В июне дни длиннее, и вечером мне легче гулять после работы.

Because Russian uses в + prepositional case for months when you mean in a month.

• июнь = nominative form, the basic dictionary form
• в июне = in June

This is the normal pattern:

• в январе = in January
• в мае = in May
• в июне = in June

So в июне is not a different word you memorize separately; it is the prepositional-case form of июнь after в.

Because the sentence is making a general statement about the days in June as a whole: days are longer.

• день = day
• дни = days

So:

• В июне день длиннее would sound like In June, the day is longer, which can work in some contexts but is less natural here.
• В июне дни длиннее means In June, days are longer, which is the more natural general statement.

Because длиннее is the comparative form: longer.

• длинные = long
• длиннее = longer

So:

• дни длинные = the days are long
• дни длиннее = the days are longer

A very important point: Russian comparative forms like длиннее usually do not change for gender, number, or case. They stay the same.

• день длиннее
• дни длиннее
• ночь длиннее

This is different from normal adjectives like длинный / длинная / длинные.

Because in the present tense, Russian usually omits the verb to be.

So English:

• Days are longer

becomes Russian:

• Дни длиннее

There is no present-tense есть here. Using есть in this kind of sentence would sound unnatural.

This is very common in Russian:

• Он дома = He is at home
• Она занята = She is busy
• Дни длиннее = Days are longer

Because вечером is a very common adverbial use of the instrumental case meaning in the evening.

This pattern is common with parts of the day:

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

So вечером works almost like an adverb.

You can also say по вечерам if you mean in the evenings, regularly, but вечером here is the natural simple choice.

Because Russian often uses the dative case for the person who experiences a feeling, condition, or level of difficulty.

So:

• мне легче = it is easier for me
• literally: to me, easier

But:

• я легче means I am lighter in weight or physical lightness

That is a completely different idea.

This dative pattern is very common:

• мне трудно = it is hard for me
• ему легко = it is easy for him
• нам холодно = we are cold / it is cold to us
• ей нельзя = she is not allowed / it is not allowed for her

Легче is the comparative form related to лёгкий or легко, and here it means easier.

In this sentence, it is functioning as a predicative word: it describes how easy or difficult an action is.

• легко = easy / easily
• легче = easier

So:

• мне легко гулять = it is easy for me to walk
• мне легче гулять = it is easier for me to walk

This use is very common with infinitives:

• Мне трудно понять = It is hard for me to understand
• Ей проще сказать = It is easier for her to say
• Нам легче работать утром = It is easier for us to work in the morning

Because after words like легко, легче, трудно, можно, нельзя, Russian often uses an infinitive to name the action.

So:

• мне легче гулять = it is easier for me to walk / to go for a walk

The infinitive answers the question: easier to do what?

Compare:

• Мне легко читать. = It is easy for me to read.
• Ему трудно вставать рано. = It is hard for him to get up early.
• Нам нельзя шуметь. = We must not make noise.

Using a finite verb here would require a different structure.

Not exactly. Гулять often means to walk, stroll, go out, spend time outdoors, often for pleasure rather than for transportation.

So in this sentence, гулять после работы is closer to:

• go for a walk after work
• take a walk after work
• be out walking after work

If the idea were simply moving from one place to another on foot, Russian might use идти or ходить instead, depending on context.

So гулять gives the sentence a more relaxed, leisure meaning.

Because после requires the genitive case.

• работа = nominative
• работы = genitive

So:

• после работы = after work

This is a standard rule:

• после урока = after the lesson
• после обеда = after lunch
• после фильма = after the film
• после работы = after work

In normal everyday Russian, после работы usually means after work or after the workday / after finishing work.

It does not usually need extra words. Russian often leaves that idea implicit.

So гулять после работы naturally means something like:

• go for a walk after work
• take a walk when work is over

Yes, Russian word order is flexible. The given order is natural and clear.

Here is what the order does:

• В июне sets the time frame first
• дни длиннее gives the first statement
• вечером shifts to a more specific time of day
• мне легче presents the speaker’s experience
• гулять после работы names the action

Other orders are possible, for example:

• В июне дни длиннее, и мне легче гулять вечером после работы.
• В июне дни длиннее, и после работы мне легче гулять вечером.

These may sound slightly different in emphasis, but the basic meaning stays close.

Because и is joining two clauses, and each clause has its own grammatical center.

Clause 1:

• В июне дни длиннее

Clause 2:

• вечером мне легче гулять после работы

So the comma is normal here.

Russian often uses a comma before и when it joins two full clauses, especially when each part has its own separate idea.

Yes, but it would mean something slightly different in structure.

• В июне дни длиннее = In June, the days are longer
• В июне длинные дни = In June, the days are long

So длиннее is comparative, while длинные is just a plain adjective.

If the sentence is specifically comparing June with some other time of year, длиннее is the right choice.