january
In Italian, 'gennaio' is the first month of the year and corresponds to January in English. It is used in the same way as in English, to indicate the first month of the calendar year.
January is the first month of the year.
This phrase states that January marks the beginning of the calendar year.
In January, the days begin to get longer.
This sentence indicates that after the winter solstice, the duration of daylight starts to increase in January.
My birthday is in January.
Here, the speaker mentions that their birthday falls in the month of January.