I have 1 1.5 m Gibertini here in Aalborg and I normally have reception 24/7 also in bad weather unless its *really* bad.
1.8 or larger in Copenhagen sounds about right, but be careful. Your 1.5 m is precision-cut at the factory. All the 1.8m+ dishes I've seen come in "petals" which need to be assembled. Most people claim that you'll lose a significant part of the signal since it's difficult to assemble petal dishes perfectly. Maybe a 2.1 m would be a better option.
I actually need to make some fine adjustments to my dish after the storm the other day O-st , but we're getting another small storm tonight so it'll have to wait a bit.
I got off light, a friend of mine's dish got turned into a calzone by the wind. O-Ha