Nouns ending in -ude are usually feminine.
The suffix marks an abstract state or quality.
Is habitude masculine or feminine?
l'habitude
The rule behind it
92% of -ude nouns are feminine
In context
Je suis arrivé plus tard que d'habitude.
I arrived later than usual.
Je me lève d'habitude à six heures.
I usually get up at six.
Les étés j'allais d'habitude à Miami.
During summers, I used to go to Miami.