充满希望，乐观积极的“一月心情”

俗话说，新年新迹象。在人们的观念里，随着新年的到来，周遭事物也跟着焕然一新，为我们带来希望和快乐。由于新年伊始是一月，这种乐观心理也因此得名“一月心情”。

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。

For example:

Is it just me or are you all looking forward to the end of 2015? Something about that fresh new January feeling — all things seem possible!
是只有我一个人有这种感觉，还是你们大家都在期盼迎来2015年年末？这是某些关于全新的“一月心情”，即一切似乎皆有可能！

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。

For example:

Anyone who wants to lose "that January feeling" and substitute for that exhiliration and reinforced vitality, I recommend to go to the Exhibition of Canadian Art, open at present at the City Art Gallery.
我推荐那些想摆脱“一月心情”，恢复幸福快乐、生机盎然的状态的人去参观目前正在城市美术馆展出的“加拿大艺术展”。

（中国日报网英语点津 丁一）