The Bureau says the national outlook for total rainfall for September to November is neutral for most of the country, but there are mixed odds in parts of southern Australia.

It reports that a moderate to strong shift in the odds favouring above average rainfall in southwest Western Australia contrasts with the situation through parts of central and southern South Australia where a drier spring is the more likely outcome.

The pattern of seasonal rainfall odds across Australia is mainly a result of continued warmth in the central and southeastern Indian Ocean, especially off the west coast of WA.

The chances of exceeding the median rainfall for spring are between 60pc and 75pc over southwest WA, while the chances of exceeding the spring median are between 35pc and 40pc across a region of central to southern SA, roughly centred on Port Augusta.

However, over most of the nation the chances of a wetter than normal spring are between 40pc and 60pc, meaning that above average falls are about as equally likely as below average totals.

But the Bureau also says the national outlook for average spring maximum temperatures shows a moderate to strong shift in the odds favouring warmer than normal conditions over most of the tropics and parts of southern Australia.

The chances are mainly between 60pc and 75pc for above average maximum temperatures in northern Queensland, the northern two-thirds of the NT and the far north of WA.

In some areas near the Gulf of Carpentaria, the probabilities approach 80pc.

There are also 60-65pc chances for a warmer than normal spring in southwest WA, southeast SA, and western and central Victoria.

Across the rest of the country, the chances of a warmer than average spring are between 50pc and 60pc, indicating roughly equal chances for warmer or cooler than normal conditions.

Average spring minimum temperatures are also favoured to be warmer than normal across most of the country, with the exception of Queensland's southern half and the northeast half of NSW.