Summer heatwaves have led to extreme conditions for riders in recent years, and scorching temperatures in the Adelaide Hills played a significant role in the bushfires that devastated communities around the Tour route in recent weeks.

However, it was relatively cool throughout the women's race this week and the Bureau of Meteorology has forecast only one day with a maximum temperature in the 30s in Adelaide during the January 21-26 men's event.

Likely cloud cover and even some rain mean there is almost no chance the Tour heat policy will be required.

The forecast is for a maximum of 27C for Tuesday's 150km first stage through Tanunda and Angaston.

Riders are expected to enjoy some of the mildest conditions in the race's 22-year history.

"It's not really hot like last year," Italian sprint star Elia Viviani said.

"We have to wait until race week, but the first feeling of the first week is super.

"Good training, good track session, so the shape looks good and we just wait for the race."

Some European and North American riders in the women's peloton felt mild conditions had negated an advantage had by local Australian riders in hotter weather.

That belief held true on Saturday when American duo Ruth Winder and Lauren Stephens filled the podium with Germany's Liane Lippert for stage three.

Winder (Trek-Segafredo) snatched the ochre jersey from Australia's three-time defending Tour champion Amanda Spratt (Mitchelton-Scott) in the process.

Cofidis leader Viviani said current conditions would give riders a perfect launching pad into the 2020 season.

"When it's not extreme like last year you can train more and stay more hours on the bike and do more effort that you can't do when it's 40 degrees because your body is already suffering from the heat," Viviani said.

"I think the conditions help us a lot in this period.

'In Europe we are not more than 10-15 degrees in the best place.

"We've found good conditions here to train and put (kilometres) in our legs to be ready for the season."

Last year, extreme conditions marked the opening three stages of the men's race.

Rider agitation led to discussions between Tour officials and team leaders about whether the fourth stage should be shortened.

In the end, it went ahead as planned, but only after a narrow margin in a vote was announced at the last minute.

Australian Associated Press