That's unusual. They don't normally show until late winter, but they are fully hardy so it won't matter how cold it gets. I wonder if you bought the forced ones (for indoors) by mistake.

I wonder if they are actually indoor ones too... but as Bendipa says if they are outdoor ones they are fully hardy. We have lots of bulbs putting their noses above the ground already.

They were indoor hyacinths last year. I always keep my indoor ones to put in the garden the next autumn and they always flower the following spring. We'll wait and see.
I also have some crocus showing through. Thanks for replies.

My forced ones out in a dark shed are pushing themselve high up from the compost so I had to topdress, little shoots appearing too, its been mild recently maybe thats why