Weather is the reason airlines give most often and the one passengers accept most readily, and the acceptance is usually premature. The retained UK Regulation does contain a defence for circumstances outside the airline's control, but it is a defence the airline has to make out, it has two limbs rather than one, and it removes only part of what a cancelled passenger is owed. Reading the sentence itself is the fastest way to see how much of the story the word weather actually covers.
The defence has two limbs and the airline must prove both
The Regulation says an operating air carrier shall not be obliged to pay compensation if it can prove that the cancellation is caused by extraordinary circumstances which could not have been avoided even if all reasonable measures had been taken. So it is not enough that a storm existed. The carrier must show the storm caused this cancellation, and that no reasonable measure would have avoided it. An airline that could have flown a spare aircraft, or re-routed a crew, or that cancelled a flight for a storm three legs earlier in the day, is being asked a question it has to answer with evidence rather than with a category.
What the defence does not touch, which is most of it
The defence is attached to the compensation article and to nothing else. The right to choose between a refund of the unused ticket and re-routing to your destination survives any weather. So does the right to care: meals and refreshments in reasonable relation to the waiting time, a hotel where an overnight stay becomes necessary, and transport between the airport and that hotel. Those obligations exist precisely because the passenger is stranded through no fault of anyone, and a passenger told that a storm means the airline owes them nothing has been told something the Regulation does not say.
Weather at your airport is not the only weather that matters
The cause the airline points to is often somewhere else: fog at the aircraft's previous destination, a de-icing queue at a hub, an air traffic control flow restriction imposed because of storms hundreds of miles away. Whether any of that is extraordinary in the Regulation's sense, and whether it could have been worked around, is exactly the kind of question an Alternative Dispute Resolution scheme exists to weigh. It is not a question the check-in desk decides, and a refusal at the desk is not the end of the matter.
In the United States the question does not arise
There is no US analogue to this argument, because there is no US payment for a cancellation or a delay for the defence to remove. A US passenger whose flight is cancelled for weather gets their fare back on the same terms as a passenger whose flight was cancelled for a crew shortage, and gets nothing further under the rules in either case. The airline's own Customer Service Plan is then the document that decides whether a hotel appears, and unlike the European care obligation that promise is contractual rather than statutory.
Questions people ask about flight cancelled due to weather compensation
Do flights cancelled due to weather ever carry compensation?
They can, where the airline cannot make out both limbs of the defence: that the circumstance was extraordinary, and that it could not have been avoided even if all reasonable measures had been taken. It is a question of evidence rather than of category.
The airline sent a message saying weather, so is that decided?
No. A message is the airline's assertion of a defence, not proof of it. If you disagree, the free next step is the airline's ADR scheme or, where it belongs to none, the Civil Aviation Authority's own complaints route.
Do I still get a hotel if it was weather?
Under the retained UK Regulation the right to care is not affected by the reason for the disruption. It is the one part of the scheme that is deliberately blind to fault.
How long do I have to bring a claim?
The Regulation itself sets no limitation period; the time limit comes from the ordinary law of the country where you claim, and it is measured in years rather than months in the United Kingdom. That is worth knowing before assuming an old disruption is out of time.