French is gendered, arbitrarily so.
For example, the word ’moustache’ is feminine, while ‘soutien-gorge’ (bra) is masculine, which never ceases to amaze my female students!
To talk about ‘morning’, ‘evening’, ‘day’, and ‘year’, we have the choice between the masculine and the feminine version of those words, which invariably, and understandably, confuses students.
When we use the masculine version ‘un matin’, ‘un soir’, ‘un jour’, and ‘un an’, we are referring to the unit of time, as in:
‘Les feux d’artifices du Nouvel An’ (New Year’s Eve fireworks)
‘chaque jour’ (every day)
'un matin sur deux' (every other morning)
When we use the feminine version ‘une matinée’, ‘une soirée’, ‘une journée’, and ‘une année’, we are referring to either a specific morning/evening/day/year, as in:
'Cette année, je vais apprendre le français' (I'm learning French this year)
or to the duration of said morning/evening/day/year, as in:
‘Toute la journée’ (the whole day)
'Pendant la soirée' (during the evening)
So if you meet French people this month, you will be greeted with a ‘Bonne année !’ (Happy New Year!), thereby wishing you happiness for the entire duration of this year, which is what I wish you all.