Let's first answer a few questions about your situation...
What time is your venue available?
Have you left enough time for set-up?
Will you be taking your photos before or after your ceremony?
Either way allow a min of 1 hour (if staying onsite) up to 3 hours.
What time does it get dark where your getting married?
Daylight savings? Allow time for photos if getting them taken after the ceremony.
When is your venues curfew?
It's usually midnight but can be 11pm or 1pm. Or what time to you want to finish up and leave?
Is your ceremony at the same location as your reception or will your guests have to travel?
How long for? Consider parking & getting in and out of car etc which can add a further 10-20mins.
On the flip-side...
How long will your make-up & hair take?
Bride usually 1 hour, bridesmaids 1/2 hour each.
How far do you have to travel to get to your ceremony?
Again add the getting in and out of car time.
Now we have a fairer idea of what you have in front of you and what you want to do with it, let's look at the timeline of a typical evening reception.
5.30 pm- Cocktail hour
6.30 pm- Welcome & seating
7.00 pm- Entree
7.30 pm- Main/ Speeches/ Cutting of the cake
8.30 pm- Desert
9.00 pm- First Dance followed by dancing
Midnight- Finish up
Working from this schedule and taking in my humble opinion here are my perfect ceremony recommendations based on a 1/2 hour ceremony leaving room for a bride running a little late & a few family photos after the ceremony...
If having photos prior to ceremony: 4.00 pm- 4.30 pm
If having photos after ceremony: 2.30 pm- 3.30 pm
Of course you can get married at dusk or midnight or any other time you'd like!