I'm in the San Francisco market, and we have pretty good results with evening open houses, usually on a Wednesday or Thursday, after work.  I usually do a wine & cheese showing, and I send out postcards to neighbors about a week in advance (I usually send them a few days before it's listed, and then do it the week after the first weekend open.)  This works especially well with higher end listings, but people love free wine and cheese, so I always get a good turnout.  For weekends, I typically see good turnout from 1-4pm, with a majority of people showing up at 4pm, so I never really get out of there until after 4:30.  I'll be trying to do a few 2-5pm opens and will see how those go.

Ki, I find that the best times for open houses in my area are right after church on Sundays.  Especially if the home I am hosting open is nearby a church.  If their last service is at 11:00, then I am there from 11:45 til around 4:00.  Most traffic will come in right after the service.  I also have a sign with balloons out on the lawn for the week leading up to the open house now, announcing it will be held open.

Ki I am in a suburban market and what I have found is that I get better results 12-2 closer to the loop and 3-5 farther out in the area.

Seems to me that if an agent bills his time at $XXX per hour, the open house should be when he has the best chance for a return on the investment of time.  That would clearly be Sunday.  UNLESS he has a buyer who is seriously looking for a home and wants to tour on Sunday, in which case, the agent had better be out there with that buyer or the buyer could go in an open house and buy it without you.

Sunday is best, IMO, because the consumer is focused on Opens on Sunday.

Time of year is an issue as well. For us in Tallahassee, College Football shuts Saturdays down as a traffic day.

We do them on Thursday evenings from 5-7:30PM and works better than Weekends for us in Jacksonville, Fl area. We also have different signs not the red and white that everyone uses and they all blend in and no one sees them anymore. Make it Different, Be Different and STAND OUT and Above! Good Luck

This is pretty interesting.  First of all its interesting that people find alot of people coming later at 4-6.   I have all seen traffic come in at that time but never talked to other realtors that stayed later.  So its interesting that other people see the same thing.  Its also interesting people are doing them on the weekday.  I have not tried that yet but that is pretty intriguing.