Because Crimea is relatively warm, it's an interesting place worth visiting and, last but not least, there aren't that many options for Russians to go spend winter holidays in. The next work day is Monday
Now that I live in Miami, 50 degrees is cause to break out the warmest clothes you own. Definitely all relative.
Humans may acclimate to cool temperature by increasing brown fat, which in turn may lead to improvements in glucose metabolism. These changes can be dampened or reversed following exposure to warmer temperatures.
https://www.nih.gov/news-events/nih-research-matters/cool-te...
Ditto for Chicago. First 50° day of the year, and Oak Street Beach fills up.