Of course winter does not happen at the same time throughout the world. Would be interesting to see if it does the same if asked in a language spoken in the southern hemisphere.
That's a great question. However, I'd suggest a different approach as:
1. Southern hemisphere is mostly water
2. Majority of the text online is in English
So maybe a better approach would be to geolocate the prompt in Australia, for example: it's December in Melbourne, Australia...
December in Melbourne (and most of Australia) is a wind-down month. Over the week between Christmas and New Years many jobs essentially stop as we have three public holidays (which will always fall on week-days) across six days and people tend to take the opportunity to travel and enjoy the nicer part of summer. People just don't put in the work in December.
So maybe a better approach would be to geolocate the prompt in Australia, for example: it's December in Melbourne, Australia...