Let's See...
in the morning:
from sunrise to noon
- Good morning: صباح الخير (Sabah al-kheir)
- Response: صباح النور (Sabah an-nūr)
There are more colloquial variants on صباح الخير/النور that you can use, like :
- صباح القشطة (Sabah il-'ish-Taa - lit. morning of cream)
your resonse in this case may be: sabah el assal (morning of honey) or you can say sabah el nur .- صباح الفل (Sabah il-full - lit. morning of jasmine),
- صباح الورد (sabah il-ward - lit. morning of rose).
- They're a little "baladi" (i.e. used more by the rural and lower classes), but you can still use them to add some color to your speech.