Those hoping for a long hot mostly sunny summer on the beaches and playing fields of Sydney may be in for some disappointment.

The latest outlook from the Bureau of Meteorology for November to January points to the odds beginning to shift to average or wetter than average conditions for most of south-eastern Australia.

Shape of things to come?: A weak shelf cloud forms off Sydney's eastern beaches. Credit:Nick Moir

Along with the higher chances of rainfall for the region, including for Sydney, the extra cloud cover will probably moderate daytime temperatures while making nights warmer and stickier than usual.

Cooling in the equatorial Pacific is tilting towards a La Nina, the bureau said this week, conditions that typically favour more onshore, moist winds for eastern Australia.