1) Ideally one should make sure to say all of the morning blessings before the final time for praying. If he did not make these blessings before then, he may make them until midday. There are however, opinions who say that if necessary one can make these blessings all day, and even at night until he goes to bed. One who relies on this opinion, is not wrong. (Shulchan Aruch 52)

2) Even according to the above opinions, if night has fallen and he is already tired and falls asleep. He may not make “Hamaavir  chevlei sheinah”. (ibid)