Det blir ofta varmt före åskan på sommaren.

Here det is a dummy subject, like English it in It gets warm.

So Det blir ofta varmt means It often gets warm or It is often warm.

In weather, time, and general-condition statements, Swedish often uses det even when it does not refer to a specific thing:

• Det regnar. = It is raining.
• Det blir kallt. = It gets cold.

So in this sentence, det does not mean that. It is just the subject required by Swedish grammar.

Blir is the present tense of bli, which means become, get, or sometimes turn.

So:

• Det blir varmt = It gets warm / It becomes warm
• Det är varmt = It is warm

Using blir suggests a change of state or a typical development: first it is not warm, then it becomes warm.

In this sentence, that makes sense because the weather often gets warm before thunder.

In a normal Swedish main clause, the finite verb usually comes in second position. This is the V2 rule.

The structure here is:

• Det = subject
• blir = finite verb
• ofta = adverb
• varmt = complement

So:

• Det blir ofta varmt ...

This is very natural word order in Swedish.

Compare:

• Det blir ofta kallt här. = It often gets cold here.
• Hon kommer alltid sent. = She always arrives late.

Varmt is the neuter form of the adjective varm.

When Swedish uses an adjective with det in expressions about weather, conditions, or general situations, the adjective is often in the neuter singular form:

• Det är kallt.
• Det blir mörkt.
• Det verkar svårt.

That is why you get:

• varm = common gender form
• varmt = neuter form

Since the sentence uses det, Swedish uses varmt.

Both före and innan can often mean before, but they are not always used in exactly the same way.

In this sentence, före is very natural because it is followed by a noun phrase:

• före åskan = before the thunderstorm

A useful rule:

• före is very common before nouns
• innan is very common before clauses

Examples:

• före middagen = before dinner
• innan vi går = before we leave

You can sometimes hear innan åskan too, especially in speech, but före åskan is a very standard and natural choice.

Åskan is the definite form of åska.

• åska = thunder / a thunderstorm in a general sense
• åskan = the thunder / the thunderstorm

In Swedish, weather events are often expressed with the definite form when talking about a typical or expected event:

• före åskan = before the thunderstorm
• efter regnet = after the rain

English does not always use the in the same places, so this can feel strange to English speakers. Swedish often prefers the definite form here.

It can depend on context.

The noun åska can refer to:

• thunder as a weather phenomenon
• a thunderstorm, especially in everyday usage

In this sentence, före åskan is usually understood as before the thunderstorm or before the storm breaks, because the whole sentence is about the weather becoming warm beforehand.

So even if the literal connection is with thunder, the natural meaning in context is often closer to thunderstorm.

På sommaren means in summer or during the summer.

Swedish often uses på with seasons in this kind of general meaning:

• på sommaren = in summer
• på vintern = in winter

This is one of those places where Swedish and English use different prepositions:

• Swedish: på sommaren
• English: in the summer

So although på often means on, here you should understand it as part of the normal Swedish expression for seasons.

It is placed there because it works well as a time expression giving extra context to the whole statement.

The core sentence is:

• Det blir ofta varmt före åskan.

Then på sommaren adds when this usually happens:

• Det blir ofta varmt före åskan på sommaren.

Swedish is fairly flexible with time expressions, so you could also say:

• På sommaren blir det ofta varmt före åskan.

That version puts more emphasis on in summer.

Yes, absolutely.

That is also correct Swedish. Because of the V2 rule, when På sommaren is moved to the front, the finite verb still has to come second:

• På sommaren blir det ofta varmt före åskan.

Notice that you do not say:

• På sommaren det blir ... ❌

Both versions are correct, but the emphasis changes slightly:

• Det blir ofta varmt före åskan på sommaren. = neutral statement
• På sommaren blir det ofta varmt före åskan. = stronger focus on in summer

It expresses a general fact or typical pattern, not one specific occasion.

Clues:

• ofta = often
• present tense blir
• på sommaren = in summer

So the meaning is something like:

• It often gets warm before a thunderstorm in summer.

If you wanted to talk about one specific event, Swedish would usually give more context, for example:

• Det blev varmt före åskan i går. = It got warm before the thunderstorm yesterday.

A very natural English version would be:

• It often gets warm before a thunderstorm in summer.

Depending on context, you could also say:

• It’s often warm before a thunderstorm in summer.
• In summer, it often gets warm before a thunderstorm.

This is useful because Swedish åskan may be definite, but natural English often prefers a thunderstorm in a general statement like this.