Learn Hardcore Indonesian: Ketika cuaca panas, saya cukup berjoging di dalam gedung, tanpa harus keluar ke lapangan. - When the weather is hot, I just jog inside the building, without having to go out to the field.

Kalau cuaca panas, … – very common in speech; can mean if/when the weather is hot. It carries a slight conditional feel, but in everyday use it often just means when.
Waktu cuaca panas, … – more conversational/colloquial; literally at the time (when) the weather is hot.
Saat cuaca panas, … – a bit more formal or written, similar to ketika.

In this sentence, ketika is a neutral, slightly written-sounding choice that focuses on time, not on condition. Replacing it with kalau, waktu, or saat would still be correct, just with small differences in style.

Why is there no word for “is” in cuaca panas? Why not cuaca adalah panas?

In Indonesian, you normally don’t use a verb like “to be” before adjectives.

cuaca panas literally = weather hot → the weather is hot
You do not say cuaca adalah panas in this kind of sentence. Adalah is not used before plain adjectives in simple statements like this.

So:

Ketika cuaca panas, … = When the weather is hot, …

If you want to emphasize that it is currently in a hot period, you might add sedang:

Ketika cuaca sedang panas, … – When the weather is (currently) hot…

You could also say ketika cuaca itu panas, but itu would make it sound like a specific, previously mentioned weather situation; the original sentence talks more generally about any time the weather is hot.

What exactly does cukup mean in saya cukup berjoging di dalam gedung?

Cukup basically means enough, sufficient, and by extension just / simply … is enough.

Common uses:

With adjectives: cukup besar – big enough / quite big
With verbs: cukup tidur 7 jam – sleeping 7 hours is enough

In this sentence:

saya cukup berjoging di dalam gedung ≈ it’s enough for me just to jog inside the building / I just jog inside the building (and that’s sufficient)

Nuance:

cukup emphasizes sufficiency – that doing this is already adequate; nothing more is necessary.
If you said saya berjoging di dalam gedung, it’s a neutral statement: I jog inside the building.
If you said saya hanya/cuma berjoging di dalam gedung, you emphasize only (maybe a bit apologetic or minimizing it).
cukup sits in between: just doing this is already enough; I don’t need to do more or go outside.

Why is it berjoging and not just joging? Are both correct?

The base word here is joging (from English jogging). Adding ber- turns it into a standard intransitive verb meaning to jog:

berjoging = to jog (as an activity)

This pattern is common:

sepeda → bersepeda – to cycle
renang → berenang – to swim
olahraga → berolahraga – to exercise / to do sports

In real life:

Many people do say joging or jogging as a verb in casual speech:
Saya jogging di taman tiap pagi.
In more standard or written Indonesian, berjoging is the safer, more textbook-like form.

So yes, in everyday conversation jogging alone is often accepted, but berjoging is the more formally correct form that learners are usually taught.

What’s the difference between di dalam gedung and just di gedung?

Both can often be translated as in the building, but there is a nuance:

di gedung – at/in the building (quite general)
di dalam gedung – inside the building, with extra focus on being inside rather than outside or just at the location

In this sentence, the contrast is:

di dalam gedung (inside, indoors)
vs.
keluar ke lapangan (go out to the field, outdoors)

So di dalam strengthens that indoors vs outdoors contrast.

You could say saya cukup berjoging di gedung and be understood, but di dalam gedung makes the “inside” aspect clearer.

Why does the sentence say tanpa harus keluar instead of just tanpa keluar?

tanpa = without
harus = must / have to

So:

tanpa keluar ke lapangan = without going out to the field (neutral)
tanpa harus keluar ke lapangan = without *having to go out to the field*

Adding harus introduces the idea of obligation or necessity. The nuance becomes:

I can just jog inside; I *don’t need to / don’t have to go outside to the field.*

A near-equivalent rephrasing:

… saya cukup berjoging di dalam gedung; saya tidak perlu keluar ke lapangan.

So tanpa harus emphasizes that going out would be something required or bothersome, but luckily it isn’t necessary.

Why do we say keluar ke lapangan? Isn’t keluar already “go out”? Why add ke?

You can think of it as:

keluar – to go out / exit (movement from inside to outside)
ke lapangan – to the field (destination)

Together:

keluar ke lapangan = go out (of somewhere) to the field

So the structure is:

[verb of movement] + ke + [place]

similar to:

pergi ke sekolah – go to school
lari ke taman – run to the park
keluar ke halaman – go out to the yard

If you only said tanpa harus ke lapangan, it’s understandable but feels a bit incomplete; usually we’d say tanpa harus pergi ke lapangan in that case.

If you only said tanpa harus keluar, it means without having to go out, but doesn’t specify where you would go.

Can I move ketika cuaca panas to the end of the sentence?

Yes. Both orders are grammatical:

Ketika cuaca panas, saya cukup berjoging di dalam gedung, tanpa harus keluar ke lapangan.
Saya cukup berjoging di dalam gedung, tanpa harus keluar ke lapangan, ketika cuaca panas.

Differences:

Starting with ketika cuaca panas slightly emphasizes the condition/time first.
Putting it at the end sounds more like natural spoken order for some speakers: you state what you do, then add when you do it.

Punctuation:

When the ketika-clause comes first, a comma after it is standard in writing.
When it comes last, you usually don’t need a comma before ketika cuaca panas in everyday writing, though it’s not “wrong” if used for clarity.

Why is saya used here? Could I use aku instead?

Both mean I, but they differ in formality:

saya – neutral/polite, used with strangers, in formal contexts, in writing, with people you are not close to.
aku – informal/intimate, used with friends, family, in casual speech, in songs, etc.

So:

Ketika cuaca panas, saya cukup berjoging di dalam gedung… – sounds neutral/polite, like explaining to someone you’re not very close to, or in a written text.
Ketika cuaca panas, aku cukup berjoging di dalam gedung… – more casual, like talking to a friend.

Grammatically both are correct; the choice depends on the relationship and context.

What does lapangan mean exactly? Is it just “field”?

Lapangan is an open, usually flat area, often used for sports or public activities. Depending on context, it can be:

a sports field: lapangan sepak bola – soccer field
a court: lapangan basket – basketball court
an open square/ground: lapangan kota – town square
a yard/parade ground: lapangan upacara – ceremony ground

In this sentence, because it’s about jogging, lapangan most naturally means some kind of outdoor sports field or open ground where people would normally exercise.

It’s different from:

sawah – rice field
ladang – dry farmland

So translating it as “field” is fine, but specifically more like a sports ground/open field, not farmland.