It is important to be aware of any events happening around the community or city on your wedding day that could conflict with your event. Depending on where you are getting married it may not effect you at all but here are a few examples that might get you thinking about what to look for to avoid any issues.
If you are getting married in a smaller city with limited accommodations, large events like University Graduations, Festivals, Expos, etc. could fill up all the local hotels and increase traffic. It can be complicated or impossible for your guests to find available rooms or rentals during that time. Not to mention rates tend to increase at these times due to the guarantee that the hotels will book up. You might consider shifting your wedding date to avoid this issue. Or get confirmed block booking from a few hotels. Also give your guests a heads up about the increase in street traffic so they leave with enough time to get where they need to be.
If you are getting married near an airport or military base, look into the dates of airshows or trainings. As this will cause an increase in noise from all the planes and jets flying over your venue. This could cause issues with sound and comfortability during your ceremony and reception. Don't be afraid to ask your venue if they experience a lot of noise from planes.
Another thing to look into is parking. Does your venue have limited parking? Or does it rely on parking garages (downtown venues)? If your wedding lines up with another downtown or community event that will fill up the parking garages, this could cause issue for your guests. To combat this as a struggle you could look into shuttle options for your guests, or ensure they have multiple parking options before the day comes.
Get access to a city or community calendar and look at that when choosing your wedding date. This will allow you to be prepared for any of these issues before they happen. The more prepared you are in advance to combat them, the easier it will be for you and your guests.