Вчера вечером я простудился в парке.

Вечером here is the instrumental case of вечер used as an adverbial expression of time, meaning “in the evening”.

Russian often uses bare instrumental (no preposition) to say “in/at (time of day)”:

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

Adding в (в вечером) is ungrammatical in this usage. You simply say вчера вечером = “yesterday evening.”

The base (dictionary) form is вечер – “evening” (masculine noun).

In вчера вечером, вечером is:

• Case: instrumental singular
• Function: adverbial modifier of time (“in the evening”)

So you have:

• вечер – nominative (the evening)
• вечером – instrumental (“by/in the evening” → “in the evening” as a time phrase)

Yes, that word order is natural. All of these are grammatically correct, with slight differences in emphasis:

• Вчера вечером я простудился в парке.
  Neutral: setting the time first (“Yesterday evening I caught a cold in the park”).

• Я вчера вечером простудился в парке.
  Slightly more focus on я (I), then time, then place.

• Я простудился вчера вечером в парке.
  Focus more on the event простудился followed by its circumstances.

• В парке я вчера вечером простудился.
  Emphasis on в парке – “It was in the park that I got sick yesterday evening.”

Russian word order is flexible; time and place adverbials can move around, mainly affecting nuance and emphasis rather than basic meaning.

Простудился can be broken down as:

• простудил- – past tense masculine stem of the verb простудиться
• -ся → becomes -сь after a vowel, but here you see it inside -лся
• -лся = -л (past tense) + -ся (reflexive pronoun clitic) joined together

So простудился tells you:

1. Past tense
2. Masculine singular
3. Reflexive (the action is on the subject himself)

Compare:

• я простудился – I (male) caught a cold
• я простудилась – I (female) caught a cold
• мы простудились – we caught a cold

Russian often uses reflexive verbs for:

• actions affecting the subject themself
• changes of state or condition

Простудиться literally means something like “to make oneself cold / to become cold-ill,” i.e., to catch a cold.

If you remove -ся and say простудил, you need a direct object:

• Я простудил ребёнка. – I made the child catch a cold / I gave the child a chill.

So:

• я простудился – I caught a cold (myself)
• я простудил ребёнка – I caused the child to catch a cold

Using the reflexive form is the normal, idiomatic way to say “caught a cold” about yourself.

The infinitive is простудиться.

• Aspect: perfective
• Meaning: to catch a cold (as a single, completed event)

In contrast, the imperfective partner is простужаться:

• я простужался в детстве – I used to catch colds in childhood (repeated/habitual).

In your sentence, простудился (perfective) presents the catching of the cold as one completed event yesterday evening.

You could, but it would mean something different and sound odd in this context.

• я простудился в парке – I caught a cold in the park (one specific event, completed).
• я простужался в парке – I was catching colds in the park / I used to catch colds in the park (process, repeated or habitual).

Since we’re talking about a single event “yesterday evening”, the perfective простудился is the natural choice. Простужался would suggest either a longer process (“was in the process of getting sick”) or something habitual.

В парке uses:

• в
  • prepositional case = location “in the park”
• Nominative: парк
• Prepositional: в парке

Compare:

• Я иду в парк. – I am going to the park (direction → accusative after в)
• Я в парке. – I am in the park (location → prepositional after в)

На парке is incorrect here because на is not used with парк for normal “in the park” meaning. You say:

• в парке – in the park
• на пляже – on the beach
• на стадионе – at the stadium

Choice of в vs на is largely idiomatic and must be memorized with each noun.

Парке is the prepositional singular of парк (a masculine noun).

Declension (singular):

• Nominative: парк (the park)
• Genitive: парка
• Dative: парку
• Accusative: парк
• Instrumental: парком
• Prepositional: (о) парке

With the preposition в for location, you use the prepositional:

• в парке – in the park

Yes, grammatically you can say:

• Вчера вечером простудился в парке.

The verb ending -лся already shows masculine singular, so the subject is recoverable from context.

However:

• In neutral, clear speech or writing, Russians often keep я: Я простудился.
• Dropping я sounds more colloquial or “diary style,” or assumes the listener already knows you’re talking about yourself.

So it’s possible, but Вчера вечером я простудился в парке is the most standard, explicit version.

Spelling: простудился
Pronunciation (approx.): pras-tu-DI-lsya

There are two key points:

1. The д before и is soft: д
   • и → [dʲi].
2. In -лся, the л and с are both pronounced: [lsʲa].

So you do pronounce the д clearly:
про-сту-ДИ-лся (not просу or простуилса).

Rough syllable breakdown:

• про – [pra]
• сту – [stu]
• ди – [dʲi]
• лся – [lsʲa]

Main stresses:

• вчера́ – stress on -ра́
• ве́чером – stress on ве́-
• простуди́лся – stress on -ди́-
• па́рке – stress on па́-

So you get:

• вчера́ ве́чером я простуди́лся в па́рке.

Yes, a few common alternatives (for a male speaker):

1. Я простыл.

   • Also “I caught a cold / I’ve got chilled.”
   • Slightly shorter, more colloquial.

2. Я заболел.

   • “I got sick,” more general, not necessarily a cold.

3. Я кажется простудился.

   • “I think I caught a cold.”

But я простудился is the most direct and standard way to say “I caught a cold.”