Light rain has fallen across parts of New South Wales including on some firegrounds, and while not significant, it has been greeted with joy by communities under threat from bushfires.

Key points: Light rain across NSW will do little to help with bushfires but more rain is expected

Light rain across NSW will do little to help with bushfires but more rain is expected The RFS says 136 fires are still burning, 59 of those uncontained

The RFS says 136 fires are still burning, 59 of those uncontained Bushfire crisis has caused havoc on the Katoomba tourism industry

The Blue Mountains mayor, Mark Greenhill, posted a photo of himself with a Rural Fire Service (RFS) volunteer under a cloudy and grey sky after erratic fire conditions eased early this morning.

"There is strange stuff falling from the sky! Rain!" Mr Greenhill said.

"We are not out of the woods yet, but I feel happier this morning than I have for a while."

Although the rain had stopped by midday, fog and cool conditions were still lingering in the mountains region.

It was the second bit of good news for residents in the Blue Mountains after winds predicted to whip up fires south of the Great Western Highway overnight, were not as strong as predicted.

Mist clouds in Katoomba this morning as fire conditions eased on a cooler day. ( Facebook: Gallery ONE88 Fine Arts )

Agata Imielska from the Bureau of Meteorology (BOM) said the rain is only in patches.

"For the most part we're looking at falls below 10 millimetres which unfortunately won't do too much, but certainly wouldn't be wishing the rain away," Ms Imielska said.

There have been more significant localised falls over the past three days, generally associated with thunderstorms.

Cooler temperatures are expected to last for the next week and no extreme fire danger days are expected.

Ms Imielska said there could be some more rain ahead.

"We are seeing some possibility of rainfall, some chances of thunderstorms later in the week.

A misty morning at Mount Wilson in the Blue Mountains. ( Supplied: Bryce Waters )

"There is a bit more of a rainfall signal coming through, how significant that will be, we'll have to check in later in the week."

The RFS said despite cooler conditions on Saturday, there were still 136 fires burning, 59 of those uncontained.

It told the ABC the small amount of rain was unlikely to have any meaningful impact on the fires burning in the mountains.

In fact, it could complicate backburning operations planned for the week by adding too much moisture to fuel loads.

But despite the middling amount of rain, it has done wonders for the morale of residents who have been anxious about the firestorm burning at their doorsteps.

Victor Peralta and his wife own an art gallery in Katoomba, which is currently surrounded by two massive blazes, and have lived in the region for over 30 years.

He said it was "jacket weather", although the acrid smell of the smoke was still hanging in the air.

The Blue Mountains region has been under siege from flames for months. ( ABC News: Brendan Esposito )

"The weather is gorgeous, nice and cool and damp," he said.

"The town was a little bit more alive today than it was last week, there's even a bit of traffic on the road."

He said the past few weeks have wreaked havoc on the tourism industry in Katoomba, with some businesses experiencing up to 50 to 60 per cent loss of visitors.

"It's been a ghost town for us, this should be the busiest time of the year," Mr Peralta said.

Some local businesses, he said, could take up to a year to get back on track.

A fire south of Wentworth Falls Table burning on Friday evening. ( Supplied: Twitter: Nano entity )

"Some other places won't recover at all."

Mr Greenhill said the cool mists have been a much-needed reprieve.

"I know firefighters who still have Christmas presents under their Christmas trees," he said.

"For me, these two days of rain will be a gift to a very weary community."

Both the community and volunteer firefighters working to protect properties were exhausted, but the mayor said they were trying to keep their spirits up.

"The spirit, the sense of humour, that sort of knockabout larrikinism is just always there and I think it's a great way of coping."