Welcome rain continues to dampen drought-affected parts of eastern Australia, while parts of Sydney receive their best rain in two years.

A slow-moving low pressure system and associated trough have caused rain and thunderstorms to spread across NSW and southern Queensland during the last two days.

After Australia's driest September on record and nine consecutive drier-than-average months in NSW, this week's rain is bringing some much needed relief to thirsty soil. However, it isn't breaking the drought.

In the state's central west, Dubbo collected 45mm of rain during the 24 hours to 9am on Friday, which was its heaviest rain since March last year. Nyngan (36mm) and Forbes (26mm) both received their best rain in 13 months.

In Sydney, Holsworthy's 43mm during the 24 hours to 9am was its best rain since June 2016. Elsewhere, Horsley Park (58mm) received its heaviest rain in 19 months and Observatory Hill in the city (44mm) registered its best rain since March.

While this week's rain has brought some much-needed respite to drought-affected parts of western NSW, it hasn't been heavy enough to eradicate the recent rainfall deficit.

As of 9am on Friday, Dubbo's running annual total was 181mm, which is still its lowest amount of rain to this point in the year since 1965. On average, Dubbo usually receives more than 440mm of rain between January and October.

Looking ahead, another low pressure trough could bring some more rain to western NSW during the second half of next week. However, the rainfall from this system is not looking to be as heavy or widespread as this week's was.