There is no best time to play slots as the games are set up to random number generators dictating that each spin has no bearing on the the one prior or the won to come. However, some slots at online casinos are included in daily jackpots which have to be paid before a certain value is reached or by a certain time of day. Whilst it is not guaranteed to take many hours for these jackpots to drop, they do tend to be won quite close to the closing time.