3 flats in 650 miles (1030 km) on hybrid bike. Tire pressure wrong?
Depending on your attentiveness while riding, the hazards in the area you ride in and a few other factors, that may be a reasonable amount of flats.  I know a few commuters in my area that expect roughly a flat a week in their roughly 100 mile weekly commute.  I've ridden with this particular pair of guys, however and found they have a tendency to shortcut through glass filled abandoned parking lots and the like, and they don't pick careful lines through that mess.

I will say this about flats, when you change a flat, you should always figure out why/how you got the flat.  If you don't, you'll just get the same flat again.  Pull the tube, keep it oriented, re-inflate it and figure out where the hole(s) are.  There are articles out there telling you where to look based on the placement of your tube holes and their configuration.  If you are getting repeated puncture flats from objects, you may consider switching to more puncture resistant tires.  Keep in mind more expensive does not mean more durable.  I've bought ultralight and expensive race tires before that didn't make it 13 miles around a loop before picking up 3 punctures from gravel that wasn't even that sharp.  I ended up switching to a much heavier but more puncture resistant tire that was 30% cheaper and hasn't had any punctures since.  I don't race, so that works fine for me.

If your awareness doesn't keep you out of glass patches and the like (or they are just unavoidable in your area, I am pointing at you Honolulu) and you get repeated puncture flats, you may also consider switching to a tubeless setup with juice in your tires to minimize the impact of these.