Elle trouve son short plus pratique quand il fait très chaud.

In French, son / sa / ses agree with the thing owned, not with the owner.

• short (meaning “a pair of shorts”) is a masculine singular noun in French: un short.
• Therefore you must use the masculine singular possessive: son short (“her/his short[s]”).

Examples:

• Elle aime son pantalon. (pantalon = masc.)
• Elle aime sa jupe. (jupe = fem.)
• Elle aime ses chaussures. (chaussures = plural)

So even though elle is female, the possessive is son because short is masculine.

French treats this item of clothing as a single garment:

• un short = “a pair of shorts”
• des shorts = “(several) pairs of shorts”

The noun is grammatically singular when you’re talking about one pair. It’s the same idea as:

• un pantalon = a pair of trousers/pants
• un jean = a pair of jeans

So son short means “her shorts” (one pair).

Grammatically, le short is possible, but it doesn’t mean quite the same thing.

• son short = her short(s), the pair that belongs to her.
• le short = the short(s), a specific one already known from context, without explicitly saying it’s hers.

In a neutral sentence like this, French usually uses the possessive to make it clear we’re talking about her own clothing, so son short is the natural choice.

Literally, trouver means “to find”, but in this very common structure it means “to think / to consider”:

• trouver + direct object + adjective

So:

• Elle trouve son short plus pratique
  = “She finds/considers her shorts more practical”
  = “She thinks her shorts are more practical.”

More examples:

• Je trouve ce film intéressant. = I think this film is interesting.
• Nous trouvons cette solution trop compliquée. = We think this solution is too complicated.

You can say that; both structures are correct:

1. Elle trouve son short plus pratique.

   • Structure: trouver + noun + adjective
   • Slightly more compact and very common.

2. Elle trouve que son short est plus pratique.

   • Structure: trouver que + clause
   • Also very natural, maybe a bit more explicit.

Meaning-wise, they’re essentially the same: she thinks her shorts are more practical.

plus pratique is a comparative: “more practical”.

• Pattern: plus + adjective = more + adjective
  • plus pratique = more practical
  • plus grand = bigger
  • plus intéressant = more interesting

Related forms:

• moins pratique = less practical
• aussi pratique = as practical
• le plus pratique = the most practical

Here, plus pratique describes short: “her shorts are more practical (than something else understood from context).”

In this sentence, plus is a positive comparative (“more”), and it comes before an adjective. In that case, you normally:

• pronounce it /ply/, like “plü”
• do not pronounce the s
• no liaison with the next word

So plus pratique is pronounced roughly: /ply pra.tik/.

By contrast:

• In ne ... plus (“no longer”), you usually say the s: /plys/.
• In some careful speech with plus que, you may also hear the s: /plys kə/.

Literally, quand il fait très chaud is “when it makes very hot”, but idiomatically it means “when it’s very hot (outside)”.

French uses special weather expressions:

• Il fait chaud. = It’s hot (weather).
• Il fait froid. = It’s cold.
• Il fait beau. = The weather is nice.

You normally don’t say:

• ✗ quand c’est très chaud
• ✗ quand il est très chaud

for general weather. Instead, you use il fait + adjective.

Here il is an impersonal pronoun. It doesn’t refer to a person or a specific thing; it’s just a dummy subject used in weather expressions.

Other examples:

• Il pleut. = It’s raining.
• Il neige. = It’s snowing.
• Il fait froid. = It’s cold.

So in quand il fait très chaud, il doesn’t mean “he”; it just introduces the weather phrase.

Yes. Both word orders are correct:

• Elle trouve son short plus pratique quand il fait très chaud.
• Quand il fait très chaud, elle trouve son short plus pratique.

Putting the quand-clause first just changes the emphasis slightly (starting with the time condition), but it doesn’t change the meaning.

• très chaud = very hot (strong intensity, but neutral)
• trop chaud = too hot (excessive, more than desirable)

So:

• quand il fait très chaud = when it’s very hot
• quand il fait trop chaud = when it’s too hot (implying a problem)

In informal speech, trop is sometimes used like “really/so” (“c’est trop bien !”), but in standard usage trop keeps the idea of “too much”.

Yes, pratique is an adjective describing short, so it must agree with it.

• short is masculine singular → pratique (no change in spelling)
• If the noun were plural:
  
  • Elle trouve ces shorts très pratiques. (masc. plural)
• If it were feminine singular:
  
  • Elle trouve cette jupe pratique. (fem. singular; same spelling here)
• Feminine plural:
  
  • Elle trouve ces chaussures pratiques.

In this particular case, pratique looks the same in masculine and feminine singular, so you don’t see a visible change, but the rule still applies.

Yes, you can say:

• Elle trouve son short plus pratique lorsqu’il fait très chaud.

lorsque and quand both mean “when” in time expressions. Differences:

• lorsque is often a bit more formal or literary.
• In everyday spoken French, quand is more common.

Here they’re interchangeable in meaning.