El viento venía del noreste y hacía bastante frío.

Because the sentence is describing background conditions in the past, not a single completed event.

In Spanish, the imperfect is very common for:

• weather
• time
• age
• ongoing situations
• descriptions in the past

So:

• El viento venía del noreste = the wind was coming from the northeast / used to come from the northeast
• hacía bastante frío = it was quite cold

If you used the preterite instead, it would sound more like a specific, completed event rather than a general scene or ongoing condition.

Spanish often uses hacer for weather expressions.

Common examples:

• hace calor = it’s hot
• hace frío = it’s cold
• hacía viento = it was windy
• hacía sol = it was sunny

So hacía bastante frío literally looks like it made quite cold, but that is just how Spanish expresses weather. You should learn hacer + weather noun/adjective-like expression as a set pattern.

Because de + el contracts to del in Spanish.

So:

• de + el = del

That is why:

• venía del noreste = was coming from the northeast

This contraction is required in normal Spanish.

A useful exception:

• de + el does not contract when el is part of a proper name, such as de El Escorial.

Spanish usually does not use a dummy subject like English it in weather expressions.

English says:

• It was cold
• It was raining

Spanish normally just says:

• hacía frío
• llovía

The subject is simply understood from the verb or from the kind of expression being used.

Yes, literally venía comes from venir, meaning to come. But in weather or direction contexts, English often translates it more naturally as:

• was coming from
• came from
• was blowing from when talking about wind

So in this sentence, El viento venía del noreste means the wind’s direction was from the northeast.

In natural English, The wind was coming from the northeast or The wind was blowing in from the northeast both fit well.

Yes. Soplar means to blow, and it is very common with wind.

So:

• El viento venía del noreste
• El viento soplaba del noreste

Both are possible.

The difference is:

• venía del noreste focuses on the direction it was coming from
• soplaba del noreste focuses more directly on the wind blowing

Both sound natural, but venir de is a very normal way to describe where wind comes from.

Here bastante means quite, fairly, or rather.

So:

• hacía bastante frío = it was quite cold

It softens the statement a little compared with something stronger like:

• hacía mucho frío = it was very cold / really cold

A useful point:

• bastante can work as an adverb: bastante frío
• it can also be an adjective/pronoun in other contexts: bastantes libros = quite a lot of books

Because frío here is not agreeing with a feminine noun. In the expression hacer frío, frío functions as part of a fixed weather expression.

Compare:

• Hace frío = It’s cold
• La noche es fría = The night is cold

In La noche es fría, fría agrees with la noche. But in hace frío, there is no noun that frío is agreeing with in that way.

The accent marks show the stress and also help distinguish the pronunciation.

• venía is pronounced roughly beh-NEE-a
• hacía is pronounced roughly a-THEE-a in most of Spain, or a-SEE-a in Latin American pronunciation

The accent marks show that the í forms its own syllable:

• ve-ní-a
• ha-cí-a

Without the accent, Spanish pronunciation rules would suggest a different stress pattern.

In most of Spain:

• hacía is pronounced roughly a-THEE-a

Notes:

• the h is silent
• the c before i is usually pronounced like the th in think in most of Spain
• the stress falls on cí

So it sounds approximately like:

• a-THEE-a

In parts of southern Spain and in Latin America, you may hear a-SEE-a instead.

Spanish very often uses the definite article where English may or may not use one.

So:

• El viento = the wind

When talking about weather or natural phenomena in a general but specific scene, Spanish commonly uses the article:

• El sol brillaba
• La lluvia caía
• El viento venía del noreste

In English, we also naturally say the wind in this sentence, so the article matches well here.

Not normally. Bastante is placed before the adjective/adverb it modifies here:

• hacía bastante frío

That is the natural order.

Putting bastante after frío would sound wrong in standard Spanish in this sentence.

Because Spanish, like English, often links two background descriptions with y:

• El viento venía del noreste y hacía bastante frío.

This creates one continuous picture of the scene:

• wind direction
• temperature

It is especially natural because both verbs are in the imperfect and describe the same past setting. Splitting them into two sentences is possible, but using y sounds smooth and connected.