Yeelight night and day mode

Hi everyone, I havn’t much experience with HA yet, but I’m trying to learn!! I’m faced with a new need: I have Yeelight lamps dimmed in RGB. they light up when passing by. I would like to make it so that during the day they turn on 100% white and at night in night mode (or with another color) and 20%. I tried using scenes but as soon as I activate the scene they just turn on. How can it be done?