Is this correct?

A: ''This is the coldest winter I've ever known/seen." (personal experience)
''This is the coldest winter we've ever had." (talking about the location where you live)

B: "It's natural (that) winter should be as cold as this."
"that" is optional but I would personally include it. It makes the sentence easier to read.

I see. Thank you very much for you answer. It's interesting to know that the choice of verbs can make the sentence either personal or general.

teacherJapanI see. Thank you very much for you answer. It's interesting to know that the choice of verbs can make the sentence either personal or general.

The subjects are also different. I think this has more to do with making the sentence either personal or impersonal.

Persian LearnerThe subjects are also different. I think this has more to do with making the sentence either personal or impersonal.

Yes, indeed. In principle the choice of verb shouldn't make a difference to this, but for some reason the particular combination "This is the coldest winter I've ever had" does not seem very idiomatic to me, so I cha

GPY"This is the coldest winter I've ever had" does not seem very idiomatic to me, so I changed the verb.

Mark Twain liked another verb when he said: "The coldest winter I ever spent was a summer in San Francisco."

What about 'experienced?' This is the cold est summer I've ever experienced. Sounds natural enough?

Experienced is fine in that context.

~ Gingernut

Thank you!

The verb is fine, but there are a few minor adjustments for the remainder.

The coldest winter (I've / I have) ever spent, was a summer in San Francisco.

Adjustments are in bold.

~ Gingernut

teacherJapanA: ''This is the colder winter I've ever had. "

This is the coldest winter I have/ I've ever [seen/known/experienced].

Alternatively, This winter has been the coldest I have/ I've ever [...]

~ Gingernut