Residents living near the Duck Creek Pilliga Forest outside Narrabri have faced two days of emergency warnings as the fire swelled to cover nearly 130,000ha.
But the fire threat was downgraded to "advice" level - the lowest rating - shortly before midnight on Wednesday after thunderstorms earlier caused erratic behaviour from the blaze.
The bushfire was being brought under control later in the morning following more than 27mm of rain at Narrabri overnight.
"The fire is by no means out, however given the fire behaviour in recent days (the) weather is a most welcome change," the NSW Rural Fire Service said.
More than 400 firefighters were involved in battling blazes in the region overnight.
The bushfire remains about 17km south of Narrabri, which is home to more than 12,000 people, and 20km west of Boggabri.
Residents in the areas of Willala, Goolhi, Rocky Glen, Jack Creek, Bohena Creek, Stannix Park and Wynella were all warned to stay alert and continue monitoring fire conditions.
Building-assessment teams were not able to access the fireground on Tuesday due to the dangerous conditions.
The RFS says the fire is 'by no means out' but the change in weather is welcome. (HANDOUT/SHANE ALLAN)
Emergency Services Minister Jihad Dib said the change in weather gave firefighters a chance to put out fires and build containment lines.
But current El Nino conditions increased the risk of further fires due to high temperatures and dry weather, he added.
RFS deputy commissioner Kyle Stewart said the Pilliga Forest blaze was a good example of the danger of major bushfires over summer.
"Fuel loads, weather conditions and certainly what it is that we see in areas that are remote like the Pilliga hamper the ability for us to contain and control fires as quickly as we would like," he said.
But please be assured that what we know of the fire potential is being matched with the allocation of resources across the state."
Shane Allan's parents own Bohena Pet Motel on the Newell Highway, south of Narrabri, and he told AAP the rain came as a major relief as trees along the property boundary began to ignite.
"It was just starting to bust through our border coming past our fence, and then the storm hit," he said.
"Mother nature came to our rescue. You couldn't have planned it any better."
Mr Allan thanked RFS volunteers, describing them as "absolute legends" who put their lives on the line to help others.
There were 52 bush and grass fires burning across NSW on Wednesday morning, including four that were out of control.
30°C