Ok so the quick answer is...it depends.
Whether or not your insurance policy covers damage from hail ultimately boils down to the type of coverage you pay for. Comprehensive coverage for example will protect against a long list of damage causes, including hail damage and other weather-related claims. This coverage option is commonly recommended for most new and moderately used vehicles and those with liens. Another cheaper option is basic liability coverage, which is typically required by law and does not provide coverage against hail damage.
Some insurance companies protect themselves against projected hurricanes and other extreme weather, placing a hold on comprehensive coverage options for the geographic area expected to sustain severe damage. For this reason among others, it is not smart to wait until you actually need the coverage.
In extreme cases, which occur regularly throughout the United States each year, a car can be totaled by hail damage. The damage to window glass, windshields, and auto body can be serious. Depending on the vehicle's value, it may not be worth fixing it at all. An insurance adjuster will be the professional judge here, estimating the damage value and costs to repair. If you're filing a claim and speaking with your insurance company representative about what comes next, chances are you opted to pay extra for comprehensive coverage.
Storm damage remains almost impossible to predict, however various parts of the United States are more likely to see hail than others. If your vehicle is victim to hail damage, it is smart to start the claim process with your insurance company as soon as possible. Catastrophic hail events and storms for that matter wreak havoc, and the damage is often widespread. This means backlogs for the limited trained specialists who perform auto body work and paintless dent repair. In other words your car was probably not the only one affected. If you are slow to react it may take longer than usual to process your insurance claim and repair your vehicle.