The Bureau of Meteorology's Summer Outlook, released on Thursday, suggests daytime temperatures are very likely to be above average across Australia between December and February.

Senior climatologist Robyn Duell said there was "a very high chance" December would be drier than average in the region.

"Once we move into the new year, we're not seeing a strong push either way," she said.

"In terms of temperature it may be quite cool overnight in December.

"Over spring, nights have been cooler than average across the Wimmera, so we're expecting to see a continuation of that in December, but days are likely to be warmer than average. As we move into the January to March quarter it looks like it will be warmer across the days and nights."

Bureau data shows the average maximum temperature in Horsham to be 31.3 degrees in January. In December, the average minimum is 10.6 degrees.

The city sees an average of 25.6 millimetres of rain every December, 28.4 every January and 21.6 in February.

The climate outlook suggests much of the Wimmera has less than a 40 per cent chance of receiving above-median rainfall this summer.

Ms Duell said the Indian Ocean Dipole - sustained changes in the difference between sea surface temperatures of different parts of the Indian Ocean - explained the dry outlook for December.

"We also have what's called a negative Southern Annular Mode influencing Victoria.

"That's when we see westerly winds a bit further north than usual, and that tends to bring warmer and drier conditions at this time of year," she said. "That is expected to break down during the later summer months."

Ms Duell said for the Wimmera, spring in 2019 had been warmer and drier than average.

"For people for whom rainfall is important and for whom heatwaves can impact on their farming equipment and operations, we're seeing a continuation of warmer and drier conditions until the end of the year," she said.

She said the Australian Seasonal Bushfire Outlook put the risk of bushfires in the Wimmera this summer as similar to previous years, while there was an elevated risk of fires in eastern parts of Victoria.

While you're with us, you can now receive updates straight to your inbox twice weekly from the Wimmera Mail-Times. To make sure you're up-to-date with all the news from across the Wimmera, sign up below.