Learn Hardcore German: Der Schnupfen macht mich heute müde.

Schnupfen is a noun, and all nouns are capitalized in German, so it must start with a capital S.
The article der is the definite article “the” for masculine nouns in the nominative case.
So Der Schnupfen = “The cold / sniffles” as the subject of the sentence.

Why is the article der used? What gender is Schnupfen?

Schnupfen is grammatically masculine in German.

Masculine singular, nominative definite article = der.
In this sentence, Der Schnupfen is the subject, so it must be in the nominative case.
Therefore der is the correct article: Der Schnupfen (not die or das).

Why is the verb macht used here, instead of just saying “I am tired”?

The verb machen means “to make / to cause” in this context.

Der Schnupfen macht mich heute müde.
= “The cold makes me tired today.”
German often uses machen + (object) + adjective to express that something causes a state in someone:
- Die Hitze macht mich müde. – The heat makes me tired.
- Lärm macht mich nervös. – Noise makes me nervous.

You could also say:

Ich bin heute wegen des Schnupfens müde. – I am tired today because of the cold.

But the given sentence focuses more directly on the cold as the active cause (it “does” something to you).

Why is it mich and not mir?

Mich is the accusative form of ich (I), and mir is the dative form.

The verb machen here takes a direct object (accusative):

jemanden müde machen – “to make someone tired”

So we need the accusative:

Der Schnupfen (subject, nominative)
macht (verb)
mich (direct object, accusative)
müde (predicative adjective)

Mir (dative) would be wrong in this construction.
You would use mir with verbs that take a dative object, e.g.:

Mir ist kalt. – I am cold.
Es geht mir gut. – I am doing well.

But with machen + jemanden + Adjektiv, it must be mich.

Why does müde go at the end of the sentence?

German has a relatively strict word order rule: the conjugated verb is in second position, and many other elements are pushed toward the end.

The typical structure here is:

Subject – Verb – Object – Predicative adjective
Der Schnupfen – macht – mich – müde.

When you add another element like heute, it’s usually placed after the verb but before the “rest”:

Der Schnupfen (subject)
macht (verb, 2nd position)
mich (object)
heute (time adverb)
müde (adjective / complement at the end)

German often places adjectives that describe a resulting state after the object and toward the end of the clause, so müde naturally comes last here.

Can heute go in other positions, or is Der Schnupfen macht mich heute müde the only correct order?

Heute can move around quite flexibly, but the verb must stay in second position. All of these are correct, with slightly different emphasis:

Der Schnupfen macht mich heute müde.
– Neutral; simple statement.
Heute macht mich der Schnupfen müde.
– Emphasis on today (maybe other days it doesn’t).
Der Schnupfen macht heute mich müde.
– Grammatically possible, but sounds unusual; it stresses mich (“me” as opposed to someone else).
Der Schnupfen macht mich müde heute.
– Understandable, but feels a bit colloquial or marked; standard German usually prefers heute earlier.

The most natural everyday versions are (1) and (2).

Is Schnupfen exactly the same as “a cold,” or is there a difference from Erkältung?

They’re related but not identical in nuance:

Schnupfen
- Literally: runny nose / sniffles.
- Often refers specifically to the nasal symptoms: stuffy nose, runny nose, sneezing.
- You can have nur Schnupfen (just a runny nose) without feeling very sick.
Erkältung
- A common cold as an illness: sore throat, cough, a bit of fever, plus often Schnupfen.
- More like the whole “I’ve caught a cold” situation.

In everyday speech, people sometimes use Schnupfen loosely to mean “my cold”, focusing on the runny-nose aspect. In your sentence, the idea is that this head-cold-type thing is making you tired.

Could I also say Ich bin heute wegen des Schnupfens müde? What is the difference in meaning or style?

Yes, that sentence is correct and natural:

Ich bin heute wegen des Schnupfens müde.
= I am tired today because of the cold.

Differences:

Der Schnupfen macht mich heute müde.
- Focuses on the cold as an active cause (“The cold makes me tired”).
- Stylistically a bit more direct and dynamic.
Ich bin heute wegen des Schnupfens müde.
- Describes your state (“I am tired today”) and then gives the reason (“because of the cold”).
- A bit more neutral, explanatory.

Both are common; which you choose depends on what you want to emphasize: the cause doing something to you vs. your state with a reason.

How would I negate this sentence to say “The cold does not make me tired today”?

You would use nicht to negate the verb phrase:

Der Schnupfen macht mich heute nicht müde.
= The cold does not make me tired today.

Placement:

nicht usually comes before the part you want to negate and before a final adjective like müde.
Word order:
- Der Schnupfen (subject)
- macht (verb)
- mich (object)
- heute (time adverb)
- nicht (negation)
- müde (adjective at the end)

You could also say:

Heute macht mich der Schnupfen nicht müde.
– Today, the cold does not make me tired.

Can I drop the article and just say Schnupfen macht mich heute müde?

Yes, this is grammatically possible, but it sounds a bit different:

Der Schnupfen macht mich heute müde.
- More specific: “the (current / particular) cold” that you have now.
- This is what you’d normally say about your own cold.
Schnupfen macht mich heute müde.
- More general or abstract: “cold symptoms / having a cold makes me tired today.”
- Could sound like you’re making a general statement about the condition.

In everyday conversation about your current cold, German speakers almost always use the article: Der Schnupfen macht mich heute müde.