The winter weather record has tumbled as Sydney experienced its warmest July day on record with the temperature topping 26 degrees at Observatory Hill.

Scarves were traded for shorts as the mercury rose throughout the day, reaching 26.5 degrees at 2:10pm, creeping above the previous record of 25.9 degrees set on July 24, 1990.

Coogee Beach visitors enjoy the hot weather on Sunday. Credit:Katherine Griffiths

With the temperature reaching 18 degrees at Observatory Hill by 9am, many people headed to the beach where the water temperature was 18.7 degrees.

By noon, the temperature had hit 21.7 degrees before climbing to 25.9 degrees at 1:20pm, data from the Bureau of Meteorology shows.