kyou wa kinou yori motto samui desu.

It's even colder today than yesterday.

Breakdown of kyou wa kinou yori motto samui desu.

• は: topic particle
• です: to be
• 今きょ日う: today
• 寒さむい: cold
• 昨日きのう: yesterday
• より: comparative particle
• もっと: more

Questions & Answers about kyou wa kinou yori motto samui desu.

What function does は serve after 今日?

は is the topic marker. It tells the listener “we’re talking about 今日 (today).” Structurally:

• 今日は – “As for today…”
  Without は, you’d lose that “as for” nuance.

Why is there no particle after 昨日, but there is より attached to it?

より is a comparison particle meaning “than.” It attaches directly to the thing you’re comparing against (here 昨日). So:

• 昨日より – “than yesterday.”
  You don’t use は or が again because より already shows its role in the comparison.

What’s the role of もっと in this sentence? Could we drop it?

もっと means “more” (to intensify). It amplifies the adjective:

• 寒い – “cold”
• もっと寒い – “colder” (more cold)
  You can drop もっと and still be correct:
• 今日(は)昨日より寒いです。 – “Today is colder than yesterday.”
  But adding もっと makes the contrast stronger: “Today is even more cold compared to yesterday.”

Can you explain the comparative structure Aは Bより C です?

This is a standard pattern for comparisons:

1. A は – topic (thing being described)
2. B より – “than B” (comparison target)
3. C です – descriptive predicate (adjective or noun + polite です)
   Together: “As for A, it is C compared to B.”
   Example:
   
   • 東京は大阪より大きいです。
     (“Tokyo is bigger than Osaka.”)

Why is です used at the end? Can it be omitted or changed?

です is the polite copula, making the sentence polite.

• Without です: もっと寒い。 sounds casual/blunt, like speaking among close friends.
• You can change です to other forms:
  • でした (past): 今日(は)昨日よりもっと寒かったです。
  • Plain form: もっと寒い (no です)
  Politeness level and tense determine which you choose.

Why not use ほうが here (e.g. 今日のほうが昨日より寒いです)? Are they interchangeable?

You can indeed say:

• 今日のほうが昨日より寒いです。
  Both mean “Today is colder than yesterday,” but subtle differences exist:
• AはBよりC – straightforward comparison.
• AのほうがBよりC – emphasizes “A is the one that’s more C.” It often feels slightly more explicit.
  In daily speech they’re largely interchangeable.

Could we rearrange word order, like 昨日より今日はもっと寒いです?

Yes. Japanese is flexible with word order as long as particles stay with their words.

• 昨日より今日はもっと寒いです。
  This still means “Compared to yesterday, today is even colder.”
  Putting 今日は later can add emphasis on 今日 or just vary rhythm, but meaning remains the same.

Why is the adjective in its い-adjective form 寒い and not changed to something else?

寒い is already the plain form of the い-adjective “cold.” In a comparative you keep the adjective’s base form (＋です if polite). You only conjugate it for tense or politeness:

• Present polite: 寒いです
• Past polite: 寒かったです
• Plain present: 寒い
  So もっと寒いです is simply the polite present comparative.