Rain has returned to parched areas of eastern NSW this week, with some places receiving their best falls so far this year during the last 24 hours.

After the seventh driest May on record in NSW, onshore winds feeding into a low pressure trough have caused a mild and showery start to winter in the state's east.

Image: Visible satellite/radar image showing the cloud and rain over eastern NSW on Wednesday morning.

The wettest parts of the state so far this month has been the exposed Hunter coast north of Newcastle, where Nelson Bay registered a whopping 219mm of rain during the six days ending at 9am today. This is well over the site's long-term monthly average of 156mm for June.

Nearby, Forster's running monthly total of 100mm by 9am today is only 13mm short of its June monthly average. This is also nearly as much rain as Forster received during April and May combined (111mm).

During the 24 hours to 9am on Wednesday, Yamba's 39mm was its heaviest daily total in eight months, while Bega (32mm) received its best fall since December. Elsewhere, Kiama (39mm), Sydney (33mm) and Gosford (45mm) all registered their best daily rainfall in three to four months.

The maritime winds during the past few days have replaced much drier and warmer westerlies that frequented eastern NSW during May.

Sydney's running average maximum temperature during the first five days of June was a near-normal 17 degrees. This is five degrees cooler than the city's average maximum temperature during May, which was the city's fifth warmest on record for that month.

Sydney only reached 15 degrees on Tuesday and is forecast to reach 16 today. This would be the city's coolest pair of days in a year.