Сегодня в парке намного тише, чем вчера.

In Russian, the present-tense form of to be is usually omitted.

So:

• Сегодня в парке намного тише, чем вчера. literally looks like
• Today in the park much quieter than yesterday.

But in natural English, we say:

• Today it is much quieter in the park than yesterday.

Russian does not normally say есть here. Using есть in this kind of sentence would usually sound wrong or unnatural.

Тише is the comparative form of тихий.

• тихий = quiet
• тише = quieter

So намного тише means much quieter.

A useful thing to know is that Russian comparative forms like тише can often work in a very flexible way. In English, we distinguish between:

• quiet (adjective)
• quietly (adverb)

But in Russian, тише can cover the idea of quieter in a broader sense depending on context.

After намного in a comparison, Russian normally uses the comparative form, not the basic adjective or adverb.

So:

• намного тише = much quieter

Not:

• намного тихий ❌
• намного тихо ❌

This is similar to English: we say much quieter, not much quiet.

Намного means much, a lot, or significantly in comparisons.

So:

• намного тише = much quieter

Common alternatives include:

• гораздо тише = much quieter / far quieter
• значительно тише = significantly quieter

All of these intensify the comparison.

Чем is the usual word for than in comparisons.

So:

• тише, чем вчера = quieter than yesterday

This is one of the most common comparison patterns in Russian:

• лучше, чем... = better than...
• хуже, чем... = worse than...
• быстрее, чем... = faster than...

Because this sentence describes location, not movement.

• в парке = in the park
• в парк = into the park / to the park

Here, the idea is today, in the park, it is much quieter, so Russian uses the prepositional case after в:

• парк → в парке

If there were movement, then в парк would be correct:

• Я иду в парк. = I am going to the park.

Вчера is already an adverb meaning yesterday, so it does not need a preposition.

• сегодня = today
• вчера = yesterday
• завтра = tomorrow

So чем вчера simply means than yesterday.

Russian often uses these time words on their own:

• Сегодня холодно.
• Вчера было тепло.

No. Russian word order is flexible, and the sentence can be rearranged for emphasis.

For example:

• Сегодня в парке намного тише, чем вчера.
• В парке сегодня намного тише, чем вчера.

Both are natural.

The version with Сегодня first puts a little more focus on today. The version with В парке first puts a little more focus on in the park.

So the word order can change, but the basic meaning stays the same.

It usually means the situation or atmosphere in the park is quieter.

Russian often uses this kind of structure without explicitly saying it. So the sentence is not really describing the park as an object; it is describing the level of noise there.

A more literal way to think of it is:

• Today, in the park, things are much quieter than yesterday.

Yes. Тише! can be used by itself as an instruction:

• Тише! = Quiet! / Be quieter! / Keep it down!

But in your sentence, тише is not a command. It is part of a comparison:

• намного тише, чем вчера = much quieter than yesterday

So the same form can appear in different kinds of sentences, and context tells you which meaning is intended.