NSW residents are being urged to prepare their homes for severe storms, with El Niño increasing the prospect of volatile weather in the months ahead.

September marks the start of the state’s high-risk weather season, when storms, strong winds and heavy rain typically become more frequent.

The NSW SES says El Niño can contribute to greater weather variability, with damaging winds, intense rainfall, large hail and flash flooding possible when conditions align.

Last storm season, SES volunteers responded to more than 23,000 incidents across NSW, including 18,905 storm-related emergencies.

About 7000 calls involved fallen trees, while more than 6500 were for leaking or damaged roofs.

Emergency Services Minister Jihad Dib said people should prepare before severe weather warnings were issued.

“Preparation is one of the most effective ways people can protect their homes and their families,” Mr Dib said.

“Now is the time to act, not after warnings are issued.”

The Bureau of Meteorology’s long-range forecast points to a tendency towards below-average rainfall at the start of spring, particularly west of the Great Dividing Range.

However, east of the Divide — including the Northern Rivers — the spring outlook is more variable due to warmer-than-average sea surface temperatures in the Tasman Sea.

The Bureau says individual coastal troughs and thunderstorms could interrupt otherwise dry periods, bringing heavy rainfall, damaging winds, large hail and flash flooding.

NSW SES Commissioner Mike Wassing said drier conditions did not remove the threat of damaging storms.

“Even in years where drier conditions may be expected, we can see severe storms with damaging and destructive winds, large hail, intense rainfall and localised flooding,” he said.

The SES is urging residents to clean gutters, downpipes and drains, trim overhanging branches and secure trampolines, outdoor furniture and other loose objects which could become dangerous in strong winds.

People should also review their household emergency plans, prepare an emergency kit and download the Hazards Near Me app.

For emergency assistance during floods and storms, call the NSW SES on 132 500. In life-threatening emergencies, call Triple Zero (000).