Bármennyire is rossz az időjárás, elvisszük az esőkabátot és a fejlámpát.

It is a concessive expression: bármennyire is + adjective/adverb... means no matter how ..., however ..., or even if ... is very ....

So Bármennyire is rossz az időjárás means something like:

• No matter how bad the weather is
• However bad the weather is

The word bármennyire is built from:

• bár- = a word element often meaning no matter / any-
• mennyire = how much / how

Together, it gives the sense of however much / no matter how.

Not really. Although is often means also / too, in this kind of structure it has a different function.

In bármennyire is rossz..., the is helps strengthen the concessive meaning: no matter how bad... It is very common after words like:

• bárki is = no matter who
• bárhol is = no matter where
• bármikor is = no matter when
• bármennyire is = no matter how much / however

So here is is not best translated as also. In English, it is often left untranslated.

Both are possible, but they are not identical in feel.

• Az időjárás rossz. = The weather is bad.
  This is a straightforward statement with az időjárás as the topic.

• Rossz az időjárás. = also The weather is bad, but with the adjective in a more prominent position.

In the pattern Bármennyire is rossz az időjárás, Hungarian naturally puts the adjective right after bármennyire is. That is because the structure is really centered on how bad something is.

So rossz az időjárás is the natural word order here.

Hungarian uses the definite article much more often than English.

So az időjárás literally means the weather, and that is the normal way to refer to weather in general or in the current situation.

This is very common in Hungarian:

• süt a nap = the sun is shining
• fúj a szél = the wind is blowing
• rossz az időjárás = the weather is bad

Even where English might use no article, Hungarian often uses a / az.

Elvisszük is the we form of elvinni.

Base idea:

• vinni = to carry / to take
• elvinni = to take away / take along / bring along, depending on context

In this sentence, elvisszük means something like:

• we’ll take
• we’ll bring along

The prefix el- often adds the idea of movement away or of completing the action.

So compared with plain vinni, elvinni often sounds more like taking something with you to another place.

Because Hungarian verbs have definite and indefinite conjugation.

Here the verb has definite objects:

• az esőkabátot
• a fejlámpát

Since the objects are definite, the verb uses the definite conjugation:

• elvisszük = we take it/them

Compare:

• Viszünk egy kabátot. = We are taking a coat.
  -> indefinite object, so viszünk

• Visszük a kabátot. = We are taking the coat.
  -> definite object, so visszük

Also, visz is a somewhat irregular verb, so its forms are worth memorizing.

Those are accusative endings. Hungarian marks direct objects with the accusative case, usually with -t, often with a linking vowel.

So:

• esőkabát -> esőkabátot
• fejlámpa -> fejlámpát

These mean that those nouns are the things being taken.

A few things to notice:

• The basic accusative marker is -t
• Sometimes a vowel appears before it: -ot / -et / -at / -öt
• In fejlámpa -> fejlámpát, the final vowel lengthens: a -> á

This is a very common pattern in Hungarian nouns.

The choice between a and az depends on the next sound:

• az before a vowel sound
• a before a consonant sound

So:

• az esőkabátot because esőkabátot starts with a vowel
• a fejlámpát because fejlámpát starts with a consonant

This is similar to a/an in English, but unlike English, Hungarian uses both forms as versions of the definite article.

Fejlámpa literally means head-lamp:

• fej = head
• lámpa = lamp

It refers to a lamp/light worn on the head, usually with a strap. In English, the usual equivalent is:

• headlamp
• or head torch in British English

So it is a single compound noun, which Hungarian forms very naturally.

Because Hungarian usually does not need subject pronouns when the verb ending already shows the subject.

In elvisszük, the ending tells you the subject is we.

So Hungarian can simply say:

• elvisszük = we take / we’ll take

You could add mi for emphasis, but it is not necessary:

• Mi elvisszük... = We will take it...
  This sounds more contrastive or emphatic.

Hungarian often uses the present tense to talk about the future when the context makes it clear.

So elvisszük can mean:

• we take it
• we are taking it
• we’ll take it

In this sentence, the meaning is naturally future or planned future: they are saying what they will take along.

Hungarian can also make the future more explicit with fog:

• el fogjuk vinni

But in everyday Hungarian, the simple present is often the most natural choice for planned future actions.

Yes. The first part is a subordinate clause:

• Bármennyire is rossz az időjárás

The second part is the main clause:

• elvisszük az esőkabátot és a fejlámpát

Hungarian normally separates this kind of concessive clause from the main clause with a comma, just as English does in a sentence like:

• No matter how bad the weather is, we’ll take...

So the comma is standard and important punctuation here.