Learn Hardcore Norwegian: Jeg var trøtt hele dagen.

Jeg = I
var = was (past tense of å være = to be)
trøtt = tired
hele = whole / entire / all (of the)
dagen = the day (dag = day, -en is the definite ending the)

So the structure is very similar to English: I was tired all (the) day.

Why is the past tense var used here instead of er or har vært?

var = simple past (was):
Jeg var trøtt hele dagen. = I was tired all day (yesterday / earlier).
er = present (am / is / are):
Jeg er trøtt hele dagen. is normally wrong in standard Norwegian, because hele dagen describes a finished time span in the past or on a specific day, not a general habit right now.
har vært = present perfect (have been):
Jeg har vært trøtt hele dagen. = I have been tired all day.
This is used when the day is still ongoing (for example, you say it in the evening of the same day).

So:

Talking about an earlier, finished day → var
Talking about today so far → har vært

How is the verb å være (to be) conjugated in Norwegian?

The main forms you’ll meet early on:

infinitive: å være = to be
present: er = am / is / are
- Jeg er trøtt. – I am tired.
past (preterite): var = was / were
- Jeg var trøtt. – I was tired.
past participle: vært (used with har / hadde)
- Jeg har vært trøtt. – I have been tired.

In spoken usage, these are the core forms you need.

Why is the adjective trøtt not changing form to match jeg? Should it agree in gender or number?

In Jeg var trøtt, trøtt is a predicative adjective (an adjective after to be that describes the subject).

In Norwegian, predicative adjectives after å være usually appear in the base form (the common-gender singular form), regardless of whether the subject is:

masculine, feminine, or neuter
singular or plural

Examples:

Jeg er trøtt. – I am tired.
Hun er trøtt. – She is tired.
Vi er trøtte. – We are tired. (plural form trøtte is also possible here, but in many dialects people still say Vi er trøtt in speech.)

In Jeg var trøtt, using trøtt is the normal, neutral choice and does not change with jeg.

What is the difference between trøtt, sliten, and søvnig?

All can be translated with tired in English, but they have different nuances:

trøtt
- General tiredness; can be from lack of sleep, long day, mentally drained, etc.
- Very common and neutral.
- Jeg var trøtt hele dagen. – I was tired all day.
sliten
- More like exhausted / worn out, often after physical or mental effort.
- Suggests you have been working, stressing, or doing something demanding.
- Jeg var sliten etter jobb. – I was worn out after work.
søvnig
- Specifically sleepy, wanting to sleep.
- Jeg var søvnig hele dagen. – I was sleepy all day.

In everyday speech, trøtt covers a lot of what English tired covers.

Why is it hele dagen and not hele dag or all dagen?

Several points:

Whole + a specific day → definite form
- In Norwegian, when you mean the whole of a specific day, you make the noun definite:
  - hele dagen = the whole day / all day
  - hele uka = the whole week
  - hele natten = the whole night
Why not hele dag?
- hele dag (without -en) is generally wrong in this meaning.
- It would sound incomplete, like saying whole day instead of the whole day.
Why not all dagen?
- Norwegian does not use all in front of a noun the same way English does.
- Instead, hele does that job: hele dagen, hele huset, hele verden.

So hele dagen is the natural way to say all day / the whole day.

Can you add i and say Jeg var trøtt i hele dagen?

No, not in this meaning. Jeg var trøtt i hele dagen is ungrammatical or at least very unnatural.

For I was tired all day, you simply say:
- Jeg var trøtt hele dagen. (no preposition)

You do use i with some time expressions:

i dag – today
i går – yesterday
i morgen – tomorrow
i tre dager – for three days

…but with hele dagen, the normal pattern is no preposition.

Can I move hele dagen to the front, like Hele dagen var jeg trøtt?

Yes, and that is correct Norwegian, but the emphasis changes:

Jeg var trøtt hele dagen.
- Neutral, unmarked word order.
- Focus: I was tired, and by the way, it lasted all day.
Hele dagen var jeg trøtt.
- More emphasis on the entire day.
- Feels a bit more dramatic/literary or used when contrasting with another day or time:
  - Hele dagen var jeg trøtt, men om kvelden ble jeg mer våken.
    All day I was tired, but in the evening I became more awake.

Both are grammatically correct.

What is the difference between hele dagen and hele dagen lang?

hele dagen = all day / the whole day (standard, neutral)
hele dagen lang = all day long

lang adds a bit of extra emphasis on the duration, similar to English all day long, which can sound a bit more expressive:

Jeg var trøtt hele dagen. – I was tired all day.
Jeg var trøtt hele dagen lang. – I was tired all day long. (more emphatic)

How do you pronounce trøtt, hele, and dagen?

Approximate pronunciation in standard Eastern Norwegian:

Jeg var trøtt hele dagen.
[jæi vɑr trœtː ˈheːlə ˈdɑːɡən] (rough guide)

By word:

trøtt:
- ø like the vowel in French peu or like British u in burn but with more lip rounding.
- Double tt is a fairly short, strong t.
- Rough English approximation: "trutt" with rounded lips on the vowel.
hele:
- he- like hay, but shorter.
- -le is a schwa-like sound: -luh.
- Roughly: "HEH-luh", with stress on HE-.
dagen:
- da- like dah, long a.
- -gen: the g is usually pronounced, then a light en.
- Roughly: "DAH-gen", with stress on DAH-.

Dialects may vary somewhat, but this will be widely understood.

Is Jeg var trøtt hele dagen more like a statement of fact, or can it also sound like a complaint?

It can be both, depending on tone and context.

Neutral:
- Jeg var trøtt hele dagen. – simply reporting what your day was like.
As a complaint or expressing frustration:
- Same sentence, but said with a complaining tone or followed by something like:
  - …så jeg fikk ikke gjort så mye. – so I didn’t get much done.

Norwegian often uses the same literal wording for both neutral statements and mild complaints; the difference is in intonation and surrounding context.

Is trøtt formal, informal, or dialectal?

trøtt is standard, neutral Bokmål, used in both spoken and written Norwegian.
It is neither particularly formal nor particularly slangy.
You will hear it in almost all dialects, even if some might pronounce it slightly differently or also use local words in addition.

So Jeg var trøtt hele dagen. is perfectly normal in everyday conversation and fine in neutral written language.