I've never seen one either. My understanding is there
are two. One in the morning and one in the evening.
I'm told it occurs just as the upper limb of the sun
appears or disappears, and must be viewed over
water.

Michael wrote
Since I'm asking I can't beat you out! But for once it gives Bart Sr. a
chance to participate.

How many types of Green Flash('s) is it possible to see in one day?
Define
each.

M.