Whens the last time you didnt go because of weather???
The last time that the destination and all the available alternates were TAFing below minimums for our arrival time, not actually that unusual on parts of our our route network in winter.
Quite agree with the comment about rules over common sense, it is only a prediction of what will happen and those predictions are often wrong. Whatever the rules might say about which bit of a forecast you can disregard you had better be careful heading for an area where the weather is filthy, and the forecasting not that great.