It's spring?

It was too warm today.
It is almost spring....?
Wait! Today is the 31st of January!
The maximum temperature was 15 degree Celsius
in Maebashi city today.

The Haruna lake in Gunma has not been frozen over.
There is a famous lake that is fishing pond smelt.
However, this year, anglers cannot go fishing there.
It is a case of unprecedented magnitude.