We were on the sailing last week with the fog delay. I had booked our flights for 5:35pm out of IAH and my DH had been giving me a hard time about how late I booked it (he hates hanging out in the airport, where as I like to be there early & relax). Well with the fog delay we missed the 5:35 flight. On the bus at 4, at the airport at 6, on a the plane for 7:30 flight.
If we were going again, I would still book the 5:35 flight as I think our fog delay was extreme, but there could be delays docking & traffic can be heavy.