The delay on the BA service to Rome from Terminal 5 was only a couple of hours (something to do with the weather, though, to my eyes, the sky was cloudless and the sun shining).
May as well stop reading at that point.
I recollect, when flying the Highlands & Islands services in Viscounts, that we had few complaints from passengers re weather engendered delays. Most of them were, were related to or knew crofters, farmers or fishermen and were familiar with the limitations which weather can place upon operations.