainy season in June and July. Winters are mild and relatively dry, with occasional cold spells but rarely snow. Spring and autumn have comfortable temperatures and less rain.
Compared to other parts of Japan, Nagasaki is milder in winter and warmer in summer due to its coastal location. It has more rainfall than northern Japan but less than tropical Okinawa. Neighboring South Korea generally has colder winters.
See the UV index hour by hour for Nagasaki, along with the temperature and how cloudy it is. If the UV level is higher than moderate, it's best to avoid direct sunlight.