if you're growing in soil... in pots... it might be wise to water in the middle of the day. I am growing in 6 pots on my deck (in coco). I don't really pay attention to what time I water. I do it every other day. On hot days I will water (even if it isn't every other day) in the middle of the day... just to keep the roots from baking.
Indoors, while vegging, I water every 3 days. while blooming, every 2 days. Outdoors, while vegging I water every 2 days (evap increases outdoors). I don't bloom outdoors. Outdoor schedules are very general.
It doesn't matter much what time of day you water. Watering not only supplies nutes and moisture to your plants, it can also be a tool to keep things cool... especially in outdoor pots.