If you follow the "normal" schedule of sleeping (i.e. you don't work nights or something), then this probably has more to do with the deeper stages of sleep bei

If you follow the "normal" schedule of sleeping (i.e. you don't work nights or something), then this probably has more to do with the deeper stages of sleep being more common at the beginning of the sleeping session and REM sleep more common as sleep duration continues. As a person who induces lucid dreams as a hobby, I sometimes manage to make use of those long lazy mornings on weekends to lucid dream. I've found it's very difficult to have a lucid dream in the first two or three sleep cycles. After that, it's much easier because the REM stage of sleep is longer. Not that I've found that having lucid dreams is easy, I get one day like that every month or two and a spontaneous one here or there in between.