Зимой я ношу тёплый шарф и варежки.

Зимой is the instrumental singular of зима (winter), but here it is being used adverbially to mean in winter / during winter.

This is very common with seasons in Russian:

• зимой — in winter
• весной — in spring
• летом — in summer
• осенью — in autumn

So Russian often says simply зимой, without a preposition, where English uses in.

You can leave it out.

Russian often drops subject pronouns when they are clear from the verb ending.
Ношу already means I wear / I carry, so:

• Зимой я ношу тёплый шарф и варежки.
• Зимой ношу тёплый шарф и варежки.

Both are natural.

Including я can make the subject a little clearer or more emphatic, especially if you are contrasting yourself with someone else.

Because носить means to wear in the sense of wearing something regularly, habitually, or over a period of time.

This sentence describes a general habit in winter, so ношу is the right choice.

Compare:

• Зимой я ношу шарф. — In winter I wear a scarf.
• Я надеваю шарф. — I am putting on a scarf.

So:

• носить = to wear
• надеть / надевать = to put on

A useful distinction is:

• Что ты носишь зимой? — What do you wear in winter?
• Что ты сейчас надеваешь? — What are you putting on now?

Yes. Носить can mean both to carry and to wear, depending on context.

For example:

• носить сумку — to carry a bag
• носить шарф — to wear a scarf

This is normal in Russian. The context tells you which meaning is intended.

Because the adjective must agree with the noun it modifies in gender, number, and case.

Here, шарф is:

• masculine
• singular
• accusative (because it is the direct object of ношу)

But for masculine inanimate nouns, the accusative looks the same as the nominative. So:

• nominative: тёплый шарф
• accusative: тёплый шарф

That is why you see тёплый, not тёплого or тёплую.

Because шарф is an inanimate masculine noun, and in Russian the accusative singular of inanimate masculine nouns is usually identical to the nominative singular.

So:

• nominative: шарф
• accusative: шарф

That is why the noun looks unchanged.

Compare that with an animate masculine noun:

• Я вижу брат — incorrect
• Я вижу брата — correct

For animate masculine nouns, the accusative usually matches the genitive. But шарф is inanimate, so there is no change.

Yes, the singular is варежка.

In this sentence, the plural варежки is used because mittens are normally thought of as a pair, just like in English we often say mittens rather than a mitten.

Also, since варежки is an inanimate plural direct object, its accusative form is the same as its nominative form:

• nominative plural: варежки
• accusative plural: варежки

Strictly speaking, тёплый directly modifies only шарф.

So the sentence literally has the structure:

• a warm scarf and mittens

If you want to make it clear that both are warm, Russian usually repeats the adjective:

• Зимой я ношу тёплый шарф и тёплые варежки.

That is the clearest and most natural way.

Yes. Russian word order is more flexible than English word order because the grammar is shown partly by endings, not just position.

The sentence as given:

• Зимой я ношу тёплый шарф и варежки.

is very natural and neutral, with зимой setting the time first.

Other possible orders include:

• Я зимой ношу тёплый шарф и варежки.
• Тёплый шарф и варежки я ношу зимой.

These are all grammatical, but they shift emphasis slightly.

A rough idea:

• Зимой... — focuses first on the time
• Я... — focuses more on the speaker
• Тёплый шарф и варежки... — focuses more on the things worn

The main stresses are:

• зимОй
• ношУ
• тЁплый
• шарф
• варЕжки

A useful note: ё is always stressed, so тёплый must be pronounced with stress on тё.

Yes. In real Russian texts, ё is often written as е, so you may see:

• тёплый
• теплый

These represent the same word, but the pronunciation is still тёплый, not теплый.

For learners, dictionaries and textbooks often write ё to make pronunciation clearer.

Not exactly. Варежки means mittens, not gloves.

A mitten has one section for the thumb and one section for the other fingers together.

Russian distinguishes:

• варежки — mittens
• перчатки — gloves

So it is good to learn this vocabulary difference early.

No, not in normal Russian.

For the general meaning in winter, the natural form is зимой.

• Зимой я ношу тёплый шарф и варежки. — correct

В зиме does not normally mean in winter in this kind of sentence. It would sound unnatural here.

So for seasons, it is best to remember these as set adverbial forms:

• зимой
• весной
• летом
• осенью