Three-year-old Dayvhen Lupica, right, cooled off with his brother Daysen, 6, Sunday with a water hose and a plastic bin outside their family residence in Manoa. The National Weather Service predicts sunny skies all week, with a high of 86 degrees. Today’s ultraviolet radiation index for Honolulu is 12, considered “extreme” exposure, and is unmatched across the country except by Albuquerque, N.M., and Puerto Rico, the weather service said. Light tradewinds today will increase through Tuesday as a high-pressure system far north of the islands becomes stronger. Some showers are expected, mostly at night and in the morning.