Парковочная сессия закончилась в полдень.

Because the subject is сессия, and сессия is a feminine noun.

In the past tense, Russian verbs agree with the subject in gender and number:

• masculine: закончился
• feminine: закончилась
• neuter: закончилось
• plural: закончились

So Парковочная сессия закончилась literally shows that the session ended, with the verb matching the feminine noun сессия.

It is in the nominative case, because it is the subject of the sentence.

• парковочная = adjective, feminine singular nominative
• сессия = noun, feminine singular nominative

They agree with each other in gender, number, and case.

So the structure is:

• Парковочная сессия = the parking session
• закончилась = ended
• в полдень = at noon

Парковочная is an adjective meaning parking-related or for parking.

It comes from парковка meaning parking. In this sentence, парковочная сессия means something like:

• parking session
• paid parking session
• the period of active parking in a parking system/app

This is fairly administrative or app-style language. In everyday speech, Russians might sometimes use simpler alternatives depending on context.

Yes, but it sounds somewhat official, technical, or like the wording used in a parking app, website, or payment system.

A native speaker would understand it easily. In less formal speech, people might also say things like:

• парковка закончилась = the parking expired / ended
• время парковки закончилось = the parking time has ended

So парковочная сессия is natural, but it belongs especially to service/payment/transport language.

Закончилась is the perfective past form of закончиться, so it presents the action as a completed event: the session came to an end.

That makes sense here, because the sentence is about the fact that it ended.

Compare:

• закончилась = ended, came to an end
• заканчивалась = was ending, used to end, was coming to an end
• кончилась = also means ended, but can sound a bit more colloquial depending on context

So закончилась is a very standard and neutral choice.

Here в полдень uses the accusative case to express a point in time: at noon.

The preposition в often takes the accusative for time expressions like:

• в час = at one o’clock
• в пять часов = at five o’clock
• в понедельник = on Monday
• в полдень = at noon

With полдень, the accusative singular looks the same as the nominative singular, because it is an inanimate masculine noun:

• nominative: полдень
• accusative: полдень

So the form does not change, even though the case does.

В полдень is the normal idiomatic way to say at noon.

You can also say в двенадцать часов or just в двенадцать if you mean at twelve, but that is slightly different in feel:

• в полдень = at noon
• в двенадцать = at twelve

Usually they refer to the same time, but полдень specifically means midday/noon, not just the number twelve in some abstract sense.

На полдень would not work here for this meaning.

Because Russian does not have articles like a or the.

So Парковочная сессия can mean:

• a parking session
• the parking session

The exact meaning depends on context.

In this sentence, English would probably translate it as The parking session ended at noon, but Russian does not need a separate word for the.

Yes. Russian word order is flexible, because case endings show grammatical roles.

The neutral order here is:

• Парковочная сессия закончилась в полдень.

But other orders are possible, for example:

• В полдень парковочная сессия закончилась.
• Закончилась парковочная сессия в полдень.

These alternatives may shift emphasis:

• starting with в полдень highlights the time
• starting with закончилась can sound more narrative or emphatic

The original sentence is a straightforward, neutral way to say it.

The main stresses are:

• парко́вочная
• се́ссия
• зако́нчилась
• по́лдень

A rough pronunciation guide:

• par-KO-va-chna-ya
• SESS-ee-ya
• za-KON-chi-las'
• POL-den'

A few useful notes:

• чн in парковочная is pronounced like chn
• сессия has a soft с sound and two s letters in spelling
• the final -сь in закончилась is soft
• день in полдень has a soft н sound at the end

You could, but it would sound less natural in most everyday contexts.

• Парковочная сессия закончилась в полдень = the parking session ended at noon
• Парковочная сессия была закончена в полдень = the parking session was finished at noon

The second version is more passive and can suggest that someone or something actively finished it. The first version is much more natural for simply stating that the session came to an end.

So for most situations, закончилась is the better choice.