England in February

Yorkshire Dales are more likely to have snow than Cornwall and it is February.

You'd be unlucky to get much snow in Cornwall in Feb but do expect rain and/or gales.

I don't know about the York Dales but I'd expect many tourist attractions etc in Cornwall to be closed or have restricted opening in Feb as this is often when maintenance is done and, in any case, there are too few visitors to make opening viable. If you are driving bear in min that - even by British standards - roads in Cornwall are narrow and bendy and also, again even by British standards - the weather is very changeable. Always carry a waterproof even if the day seems like it will be dry.

Personally, I'd go somewhere with more indoor things to see as the weather in Feb anywhere in the UK can just be downright miserable. Given where you say you've been, I'd go to York; a beautiful city with lots to see (much of it indoors). You don't want a car in York itself (parking is v difficult) but on nice days you could look to hire a car or get public transport to villages etc nearby. Again check opening times of popular sights (such as Castle Howard).

In February, I would definitely pick Yorkshire over Cornwall. It will be much easier to get around, and there are plenty of quaint charming villages in the Dales for you to choose from. Grassington is a nice place to base yourself but there are many more.

I would say Cornwall. Like anywhere in the country (Yorkshire included) it could be gales and wet, but inherently Cornwall is likely to be a lot milder than anywhere in the north. There is a reason for the early Spring flowers in Cornwall- the mild climate.

I've been in Cornwall in January and February and it is bliss not finding everywhere clogged up with visitors cars, but most guest houses and hotels are open and at bargain rates.

This weekend has been a sharp reminder of how hard the winters can bite, and they can bite hard in the Yorkshire Dales- as anyone who saw the pictures of mountainous snow in Wensleydale can attest.
There was a snowplough train yesterday morning on the Settle Carlisle line which itself got stuck in the snow for a time apparently.

Mid February is still very much winter time up North, and I say that as someone who loves the Dales, and has very personal links with the Grassington area.

Cornwall is a safer bet for February weather wise and is very enjoyable out of season when you can park easily and get a table without pre booking. Obviously the weather could be terrible but it most likely to be wind and rain rather than snow and ice.

I would unquestionably pick York and surroundings.
We no longer get long long winters, snow is likely to be a fleeting visitor and you could pick the " good days" to travel.
York is very very good for train travel in all directions too.