January feeling refers to an emotional state characterized by feelings of optimism and possibility, particularly at the start of a new year.

“一月心情”是指新年伊始之际，对一切抱持乐观态度，认为所有事都充满各种可能性的心理状态。

There's another sense of this expression that means almost the opposite: An emotional state characterized by feelings of melancholy and lethargy, particularly early in the year when the holidays are over and a long winter looms. But this sense is quite old, dating to at least the mid 1920s.

该词还有几乎相反的另一种用法：指人们处于忧郁悲伤、无精打采的心理状态，尤其当人们年初休完假，仍处于漫长冬季的时候。不过，这种用法较为陈旧，至少可追溯到十九世纪20年代中期。