A run of chilly weather mid-month, which saw inland areas transformed into a winter wonderland, is to blame. 

Below-average minimum and maximum temperatures saw the Bellambi and Albion Park weather stations record their coldest July in 18 and 16 years, respectively. 

‘‘It’s a bit of a mixture between those two sites, but both overnight and daytime temperatures were around one degree below average throughout the month,’’ Anthony Duke, a senior meteorologist at Weatherzone, said.

‘‘For Bellambi, the daytimes included one of the coldest July days in four years and basically [is] representative of much of the other stations across the Illawarra. 

‘‘It looks like places like Point Perpendicular [south of Nowra], Moss Vale also had certainly their coldest days in the 13 years of records at those places.’’

A 13.5-degree maximum on July 12 gave Bellambi its coldest seventh-month day since the mercury dropped to 12.8 degrees on July 13, 2011. 

Mr Duke said the Illawarra chill was indicative of the weather experienced across much of south-east Australia during July. 

‘‘A lot of it was to do with that cold snap that we had in the middle of the month,’’ he said.

‘‘One of the coldest mornings at Bellambi was the 4th of July - that was among a stretch of frosty mornings and about a week later we had a cold snap come through and bought a couple of cold days, so that’s the main reason for it.’’ 

As for Saturday’s mild conditions, Mr Duke said a cold front due to cross Australia’s south-east was directing ‘‘a little bit of warmth’’ from inland NSW and southern Queensland.

‘‘Ironically enough, the northern part of Australia has had almost record-breaking warmth ... that’s basically where the warmth [in the Illawarra] is coming from,’’ he said. 

Mr Duke said the effects of El Nino - generally involving warmer-than-average temperatures and a reduction in rainfall across south-eastern Australia - would be felt closer to Spring. 

Anyone with outdoor activities should make the most of Saturday’s weather, with rain likely at times on Sunday. 

Windiest day - 91km/h gust (26th)