The NSW State Emergency Service is warning Sydneysiders to brace for another damaging storm season this summer as new data reveals the city's worst-hit suburbs from last year.

NRMA Insurance data shows last summer was the most intense storm season in four years, with 61 per cent of all home insurance claims during 2018-19 triggered by storm damage. December was the worst month, with 86 per cent of claims resulting from storms including Sydney's worst hail storm in 20 years.

Suburbs in Sydney's north and west were the city's most storm-affected, while the Central Coast was also heavily hit. Berowra Heights, Castle Hill and Chipping Norton were the top three suburbs, followed by West Pennant Hills, Baulkham Hills, Casula, Quakers Hill, Berowra, Moorebank and Glenwood.

While the Bureau of Meteorology's severe weather outlook for this summer predicts an increased risk of heatwaves and bushfires, the potential for damaging storms remains.