Original: As it moved slowly westward , Hurricane John continued to strengthen considerably in an increasingly favorable environment well south of the Hawaiian Islands ; on 22 August John was designated a Category 5 hurricane on the Saffir-Simpson Hurricane Scale ( the highest classification for hurricanes ) and later that day ( by Hawaii Standard Time ) reached its peak winds of 175 miles per hour ( 280 km\/h ) .
Simplified: Hurricane John continued to strengthen , and reached a peak of 150 knots ( 175 mph winds ) on the 23rd , passing 300 nautical miles south of Hawaii .