Σήμερα δεν έχει καύσωνα, αλλά η υγρασία είναι μεγάλη, παρόλο που η πρόγνωση έλεγε κάτι άλλο.

Greek often uses έχει (it has / there is) in impersonal weather expressions.

So έχει καύσωνα is a normal Greek way to say that heatwave conditions exist. It does not literally feel like English it has a heatwave to Greek speakers; it is just a standard weather pattern.

You will hear similar expressions such as:

• έχει ζέστη = it’s hot
• έχει κρύο = it’s cold
• έχει αέρα = it’s windy
• έχει ομίχλη = it’s foggy

Greek often avoids the dummy subject it that English needs in weather sentences.

Because καύσωνα is the accusative singular form of ο καύσωνας.

• Nominative: ο καύσωνας
• Accusative: τον καύσωνα

After έχει, the noun functions like a direct object, so Greek uses the accusative:

• Έχει καύσωνα.

This is very common in Greek weather expressions and fixed phrases.

Because Greek often leaves out the article when talking about a general condition or phenomenon in expressions like this.

So:

• έχει καύσωνα = there is a heatwave / it’s heatwave-level hot

This sounds more natural than using the article in this sentence. If you said έχει τον καύσωνα, it would usually sound wrong here.

ζέστη means heat / hot weather in a general sense.

καύσωνας is much stronger: it means heatwave, usually a period of unusually intense heat.

So:

• Έχει ζέστη = it’s hot
• Έχει καύσωνα = there’s a heatwave / it’s extremely hot

A learner should think of καύσωνας as a more specific and more intense word.

In Greek, δεν normally goes directly before a finite verb in ordinary negative statements.

So:

• δεν έχει = does not have / there isn’t

That is the normal position. Greek does not place the negative after the verb the way some other languages do.

Also, this is δεν, not μη(ν), because δεν is used for ordinary factual negation in the indicative.

Here μεγάλη means high / great, not literally big in a physical-size sense.

With things like humidity, pressure, risk, or importance, Greek often uses μεγάλος / μεγάλη / μεγάλο in a broader sense:

• μεγάλη υγρασία = high humidity
• μεγάλος κίνδυνος = great danger
• μεγάλη σημασία = great importance

You may also hear υψηλή υγρασία and sometimes πολλή υγρασία, but μεγάλη υγρασία is perfectly natural.

Because both nouns are feminine singular nominative, and Greek uses the article very regularly.

• η υγρασία = the humidity
• η πρόγνωση = the forecast

Greek uses definite articles more often than English does. In many cases where English might say just humidity or forecast, Greek still naturally says η υγρασία and η πρόγνωση, especially when referring to the specific humidity and the specific forecast in the situation being discussed.

παρόλο που means although / even though / despite the fact that.

It introduces a subordinate clause:

• παρόλο που η πρόγνωση έλεγε κάτι άλλο

A useful thing to remember is that παρόλο που is followed by a normal finite verb, usually in the indicative:

• παρόλο που βρέχει... = although it’s raining...
• παρόλο που είπε... = although he/she said...

It is a very common way to express contrast.

έλεγε is the imperfect of λέω.

In this sentence, the imperfect gives the idea of what the forecast was saying / was predicting. It sounds like background information rather than a single sharp event.

That is why έλεγε works well here: the forecast had been indicating something different.

If you changed it to είπε, that would sound more like:

• the forecast said something different at one specific moment

Both can be possible in some contexts, but έλεγε is very natural when referring to what a forecast was showing or predicting.

Because κάτι άλλο is the normal Greek order for something else.

• κάτι = something
• άλλο = other / else

So together:

• κάτι άλλο = something else

This is a fixed, very common pattern.
Similarly:

• κάποιος άλλος = someone else
• κάπου αλλού = somewhere else

άλλο κάτι is not the normal order for this meaning.

Putting Σήμερα first sets the time frame immediately: today.

Greek word order is flexible, so speakers often move time words to the front for emphasis or clarity. Starting with Σήμερα makes it clear from the beginning that the whole comment is about today’s conditions.

The sentence could be rearranged in other ways, but this version sounds very natural and clear.

The structure is:

• Σήμερα = time expression
• δεν έχει καύσωνα = first main clause
• αλλά = but
• η υγρασία είναι μεγάλη = second main clause
• παρόλο που η πρόγνωση έλεγε κάτι άλλο = subordinate concessive clause

Greek word order is more flexible than English because noun endings and articles give grammatical information. But this sentence is actually quite straightforward and natural:

1. set the time
2. state one fact
3. contrast it with another fact
4. add a clause of concession: although the forecast said otherwise

A few useful pronunciation notes:

• Σήμερα → SEE-me-ra
• καύσωνα → KAF-so-na
• υγρασία → ee-gra-SEE-a
• παρόλο → pa-RO-lo
• πρόγνωση → PROG-no-see
• έλεγε → E-le-ye

A very important rule: the written accent mark shows the stressed syllable.

So:

• Σήμερα would be wrong, but Σήμερα is not how the word is written
• Σήμερα is stressed on σή / si
• υγρασία is stressed on -σί-
• πρόγνωση is stressed on πρό-

Learning to notice the accent marks will help your pronunciation a lot.