Zimą krem i balsam stoją u mnie na półce w łazience.

Zimą is the instrumental singular of zima and is commonly used as an adverb meaning in winter.

Polish often does this with the seasons:

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

So Zimą at the start of the sentence sets the time frame: in winter.

Yes, w zimie is also possible and means basically the same thing: in winter.

However, zimą is very common and compact, and many learners hear it more often in everyday speech. In this sentence, zimą sounds very natural.

In Polish, it is very common to describe the physical position of objects:

• stoi / stoją = stands / are standing
• leży / leżą = lies / are lying
• wisi / wiszą = hangs / are hanging

So krem i balsam stoją na półce suggests that the containers are standing upright on the shelf.

You could say są na półce, and it would mean are on the shelf, but stoją is more specific and often more natural for bottles, tubes, or containers placed upright.

Because the subject is two things together: krem i balsam.

Even though krem is singular and balsam is singular, together they form a plural subject, so the verb must also be plural:

• krem stoi = the cream is standing
• balsam stoi = the lotion/balm is standing
• krem i balsam stoją = the cream and the lotion/balm are standing

U mnie literally means something like at me, but in natural English it usually means:

• at my place
• where I live
• in my home
• sometimes simply with me

In this sentence, u mnie means at my place / in my home. So na półce w łazience is happening in the speaker’s bathroom at home.

Because u mnie is a very natural, idiomatic way to say at my place without sounding too heavy.

Compare:

• u mnie = at my place
• w moim domu = in my house
• w mojej łazience = in my bathroom

The sentence already has w łazience, so u mnie adds the idea that this bathroom is at the speaker’s place. It sounds natural and conversational.

Both are in the locative case because they describe location, not movement.

• na półce = on the shelf
• w łazience = in the bathroom

Here is the logic:

• na + locative = on something, when there is no movement
• w + locative = in something, when there is no movement

So:

• półka → na półce
• łazienka → w łazience

If there were movement, the forms would change:

• na półkę = onto the shelf
• do łazienki = into the bathroom

In Polish, balsam can mean several related cosmetic products, depending on context. Very often it means:

• body lotion
• balm
• sometimes another kind of skincare product

So in a sentence like this, balsam is often best understood as lotion rather than a small medicinal balm. The exact English translation depends on what product the speaker has in mind.

Because Polish does not have articles like a or the.

So krem i balsam can mean:

• the cream and the lotion
• a cream and a lotion
• sometimes just cream and lotion

The exact meaning depends on context. In most real situations, the listener already knows which cream and lotion are being talked about.

Yes. Polish word order is fairly flexible, because endings show grammatical relationships.

This version:

• Zimą krem i balsam stoją u mnie na półce w łazience.

is natural and starts by emphasizing when: in winter.

Other word orders are possible, for example:

• U mnie krem i balsam stoją zimą na półce w łazience.
• Na półce w łazience stoją u mnie zimą krem i balsam.

These are not all equally neutral, though. The original sentence sounds like a normal, natural way to present the information.

By itself, zimą usually gives a general seasonal frame: in winter.

Depending on context, it can mean:

• in winter, generally
• during the winter season
• sometimes this winter, if the context makes that clear

So the sentence could mean something like In winter, I keep the cream and lotion on the bathroom shelf or simply describe a winter arrangement at the speaker’s home. Context decides how specific it is.