My bunnies were always kept outside as kids and we lived in the highlands of Scotland.
A decent sized hutch in a sheltered corner, a couple of old blankets from a thrift shop and a tarpaulin weighted at the front, put the blankets on so it covers the entire hutch then cover with the tarpaulin, put weight on the top, put a couple of old socks on the water bottle to help keep the water bottle flow.
Each morning fold back the tarp from the front and tuck the blankets up in the front leaving the rest of the hutch covered.
Our rabbits and guinea pig lived till 8 plus like that.