If your temperatures are getting down to 32 degrees Fahrenheit (0 degrees Celsius), the long thread below has many customers reporting their battery doorbells don't stay charged in cooler weather that's well within operating temperatures.
IIt did get down to -2c last night so it may be that. I also have a new broadband router so will try a few things 1st before I blame the weather. Looks like that might be the issue though.
Google Nest Help has just published a new support page on "Cold weather battery issues in Nest cameras and doorbells":
"9to5Google" has this article today, Feb. 18, 2022:
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