How will I know if my roof was damaged during a storm?

The only way to know for sure how badly a hail storm or a windy monsoon rainstorm has damaged your roof is to ask a licensed, local roofer to climb up there and have a look.

Still, a few clues can alert you that you might need repairs. The first thing is to consider is that you might not know your roof has damage. The problems a storm creates don’t necessarily result in immediate symptoms like blown-off shingles or leaks—especially when there’s hail or ice but no rain. So you might not think the roof needs repairs, even if it does.
When hail the size of marbles hits your house, you’re more than a little likely to have a roof problem. Three tell-tale signs your roof needs attention: First, if a heavy hail storm or windy rain touched your neighborhood, chances are, it ruined your roof. Second, if you’ve noticed roofers working at your neighbors’ homes, you most likely need a roofer, too. Finally, if your car or the doors of your house have hail or wind damage, your roof probably does as well.
If your roof has gutters and downspouts, check the bottom of the spout for granules that have washed off of your shingles. If you see an excessive amount of mineral lying on the ground, that’s an indication of hail damage.

Older roofs are less tolerant of hail and other severe weather than newer material. If your roof is old and your house got hit by the hail, have it checked out.
It’s possible your roof might not be damaged. If none of the homes near yours is suffering and if the hail or wind in your area was light, you might be one of the lucky ones. A reputable contractor will tell you if there’s no damage, so work only with a roofer who has an Arizona contractor’s license and displays the license number on business cards. Ask to see the driver’s license of any contractor you’re considering and verify that the truck and contractor’s license really belong to the person you’re doing business with.