There are a number of factors to consider as you finalize your wedding-day timeline, including everything from the availability of your venue to the time needed to set up and the layout of your space. Before deciding on a start time for your ceremony, you'll want to consider the logistical details and your personal preference.
All venues have rules for how long and how late their event spaces can be occupied, and much of your wedding-day timeline will be based off these rules. For example, if you only have the venue for five hours and you know you want to party until ten o'clock, you'll likely begin the ceremony right at five o'clock to maximize your time. Private estates and some more boutique properties might give you the option of the whole day, allowing you to start earlier.
If you're planning an outdoor ceremony and cocktail hour, you might opt to base your timeline around where you'd like guests to be during sunset. Many couples prefer to have a sunset cocktail hour, but it depends on the time of year and how late the sunset is. For instance, during late fall in California, you could easily set your wedding ceremony time for five o'clock, kick off cocktails at 6 p.m., and head to dinner in the gardens just in time for sunset at 7 p.m.
A peak heat outdoor ceremony is something the majority of couples want to avoid, so you probably wouldn't plan on getting married outdoors between noon and 3 p.m. in the summertime. In the winter you'll want to shimmy the timing up a bit earlier so that your outdoor vows don't take place too close to nightfall.
Of course, there are many couples who prefer to go with alternative ceremony times. For instance, some swear by the romance of a sunrise ceremony while others might opt to exchange vows at the very end of the night during a New Year's Eve wedding. It's really a matter of personal preference and taking the whole wedding day timeline into consideration.