Learn Hardcore Finnish: Pysymme lämpiminä talvella pukeutumalla kunnolla ja juomalla kuumaa teetä. - We stay warm in winter by dressing properly and drinking hot tea.

Olemme lämpimiä. = We are warm. (state, as a simple fact)
Pysymme lämpiminä. = We stay/keep warm. (the state continues, usually thanks to some method)

In this sentence, the point is that we manage to remain warm because of dressing properly and drinking hot tea. That’s why pysyä is used instead of olla.

Why is lämpiminä in that strange form and not just lämpimänä or lämpimät?

Lämpiminä is:

from the adjective lämmin (warm)
in plural essive case

Breakdown:

Stem: lämmin → lämpimä- / lämpim-
Plural stem: lämpimi-
Essive plural ending: -nä
→ lämpimi- + nä = lämpiminä

The essive case (often “as / in the state of”) is used as a predicative after verbs like:

olla (to be)
pysyä (to stay, remain)
käydä (to go as / function as)

Examples:

Olemme väsyneinä. – We are tired (in a tired state).
Pysymme lämpiminä. – We stay warm (in a warm state).

It’s plural because the subject is “we” (me), and in Finnish predicative adjectives usually agree in number and case with the subject:

Minä pysyn lämpimänä. – I stay warm. (singular essive: lämpimänä)
Me pysymme lämpiminä. – We stay warm. (plural essive: lämpiminä)

So lämpiminä = “in a warm state (all of us)”.

What is talvella grammatically, and how does it mean “in winter”?

Talvella comes from talvi (winter) and is in the adessive case:

talvi → stem talve- → talvella

The adessive -lla/-llä usually means:

“on” (on the table – pöydällä)
“at / by” (at the station – asemalla)

But with time words, it often means “in / during”:

kesällä – in summer
yöllä – at night
jouluna is essive, but joulunaikaan / joululla can appear in dialects, etc.

So talvella translates as “in winter / during winter” in a general, habitual sense.

What is the -malla ending in pukeutumalla and juomalla, and how does it work?

Pukeutumalla and juomalla are MA‑infinitive forms (3rd infinitive) in the adessive case. Their main function is to express “by doing X” / “through X”:

pukeutua → pukeutuma- → pukeutumalla = “by dressing (oneself)”
juoda → juoma- → juomalla = “by drinking”

In this sentence they work as adverbials of manner/means:

pukeutumalla kunnolla – by dressing properly
juomalla kuumaa teetä – by drinking hot tea

So the structure is:

Pysymme lämpiminä … pukeutumalla … ja juomalla …
We stay warm by dressing properly and by drinking hot tea.

This -malla/-mällä form is very common and directly corresponds to English “by -ing”.

Why does pukeutua automatically mean “to dress oneself”? Where’s “ourselves” in pukeutumalla?

In Finnish, some verbs are inherently reflexive or middle voice by their structure, often with -utua / -ytyä endings:

pukea = to dress (someone/something)
pukeutua = to dress oneself, to get dressed

So pukeutua already carries the meaning “dress oneself” without needing an extra word like “itse” (self).

Thus:

pukeudun – I get dressed / I dress myself
pukeudumme – we get dressed
pukeutumalla – by getting dressed (ourselves)

You can add itse for emphasis:

pukeutumalla itse kunnolla – by dressing ourselves properly (stronger emphasis)

But in normal speech pukeutua alone is enough.

What does kunnolla mean exactly? Is it the same as hyvin?

Kunnolla is an adverb derived from kunto / kunnon and basically means:

properly, appropriately, thoroughly, in a decent/correct way

Nuance compared to hyvin:

hyvin = well (wide meaning: well-done, good, nicely, skillfully, etc.)
kunnolla = properly / as one should / not half‑heartedly

Examples:

Pukeudu kunnolla, ulkona on kylmä. – Dress properly, it’s cold outside.
En ole vielä oppinut tätä kunnolla. – I haven’t properly learned this yet.

In this sentence, pukeutumalla kunnolla suggests dressing sensibly and adequately for the cold, not just “a bit well”.

Does pukeutumalla kunnolla ja juomalla kuumaa teetä describe two separate ways of staying warm?

Yes. You have two parallel -malla phrases joined by ja (and):

pukeutumalla kunnolla – by dressing properly
juomalla kuumaa teetä – by drinking hot tea

Both modify pysymme lämpiminä. So the meaning is:

We stay warm in winter by dressing properly and by drinking hot tea.

They’re separate actions, both contributing to the same result.

Why is kuumaa teetä in the partitive case? Why not just kuuma tee?

Kuumaa teetä is:

kuuma (hot) → partitive singular kuumaa
tee (tea) → partitive singular teetä

In Finnish, the partitive case is used for:

Indefinite or uncountable amounts (“some tea”)
Ongoing or incomplete actions
Many objects of infinitive/ma-forms when the quantity is not total

Here, juomalla kuumaa teetä literally means:

“by drinking (some) hot tea”

We don’t mean one whole, specific portion that gets completely finished; it’s an indefinite amount of tea used to keep warm.

Compare:

Juon teetä. – I drink tea / I’m drinking tea. (some, in general)
Juon teen. – I drink / will drink the (one) tea (e.g. one cup, completely).

So kuumaa teetä fits the idea of drinking tea as a means, not focusing on one finite portion.

Could I say juomalla kuuman teen instead of kuumaa teetä?

You could grammatically, but the nuance changes and it sounds less natural here.

kuumaa teetä (partitive) = some hot tea, an indefinite amount
kuuman teen (genitive) would imply a specific, total tea (like one whole cup that will be completely drunk) as the object of the action.

Juomalla kuuman teen pysymme lämpiminä would sound like:

We stay warm by drinking (up) one hot tea.

The original sentence is more general and natural:

juomalla kuumaa teetä – by drinking hot tea (as a general habit / in some amount).

Why is there no explicit me (“we”) in the sentence? Is pysymme alone enough?

Yes. In Finnish, personal pronouns are often dropped when the verb ending already shows the person:

pysymme = we stay
pukeudumme = we dress (ourselves)
juomme = we drink

So:

Me pysymme lämpiminä.
Pysymme lämpiminä.

Both are correct; the version without me is perfectly normal and slightly more neutral. You typically use me for emphasis or contrast:

Me pysymme lämpiminä, mutta he palelevat.
We stay warm, but they are freezing.

Could I say the same thing without using the -malla forms?

Yes. A common alternative is to use a subordinate clause with “kun”:

Pysymme lämpiminä talvella, kun pukeudumme kunnolla ja juomme kuumaa teetä.
We stay warm in winter when we dress properly and drink hot tea.

Meaning is very close:

-malla version: how/by what means we stay warm
kun-clause: under what condition / when we stay warm

Both are natural; the original is just more compact and a bit more “written-style”.

What time meaning does pysymme have here—present, future, or general habit?

Finnish present tense is used for:

Present time: Nyt pysymme lämpiminä. – We are staying warm now.
Near future: Huomenna pysymme lämpiminä. – Tomorrow we’ll stay warm.
General truths / habits: Talvella pysymme lämpiminä… – In winter we (generally) stay warm…

In this sentence, with talvella and no specific time marker, pysymme is best read as a general, habitual statement:

In winter, we keep warm by dressing properly and drinking hot tea.