iMac and cold temperature concerns

HI Justakiwi, I'm over on the West Island 😃 in Melbourne, although a bit further north than you are. I've been to Hobart in late winter and, although not much colder than here, must be similar to your location so I can understand your conditions.

The tech specs of the 24-inch, M1, 2021 in the section Electrical and Operating Requirements gives the safe operating temperature environment as 10° to 35° C.

My study in which my iMac is located gets cold in winter and in July in particular it can get very cold overnight. I don't heat unoccupied rooms during the evening and never overnight, unless we are taking about the living room where the cats might be sleeping. In summer it often gets over 40° which is again above the quoted temperate range which Apple recommends. I've never had any problems with my hardware in these conditions.

How cold does it get for you without heating? In your situation I'd also pack the Mac away in its box to isolate it a bit from the conditions inside your van when you're away.

Web search funds:

Electrical and Operating Requirements

• Storage temperature: –40° to 116° F (–40° to 47° C)
• Relative humidity: 5% to 90% noncondensing
• Operating altitude: tested up to 16,400 feet (5000 meters)

You need to consider relative humidity too. And, tech specs can change.

The link I provided for Eve Weather is from the New Zealand Apple Online store, so you ought to be able to get it locally from there?

Sleep should be all you need to do. If you also have a Time Machine external drive attached and Power Nap enabled in System Preferences > Energy Saver your Mac will be active during the night doing the backups. Power Nap also allows the Mac to check for new email, calendar and other iCloud updates. All of which will warm it up a bit too.

Regarding humidity, I have an Eve Weather station which would do the job. It's sold in the Apple Store NZ.