Learn Hardcore Ukrainian: Моя подруга носить капелюх у сонячний день.

друг = a male friend.
подруга = a female friend. If you mean a romantic girlfriend, say дівчина (as in моя дівчина). Подруга usually implies a non-romantic female friend.

Why is it моя подруга and not мій подруга?

The possessive must agree with the noun’s gender and number. Подруга is feminine, so use моя.

мій (masculine): мій капелюх
моя (feminine): моя подруга
моє (neuter): моє місто
мої (plural): мої друзі / мої подруги

What does носить express here—habit or something happening right now?

The Ukrainian simple present can express both, but with носити it is typically read as a habitual/general action. So Вона носить капелюх у сонячний день sounds like a regular habit. For “is wearing right now,” more natural options are:

Вона зараз у капелюсі (She is in a hat right now)
Вона щойно одягла/надягла капелюх (She has just put on a hat)

What’s the difference between носити, одягати, надягати, and вдягати?

носити: to wear (habitually) or to carry around; 3rd person singular: носить.
одягати (impf.) / одягнути/одягти (pf.): to put clothes on (yourself or someone); very common and accepted.
надягати (impf.) / надягти (pf.): to put a specific item on the body (e.g., надягати капелюх). Many style guides prefer this with a particular item.
вдягати/вдягнути: widely used colloquially for “put on.”
Key point: носити = “to wear,” not “to put on.”

Why doesn’t капелюх change its ending after носить?

It’s in the accusative as the direct object of носить. For inanimate masculine nouns, accusative singular = nominative singular, so капелюх stays the same. With animate masculine nouns, accusative looks like genitive (e.g., бачу друга “I see a friend”).

Why is it у сонячний день and not в сонячний день?

у and в are euphonic variants of the same preposition. Choose the one that sounds smoother in context. Between consonants, Ukrainian prefers the vowel у: капелюх у сонячний день. В сонячний день isn’t wrong; it just sounds heavier here.

What case is сонячний день here, and why?

Accusative singular. In time expressions, у/в + accusative can mean “on/in (a time).” So у сонячний день = “on a sunny day.” The adjective сонячний agrees with день in gender, number, and case.

Why is it сонячний, not сонячна or сонячного?

Agreement:

день is masculine, singular, inanimate.
In the accusative singular for inanimate masculine nouns, the form matches the nominative: сонячний день.
Compare:
Feminine object: у сонячну погоду (in sunny weather)
Plural: у сонячні дні (on sunny days)

Can I use на for time, as in на сонячний день?

Not for this meaning. На + accusative with time is typically for scheduling/deadlines (e.g., на понеділок = “for Monday”). To say “on a sunny day,” use у/в + accusative (у сонячний день) or a phrase like у сонячну погоду (“in sunny weather”).

Would plural sound more natural for a habitual statement?

Yes. For a general habit, Моя подруга носить капелюх у сонячні дні (“on sunny days”) sounds very natural.

Are there articles in Ukrainian? How do I know if it’s “a hat” or “the hat”?

Ukrainian has no articles. Капелюх can mean “a hat” or “the hat” depending on context. If the hat is known/specific from context, it reads as “the hat”; otherwise it’s naturally “a hat.”

Can I change the word order?

Yes. Ukrainian word order is flexible and used for emphasis. For example:

У сонячний день моя подруга носить капелюх (emphasis on the time frame)
Капелюх моя подруга носить у сонячний день (emphasis/contrast on “hat”)
The original order is neutral and straightforward.

Is капелюх the right word? What about шапка or кепка?

капелюх: a brimmed hat (sun hat, fedora).
шапка: a warm knit cap/beanie (for cold weather).
кепка: a cap with a visor (baseball cap).
On sunny days, капелюх or кепка are typical; шапка is for cold.

Why not say моя друга for “my female friend”?

Because друг (friend) is masculine; the feminine counterpart is подруга. Моя друга usually reads as “my second” (feminine form of the ordinal “second”) or as part of a different case form. Use моя подруга for “my female friend.”

How is носити conjugated in the present?

я ношу
ти носиш
він/вона/воно носить
ми носимо
ви носите
вони носять

Are there other natural ways to say the same idea?

Yes:

Коли сонячно, моя подруга носить капелюх.
У сонячну погоду моя подруга носить капелюх.
Моя подруга носить капелюх у сонячні дні.