I've just mowed my lawn - in the dark and at about 6°C.
Any reason why that could be a problem?
Do your neighbours give you odd looks?
Can't tell. It's too dark.
If the cars with blue lights turn up-don't answer the door
If anyone has a noisy petrol mower, then I would much prefer them to cut the lawns after dark, while I'm watching telly, than to disturb the peace on a Sunday afternoon.
It's very thoughtful and considerate of you.
Some people go out with a torch after dark to catch slugs and snails, so I think you'll be OK but don't make a habit of it.
Phytographer; Do you wear a miners torch, attached to your forehead?
I'd be sure to leave the lawn and mow the borders - but otherwise I can see no reason why not, though it sounds a tad chilly for me ..............