At least in my corner of Tokyo, the daily high has been anything but. It's been getting more and more like winter.

Are you sure you're not thinking of a few days ago? There was the remnants of a typhoon over northern Honshu that brought warm air to Kanto for a day, and rose temps to a little over 70degF. The trade-off was that it brought strong wind. This late in the year, it was considered unusual and it set records for highest temperature in December.

I would think a temperature rise of that much (daily temperature lately has been around 50degF, so were talking a 27 deg rise) within a short interval would damage objects like glass and maybe plastics from sudden heat expansion.

Depending on the source of your information (which you didn't reveal), the anomaly could be explained as a temporary miscalibration, mistake in observation, or mistake in reporting. For the record I haven't heard anything about this in Japanese media either.