It doesn't get real cold down in South Australia. Maybe 35-40f. I work shift work & ride to work in all weather. Dririder jacket, jeans, leather sneakers(no boots) & Black Ice gloves. Shivering helps to keep warm lol.
The other end of the scale is 110f + The only difference is that I change to summer gloves & don't wear a jumper under my jacket. If you ride fast enough you keep cool.

 

I wish it was cold here. 38deg C (104F) today

 

Long johns, wool socks, sweater, jeans, boots, snowmobile suit with light jacket underneathbalaclava, helmet, winter riding gloves should be good down to20 degrees F, maybe lower. The only part of me that was cold after 140 mile ride in those temperatures was my feet - the cowboy boots I was wearing just didn't quite do the trick. Heated grips, gloves, socks, vest should help although I've never tried any of them. I'm thinking about the socks and grips in case the urge to ride strikes this winter.

 

Good thing Perth is the only city on that side of Australia

 

Perth's a city?

 

Tour Master Transitions jacket, Ballistic 5.0 pants, Cold front carbon gloves and Alpine stars. All this over a set of Under Armor cold gear and I ride if it's 20f. I'm getting some Widder heated gloves this week so it should be even more comfortable. I have a 27 mile commute and my hands start to get cold when I am just about at my destination.

 

It doesn't get cold here in southern california. But for what its worth in th cooler part of the year I wear a fieldsheer wind blocker suite under my one piece leathers. A neck gator to keep the wind out of my neck area and some field sheer cold weather gloves. If ie gets a bit out of the norm I just put on a layer over my leathers and I am just fine.