Learn Hardcore Russian: Иногда дочь становится грустной, когда весь день идёт дождь. - Sometimes my daughter becomes sad when it rains all day.

становится грустной = “becomes sad,” “gets sad.”
A simple “to be” in Russian present tense is usually just omitted:
- Дочь грустная = “The daughter is sad.”

Here the idea is a change of state (she is not sad → she becomes sad when it rains all day), so Russian prefers становиться rather than a simple “is.”

Why is грустной in this form and not грустная?

Грустной here is in the instrumental case (feminine singular: -ой), agreeing with the feminine noun дочь.

With verbs meaning “to become” (like становиться), Russian very often uses the instrumental case for the new state:

Она становится врачом. – She becomes a doctor.
Он стал известным. – He became famous.
Дочь становится грустной. – The daughter becomes sad.

So грустной is the instrumental form of the adjective грустный (“sad”) used as the resulting state after the change.

Is Иногда дочь становится грустной different from Иногда дочь грустная?

Yes, there is a nuance:

Иногда дочь становится грустной…
– Focus on the process of becoming sad. Something (here: rain all day) makes her sad.
Иногда дочь грустная, когда весь день идёт дождь.
– Grammatically fine, but sounds more like you’re just describing her state in those situations, not emphasizing the change. It’s closer to “Sometimes my daughter is sad when it rains all day.”

Both are understandable, but the original with становится is more natural if you want to show the reaction or change caused by the weather.

Why does становиться take the instrumental case (грустной)?

Certain verbs in Russian regularly use the instrumental for a “new role/state/result.” Key ones include:

быть / являться (to be) – especially with professions, roles
становиться / стать (to become)
работать (to work as…)
называться / являться (to be called / to be)

Examples:

Он стал учителем. – He became a teacher.
Она работает переводчицей. – She works as a translator.
Дочь становится грустной. – The daughter becomes (a) sad (person).

So становиться + кем/чем? → instrumental case, and here кем/чем? = грустной.

What aspect and tense is становится, and could we use станет instead?

становится = present tense, imperfective aspect of становиться.
It describes repeated / habitual or ongoing processes:
- Иногда дочь становится грустной – Sometimes she gets sad.
станет = future tense, perfective aspect of стать.
It would mean a single, completed becoming at some point in the future:
- Однажды дочь станет взрослой. – One day the daughter will become an adult.

Because the sentence describes what sometimes happens (a repeated reaction to certain weather), we need imperfective становится, not perfective станет.

Why is there a comma before когда?

In Russian, когда (“when”) introduces a subordinate clause. The main clause:

Иногда дочь становится грустной

and the subordinate time clause:

когда весь день идёт дождь

are separated by a comma:

Иногда дочь становится грустной, когда весь день идёт дождь.

This is a standard rule: most subordinate clauses introduced by когда, что, потому что, если, хотя etc. are separated from the main clause by a comma.

Why is весь день in this form, and what does it express?

Весь день is in the accusative case and expresses duration of time:

весь день – (for) the whole day
целый день – (for) the whole day
два часа – (for) two hours
неделю – (for) a week

Russian often uses a bare accusative of time to mean “for [that length of time]”:

Она читала книгу весь день. – She read a book all day.
Весь день идёт дождь. – It rains the whole day / it rains all day long.

So here, весь день = “for the whole day,” modifying идёт.

What does идёт дождь literally mean, and is it always used for rain?

Literally, идёт дождь is “rain is going / walking,” but idiomatically it just means “it is raining.”

The verb идти is used with several kinds of precipitation / “falling” weather:

идёт дождь – it’s raining
идёт снег – it’s snowing
идёт град – it’s hailing
идёт сильный дождь – there’s heavy rain

You wouldn’t use идти with everything – for example, you don’t say идёт солнце (“the sun is going”). This is a set pattern for certain weather phenomena.

Can I change the word order to когда дождь идёт весь день or дождь идёт весь день?

Yes, you have some flexibility:

когда весь день идёт дождь – neutral, very common.
когда дождь идёт весь день – also correct; slightly more focus on весь день at the end.
когда идёт дождь весь день – possible, but sounds a bit heavier; still understandable.

Outside the когда-clause:

Весь день идёт дождь. – All day it is raining.
Дождь идёт весь день. – The rain goes all day / It’s raining all day.

All are grammatical; the differences are mostly emphasis and rhythm, not correctness.

Why don’t we say “my daughter” explicitly? How would we say that in Russian?

Russian has no articles (“a / the”), and possessives like мой, моя are often omitted when the owner is obvious from context, especially with close family members.

Иногда дочь становится грустной…
In a natural context, this is understood as “my/the daughter”, usually my if I’m talking about my own child.

To be explicit:

Иногда моя дочь становится грустной, когда весь день идёт дождь.
– “Sometimes my daughter becomes sad when it rains all day.”

Both forms are correct; the version without моя is just more concise and typical in everyday speech when it’s clear whose daughter you mean.

Could I also say Иногда дочери становится грустно, когда весь день идёт дождь, and what’s the difference?

Yes, that sentence is natural, but the structure and nuance change:

Иногда дочь становится грустной…
- Grammar: личное (“personal”) construction.
- Subject = дочь (nominative).
- Predicate adjective: грустной (instrumental).
- Sense: “The daughter becomes (a) sad (person).” Slightly more “descriptive” of what she is like.
Иногда дочери становится грустно…
- Grammar: безличное (“impersonal”) construction.
- дочери is dative = “to the daughter.”
- грустно is a predicative adverb (“sad” in the sense of “it is sad for her”).
- Sense: “Sometimes my daughter feels sad when it rains all day.”

The second version focuses more directly on her inner feeling (“it becomes sad for her”), and is very common when talking about emotions.

Is идёт here like English “is raining” (continuous), or just “rains” (simple present)?

Russian doesn’t have a special progressive/continuous form like English. The simple present идёт can cover both meanings, depending on context:

Смотри, идёт дождь. – Look, it’s raining (right now).
Когда весь день идёт дождь, дочь становится грустной.
– When it rains all day / when it is raining all day, the daughter gets sad.

In this sentence, идёт describes a typical, repeated situation, so in English you’d probably translate it with a simple present (“when it rains all day”), even though the Russian form is the same as you’d use for “it is raining (now).”