Without taking personal preferences or routine into account, the best time to shower is thought to be in the evening, an hour or two before bedtime.
This is considered to be the optimal time to shower from a hygienic perspective, as you’ll be nice and clean when entering your bed for a night time sleep, largely minimizing the spreading of germs collected throughout the day.
That said, there is also a multitude of benefits to taking a morning shower as well, and it is very much not a case of either/or regarding the best time to shower.
Further insight can be found in our blog, 9 Reasons You Need To Shower In The Morning.