Learn Hardcore Portuguese (Portugal): Eu lavo a cara com água fria de manhã. - I wash my face with cold water in the morning.

Normal: Lavo a cara.
Emphatic/contrastive or to avoid ambiguity: Lavo a minha cara (possible but less natural in everyday speech).
For someone else’s face: Lavei a cara do bebé or (EP) Lavei‑lhe a cara.

Should I make it reflexive (lavo‑me) when it’s my own face?

Both are acceptable in EP.

Lavo a cara = very common and natural.
Lavo‑me a cara = also common; it can make the “my own face” relationship explicit (you’ll also hear reflexives a lot with hands/hair: lavo‑me as mãos, lavo‑me o cabelo).

If I do use me, where does it go in European Portuguese?

In a simple affirmative: it’s enclitic (after the verb with a hyphen): Lavo‑me a cara de manhã.
With negation and many other triggers, it’s proclitic (before the verb): Não me lavo a cara de manhã.
Common proclisis triggers: negatives (não, nunca), some adverbs (já, ainda, também, só), wh‑words (quem, que, onde), and certain conjunctions (que, se).
Fronted time phrases like De manhã do not force proclisis: De manhã lavo‑me a cara.

Is cara the best word for “face” in Portugal?

cara: everyday, neutral in Portugal.
rosto: more formal/polite or literary.
face: formal/technical. Note: In Brazil, cara can also mean “guy/dude”; in Portugal it does not.

Why is it água fria and not água frio?

Adjectives agree in gender and number with the noun. água is feminine, so the adjective is feminine: fria.

Why is there no article before água fria?

Mass nouns used instrumentally after com often take no article when speaking generally.

General: com água fria
Specific/identified water: com a água fria da torneira, com a água fria que restou

What’s the nuance of de manhã vs na manhã or pela manhã? Anything to avoid?

de manhã = “in the morning” (general/habitual). Most natural in Portugal.
na manhã = “on the morning (of a specific day)”: na manhã de segunda‑feira.
pela manhã exists but sounds more formal and is more Brazilian.
Don’t say à manhã (wrong). And don’t confuse de manhã with amanhã (“tomorrow”).

Can I move de manhã to the start?

Yes. Both are fine:

De manhã, lavo a cara com água fria.
Eu lavo a cara com água fria de manhã.

Does the present tense here mean a habit, or can it mean “right now”?

It’s read as a habit/routine. For “right now,” use the progressive:

EP: Estou a lavar a cara (agora).
BR: Estou lavando o rosto (agora).

How do I pronounce it in European Portuguese?

Approx. IPA: [ew ˈlavu ɐ ˈkaɾɐ kõ ˈaɡwɐ ˈfɾiɐ dɨ mɐˈɲɐ̃]

eu = [ew]
r between vowels is a tap [ɾ] (like Spanish): cara [ˈkaɾɐ]
Final unstressed a often reduces to [ɐ]
com has a nasal vowel; the final “m” isn’t fully pronounced: [kõ]
nh = “ny” sound: manhã [mɐˈɲɐ̃]
de in EP often reduces to [dɨ].

How would Brazilians usually say this?

Common Brazilian phrasing: Eu lavo o rosto com água fria de manhã.

o rosto is preferred/politer than a cara in BR.
The reflexive with body parts is less common in BR; they tend to say Eu lavo o rosto, not Eu me lavo o rosto.

How do I say “I wash my hands in the morning”?

(Eu) lavo as mãos de manhã.
EP also allows: Lavo‑me as mãos de manhã.
Lavo as minhas mãos is possible but sounds emphatic or contrastive, not the default.

Can I say com água gelada instead of com água fria?

Yes, but it changes the feel: gelada suggests “ice‑cold/chilled.” In Portugal, água fria is the normal way to talk about non‑heated water for washing; água gelada is common with drinks or to emphasize very cold water.

Any spelling/diacritics to watch?

água has an acute on the first a.
manhã has a tilde on ã. Don’t write manha (that’s a different word meaning “cunning/spoiled whining”).
de manhã has no article.