Quando il sole è alto, la temperatura cresce in fretta.

Because è is the verb essere (to be) in the he/she/it is form.

• è = is
• The accent is important because it distinguishes it from e, which means and

So:

• il sole è alto = the sun is high
• il sole e la luna = the sun and the moon

Because alto agrees with il sole, which is a masculine singular noun.

In Italian, adjectives usually agree in gender and number with the noun they describe:

• il sole alto = masculine singular
• la luna alta = feminine singular
• i monti alti = masculine plural
• le temperature alte = feminine plural

Here, alto describes sole, not temperatura.

In this sentence, quando can be understood as when in a general, repeated sense, very close to whenever in English.

So the idea is not one single event, but a general truth or regular pattern:

• Quando il sole è alto, la temperatura cresce in fretta.

This means something like:

• When/Whenever the sun is high, the temperature rises quickly.

Italian often uses the present tense this way for general facts.

The comma separates the introductory time clause from the main clause:

• Quando il sole è alto = subordinate clause
• la temperatura cresce in fretta = main clause

This is very similar to English:

• When the sun is high, the temperature rises quickly.

The comma is natural and standard here, especially when the quando clause comes first.

Italian often uses the definite article with nouns where English may leave it out, especially when speaking about something in a general sense.

So:

• la temperatura cresce = the temperature rises

Even though English sometimes uses no article in broader statements, Italian usually prefers the article here.

Compare:

• La vita è bella. = Life is beautiful.
• Il tempo passa. = Time passes.

So la temperatura sounds natural and normal.

Because the subject is la temperatura, which is singular.

Even though the sentence begins with Quando il sole è alto, that part is not the main subject of cresce. The verb cresce belongs to la temperatura:

• la temperatura cresce = the temperature rises

So:

• singular subject → cresce
• plural subject would give crescono

Example:

• Le temperature crescono in fretta. = Temperatures rise quickly.

Yes, aumentare would also be possible in many contexts.

• crescere = to grow, rise, increase
• aumentare = to increase, go up

In this sentence, la temperatura cresce in fretta sounds natural and understandable.
You could also say:

• la temperatura aumenta in fretta

Both work, though aumentare is often the more direct choice for things like prices, numbers, or temperature. Crescere can sound slightly more like a gradual rise or upward movement, but in everyday use there is a lot of overlap.

In fretta is a common expression meaning quickly, fast, or in a hurry depending on context.

Here it means:

• la temperatura cresce in fretta = the temperature rises quickly

It is a fixed expression:

• fare qualcosa in fretta = to do something quickly / in a hurry

You could also use velocemente, but in fretta is very common and natural in everyday Italian.

It is most naturally understood as a general fact or habitual truth.

Italian, like English, often uses the present tense for things that are generally true:

• Quando il sole è alto, la temperatura cresce in fretta.

This is not necessarily about one specific moment. It means something like:

• When the sun is high, the temperature rises quickly.

So this is the present indicative, used for a general statement.

Cresce is pronounced roughly KREH-sheh.

A few useful points:

• cr = like English cr
• e = short Italian eh
• sc before e or i sounds like English sh
• final e is pronounced, not silent

So:

• cresce ≈ KREH-sheh

This is a common pattern:

• scena ≈ SHEH-na
• uscire ≈ oo-SHEE-reh

Fretta is pronounced roughly FRET-ta.

Important detail:

• the tt is doubled, so it is pronounced more strongly than a single t

Italian double consonants matter, and native speakers usually hold or reinforce them slightly.

So try:

• fretta = FRET-ta

Not a huge pause, but definitely a stronger t than in a single-consonant word.

Yes, but the original order is the most neutral and natural for this kind of statement.

Standard version:

• Quando il sole è alto, la temperatura cresce in fretta.

You could also hear different structures in Italian depending on style or emphasis, but this version is clear and typical because it presents:

1. the condition/time frame
2. then the result

That matches the flow of the English sentence very well.