kotosi no huyu ha reinen yori samui desu.

の links two nouns together.

• 今年 = this year
• 冬 = winter
• 今年の冬 = this year's winter / the winter of this year

In English, we often use 's or of. Japanese uses の very often for that kind of connection.

は marks the topic of the sentence.

So 今年の冬は means something like:

• As for this winter...
• Speaking of this year's winter...

The rest of the sentence then says something about that topic: it is colder than usual.

より means than in comparisons.

• 例年 = usual years / an average year / every year in the normal sense
• 例年より = than usual / than in most years

So the sentence is comparing this winter with the typical winter.

Japanese usually does not need a separate word like more in this kind of comparison.

The pattern is:

• A は B より adjective
• A is more adjective than B

So:

• 今年の冬は例年より寒いです。
• literally: This year's winter, compared with usual years, is cold
• natural English: This winter is colder than usual.

The comparison is understood from より.

Both are correct, but they have different levels of politeness.

• 寒い = plain style
• 寒いです = polite style

Because 寒い is an い-adjective, it can already end a sentence by itself. Adding です makes it polite.

So:

• 今年の冬は例年より寒い。 = plain
• 今年の冬は例年より寒いです。 = polite

Yes, 寒いです is completely normal.

It is true that です is used after nouns and な-adjectives, but it can also follow い-adjectives to make the sentence polite.

Examples:

• 高いです = it is expensive/high
• 面白いです = it is interesting
• 寒いです = it is cold

So in this sentence, 寒いです is perfectly natural.

No, they are different.

• 例年 = usual years / average years / what normally happens every year
• 去年 = last year

So this sentence does not mean colder than last year.
It means colder than a typical year or colder than usual.

If you wanted colder than last year, you would say:

• 今年の冬は去年より寒いです。

Usually は is the most natural choice here because the sentence is presenting this winter as the topic.

• 今年の冬は例年より寒いです。 = As for this winter, it is colder than usual.

Using が is possible in some contexts, but it would sound more like you are specifically identifying this winter as the thing that is colder, often in contrast with something else or as new information.

For a basic neutral statement, は is best.

Yes, it is natural.

A normal written form would usually be:

• 今年の冬は例年より寒いです。

without spaces.

The version with spaces is just for learners, to make the parts easier to see.

Japanese is normally written without spaces between words.

So a native-style version is:

• 今年の冬は例年より寒いです。

Learner materials often insert spaces to help you notice word boundaries:

• 今年　の　冬　は　例年　より　寒い　です。

Both represent the same sentence, but the spaced version is mainly for study.

Yes. A common alternative is:

• 今年の冬は例年に比べて寒いです。

Here, に比べて also means compared with.

Nuance:

• 例年より寒いです = straightforward colder than usual
• 例年に比べて寒いです = compared to usual years, it is cold

Both are natural, but より is shorter and very common.

They are similar, but not identical in tone.

• 今年の冬 = this year's winter; very ordinary and conversational
• 今冬 = this winter; more formal, often seen in news reports, writing, or announcements

For everyday learning and conversation, 今年の冬 is easier and more common.