Sydney and much of eastern NSW can expect more thunderstorms following a rainfall over the weekend which brought more than 60 millimetres in some areas of the state.
Active showers and thunderstorms landed across NSW on Sunday, with a rainfall of nearly 61 millimetres since 9am in Bourke, in northern NSW, the highest recorded, a Bureau of Meteorology spokeswoman told AAP.
In NSW's mid-north, Girilambone recorded 42.2mm, while in the Riverina Griffith recorded 30.8mm.
In Sydney through to the Central Coast and the Hunter region, a combination of a wind change and rainfall are forecast to have a "very strong mitigating effect" on smoke caused by fires around the state, the spokeswoman said.
Smoke was on Sunday afternoon still present across areas of north-east NSW closer to fire activity.
This is expected to continue until at least Monday or Tuesday, when showers and storms as well as a wind change will mitigate the smoky conditions, the BOM spokeswoman said.
Sydney and much of eastern NSW are expected to see a continuation of thunderstorm activity on Monday.
NSW RFS Inspector Ben Shepherd told AAP the showers "will give us a little bit of reprieve from the fire dangers we've seen over the last few days".
The agency would have a clearer idea on Monday "about what got what and then where our risks are".
By Sunday afternoon there were still around 70 fires burning across NSW, at least half of which were uncontained.
The far North Coast, North Coast, greater Hunter, Monaro alpine, New England, Northern Slopes and north western regions have been given a high fire danger rating for Monday.
The Department of Environment has given Sydney an air quality forecast of "good" for Monday after it reached "poor" earlier in the week.
Australian Associated Press