No not dangerous but some insurance companies may have an issue with it.
Next time around get the new Michelin cross climate tyres, very good for all scenarios.
The winter tyres won't run out that quickly if used in hotter weather. They performance is the main issue, they won't grip well in comparison to a summer tyre. It's like using a summer tyre in the winter, they don't work well.
I'm only thinking for a couple weeks while my wheels are being refurbished. Seems like it would be OK maybe they are on a v speed rating so surely they would be OK on the motorway wouldn't they?
Winter tyres in summer are fine, provided the tyres are rated correctly for your car there is no problem.
As for winter tyres wearing quicker at higher temperatures, I don't think that is correct. The thing with winter tyre compounds is, they don't go hard at lower temperatures but that doesn't mean they go soft at higher temperatures.
If only that were true.
Tyre manufacturers could switch to the magic compound for their summer tyres, instantly turning them into all season tyres with fantastic grip and wear rates in all conditions and motorsport teams would no longer need to pick a tyre compound appropriate for the track temperature.