Tips for watching the bats exit their bat cave in Phoenix!
When: May through October, just after sunset. I watched the bats yesterday, according to weather.com the sun set at 7:25 PM and that bats didn't start coming out of the tunnel until around 7:45 - 7:50 PM
Where: NW side of the canal near the intersection of 40th St & Camelback you've got to walk back to the tunnel. We parked at 5080 N 40th St (there are tow signs, so park at your own risk) from there you walk West along the canal until you see a paved path branch off on the right. Follow the path to the tunnel. The tunnel is surrounded by metal gates. The best place to watch is the North side of the tunnel, that is the direction the bats fly in.
What to expect: They were smaller than I expected. They started coming out just one or two here and there. I sort of thought we were going to see them all exit in one humungous group. That didn't happen, but they do swarm a big once they get going.