Never during mid day because it's the hotter moment of the day so the difference between the solution temps and the soil temps could shock her but also because watter will evaporate with the sun rather than beeing used by the plants , during night time is also a watering window to avoid indoor because the water will bring the relative humidity higger than usual and if the plants are flowering then you could experiment a bud rot , the best time is in the morning just before the light turns on , for exemple and as an outdoor grower too I was watering my plants at 5 pm and the sun was rising around 6pm