Я ни разу не ездил на юг зимой.

This is normal in Russian. Russian often uses negative concord, where multiple negative words appear together in the same sentence.

• не ездил = did not go / did not travel
• ни разу = not even once

So Я ни разу не ездил... literally feels like:

• I not-even-once did not travel...

but in natural English it means:

• I have never traveled...
• I have not gone even once...

In Russian, ни разу normally goes with a negative verb:

• Я ни разу не был в Москве.
• Он ни разу не звонил.

You generally would not say Я ни разу ездил... without не.

Ни разу means not once, never even once, or not a single time.

It emphasizes that something has never happened at all.

So:

• Я ни разу не ездил на юг зимой = I have never gone/traveled south in winter, not even once

Compare:

• Я не ездил на юг зимой = I didn’t go south in winter
  This could refer to one situation or one period.
• Я ни разу не ездил на юг зимой = I have never gone south in winter
  This strongly means zero times in my life / experience.

This is a very common Russian question.

Russian has two related verbs:

• ехать = to go by transport in one specific direction, one concrete trip
• ездить = to go by transport repeatedly, generally, or at least without focusing on one single one-way trip

Here, ездил is the past tense of ездить.

Why is ездил used here? Because the sentence is about life experience: whether the speaker has ever done this before. Russian usually uses ездить for that kind of statement.

So:

• Я ни разу не ездил на юг зимой = I have never traveled to the south in winter

If you used ехал, it would sound like a specific trip in progress or a concrete one-time movement, which does not fit ни разу well.

A useful pattern:

• Я был в Париже = I have been to Paris
• Я ездил в Париж = I went/traveled to Paris
• Я ни разу не ездил в Париж = I have never gone/traveled to Paris

In the past tense, Russian verbs agree with the subject’s gender if the subject is singular.

• Я ездил = said by a man
• Я ездила = said by a woman

So the sentence as written is spoken by a male speaker:

• Я ни разу не ездил на юг зимой.

If a woman says it, it becomes:

• Я ни разу не ездила на юг зимой.

This happens with many past-tense verbs:

• Я был / Я была
• Я читал / Я читала
• Я работал / Я работала

Russian uses на + accusative in the fixed expression meaning to the south / southward.

So:

• на юг = to the south
• на север = to the north
• на запад = to the west
• на восток = to the east

This is the normal pattern for movement in a direction.

Examples:

• Мы поехали на юг. = We went south.
• Птицы летят на юг. = Birds fly south.

Using в юг would be incorrect here.

Here юг is in the accusative case because it follows на in a motion/direction meaning.

• на юг = toward the south / to the south

For masculine inanimate nouns like юг, the accusative looks the same as the nominative, so the form stays юг.

Compare:

• на юг = to the south, southward
• на юге = in the south

So:

• Я ездил на юг. = I traveled south.
• Я был на юге. = I was in the south.

That is an important distinction:

• movement toward something → often accusative
• location at/in something → often prepositional

Russian often uses the instrumental case by itself to express time, especially with seasons and parts of the day.

So:

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

That is why there is no в here.

So:

• Я ни разу не ездил на юг зимой = I have never gone south in winter

This is a very common pattern.

You can compare:

• утром = in the morning
• днём = in the daytime
• вечером = in the evening
• ночью = at night

Yes, you could, and it would be correct.

But there is a nuance:

• никогда не = never
• ни разу не = not even once

Both can often be translated as never, but ни разу не stresses the idea of zero occasions more strongly.

So:

• Я никогда не ездил на юг зимой = I never traveled south in winter
• Я ни разу не ездил на юг зимой = I have not traveled south in winter even once

In many contexts they are very close, but ни разу feels a little more emphatic about the number of times.

Normally, Я ни разу не ездил на юг зимой suggests life experience up to now: the speaker has never done this.

Because of ни разу не, the meaning is broader than just one specific winter.

It usually means something like:

• I have never gone south in winter
• There has not been a single occasion when I traveled south in winter

If you wanted to talk about one specific winter, Russian would usually make that clearer with context, for example:

• Той зимой я не ездил на юг. = That winter I didn’t go south.

Yes. Russian word order is flexible, and changing it often changes emphasis, not the basic meaning.

The original sentence:

• Я ни разу не ездил на юг зимой.

Other possible orders:

• Я зимой ни разу не ездил на юг.
• На юг зимой я ни разу не ездил.
• Ни разу я не ездил на юг зимой.

All of these can be correct in the right context.

Very roughly:

• зимой earlier in the sentence can emphasize in winter
• на юг earlier can emphasize to the south
• ни разу earlier can emphasize not even once

But the neutral, natural sentence is the one you were given.

It can be translated in several ways depending on context:

• went
• traveled
• went by transport
• sometimes even visited in a broad sense

The Russian verb ездить usually implies travel by some form of transport, not necessarily on foot.

So this sentence could be understood as:

• I have never gone south in winter
• I have never traveled to the south in winter

In many learning contexts, traveled is a helpful translation because it fits the general-experience meaning well.