Zimą moja skóra jest sucha, dlatego piję więcej wody.

Zimą is the instrumental case of zima (winter).

In Polish, seasons can be used in the instrumental case to mean during that season:

• zimą = in winter
• latem = in summer
• jesienią = in autumn
• wiosną = in spring

So Zimą moja skóra jest sucha means In winter, my skin is dry.

You may also hear w zimie, which also means in winter, but zimą is a very common and natural way to say it.

Because Polish often uses the instrumental case by itself for time expressions like seasons.

So instead of saying literally in winter with a preposition, Polish can simply say:

• zimą = in winter
• rano = in the morning
• wieczorem = in the evening

This is just a normal Polish pattern. You do not need w before zimą here.

Because skóra is a feminine noun, and the possessive adjective my must agree with it.

So:

• mój = my (masculine)
• moja = my (feminine)
• moje = my (neuter)

Since skóra is feminine, we say:

• moja skóra = my skin

Because adjectives in Polish must agree with the noun they describe.

Since skóra is feminine, the adjective must also be feminine:

• suchy = dry (masculine)
• sucha = dry (feminine)
• suche = dry (neuter)

So:

• sucha skóra = dry skin
• moja skóra jest sucha = my skin is dry

In this sentence, jest means is and is the normal verb to be.

• moja skóra jest sucha = my skin is dry

In the present tense, Polish usually does use forms of być (to be) in sentences like this.

So unlike in Russian, for example, you generally should not omit it here.
Moja skóra sucha would sound incomplete or unnatural in standard Polish.

Dlatego means therefore, that’s why, or for that reason.

It connects the two parts of the sentence:

• Zimą moja skóra jest sucha, dlatego piję więcej wody.
• In winter my skin is dry, therefore / that’s why I drink more water.

It is a very common word for showing cause and result.

Because dlatego is connecting two clauses, and in Polish this kind of connection is normally separated by a comma.

So the structure is:

• clause 1: Zimą moja skóra jest sucha
• clause 2: dlatego piję więcej wody

That is why the comma is natural here.

Piję is the 1st person singular form of pić (to drink), so it means I drink.

The present tense forms are:

• ja piję = I drink
• ty pijesz = you drink
• on/ona/ono pije = he/she/it drinks
• my pijemy = we drink
• wy pijecie = you drink
• oni/one piją = they drink

So:

• piję = I drink
• pije would be incorrect here; the correct 3rd person form is pije

Also notice the final ę, which is a nasal vowel.

Because after więcej (more), Polish normally uses the genitive case.

• basic noun: woda
• genitive singular: wody

So:

• piję wodę = I drink water
• piję więcej wody = I drink more water

This is a very important pattern:

• dużo wody = a lot of water
• mało czasu = little time
• więcej kawy = more coffee

Because water here is treated as an uncountable substance, just like in English.

So Polish uses the singular noun:

• woda = water
• więcej wody = more water

You are not talking about separate countable units like bottles or glasses, just the substance itself.

Yes, Polish word order is fairly flexible, though some orders sound more natural than others.

The original sentence is very natural:

• Zimą moja skóra jest sucha, dlatego piję więcej wody.

You could also say:

• Moja skóra zimą jest sucha, dlatego piję więcej wody.
• Dlatego piję więcej wody, bo zimą moja skóra jest sucha.

The meaning stays similar, but the emphasis changes a little.
Putting Zimą first highlights the time frame right away.

Skóra is pronounced approximately SKOO-ra, with stress on the first syllable:

• skó- sounds roughly like skoo
• -ra is a short final syllable

A few useful pronunciation notes:

• ó is pronounced like u
• Polish stress is usually on the second-to-last syllable, so SKÓ-ra

Piję is pronounced approximately PEE-yeh or PEE-ye, with a nasal ending that is often weakened in normal speech.

A few points:

• pi- sounds like pee
• j sounds like English y
• ę is a nasal vowel, but at the end of a word it is often pronounced less strongly than learners expect

So piję may sound something like:

• PIE-yeh
• or lightly nasalized PIE-ye

The spelling still matters even if the full nasal quality is not always strongly heard.

Yes. Sucha skóra is a very normal and common way to say dry skin.

You can use it both:

• as a noun phrase: sucha skóra
• in a full sentence: moja skóra jest sucha

So this sentence sounds natural and idiomatic in Polish.