At least 20mm of rain overnight dampened activity across the fire ground near Bermagui and enabled crews to strengthen containment lines on Thursday, the NSW Rural Fire Service said.
Hotspots were being extinguished near Cuttagee and Barraga Bay as mopping up continued further south for the Bega Valley bushfire.
"Firefighters are back out on the ground today, making sure we're taking care of smouldering logs and dangerous trees," RFS spokeswoman Victoria Quested told AAP.
While the fire is being contained and cooler conditions are expected to remain for several days, the RFS warned an increased risk of falling trees and pockets of active fire remained.
Strengthening winds on Thursday may also lead to some reignitions within the burnt area, it said.
At least four homes and a shed have been found destroyed, but that number could increase as assessment teams complete their survey of the area.
At 6700ha, the fireground is now more expansive than Sydney Harbour.
The bushfire was brought under control overnight after spreading rapidly in hot, windy conditions on Tuesday.
Bega Valley residents will have access to disaster assistance under Commonwealth-state recovery funding arrangements.
NSW Emergency Services Minister Jihad Dib said the assistance would support communities, landowners, farmers and primary producers in the clean-up and recovery after the bushfires.
There were 42 grass and bush fires burning across the state early on Thursday afternoon, while high fire danger ratings were in place for the greater Sydney, Hunter, north coast, northern slopes and northwestern regions.
Premier Chris Minns, who met with emergency service workers in Bega and Bermagui on Wednesday, warned of a "horror summer" ahead.
"The real risk from the last 48 hours is that much of the area that has been affected by bushfires has been the same area that was burned out in the 2019-2020 bushfires," he said.
"It means there's a significant load that's regrown enough to have a bushfire go through it and that's a concern for the Rural Fire Service and for those communities."
Temperatures were expected to be close to the October averages across much of the state, but damaging winds hit the north, central and southern ranges and parts of the south coast in the morning.
Wind-damaged roofs and fallen trees sparked most of the 291 responses from SES volunteers in the 24 hours to midday Thursday, including 113 incidents in the state's north.
Sandbagging was also occurring near the Victorian border amid riverine flooding.
SES assistant commissioner Sean Kearns praised the public for heeding safety warnings amid wild weather, with no reports of injuries or rescues.
Strong winds also caused widespread flight cancellations at Sydney Airport, where only a single runway was in use due to the gusty conditions.
More than 100 domestic departures and arrivals were listed as cancelled as the runway restriction meant nearly half of all scheduled flights would not be able to operate.
