Learn Hardcore Spanish (Spain): Cuando no hay viento, la nieve parece más tranquila y la temperatura sube un poco. - When there is no wind, the snow seems calmer and the temperature goes up a little.

In Spanish, hay (from haber) is used to say that something exists or is present in a place, especially when talking about indefinite things or weather conditions.

Hay viento = There is wind / It’s windy.
No hay viento = There is no wind / It’s not windy.

Using es viento or está viento is incorrect in this meaning.
For weather, Spanish normally uses:

Hace viento (literally “it makes wind”)
or Hay viento

Both are correct; hay viento emphasizes the presence/absence of wind a bit more, while hace viento feels more like “it’s windy” as a general condition.

Why is the verb in the cuando clause in the present indicative (cuando no hay) and not in the subjunctive (cuando no haya)?

Because the sentence describes a general, habitual situation, not a specific future or uncertain event.

Cuando no hay viento, la nieve parece…
→ “Whenever / When there is no wind, the snow seems…”
This is a general rule. For that, Spanish uses the present indicative (hay).

The subjunctive with cuando appears when you talk about a future, not-yet-real event:

Cuando no haya viento, saldremos a esquiar.
→ “When there is no wind, we’ll go skiing.” (future, not realized yet)

In your sentence, it’s more like a timeless observation, so hay is correct.

Could I say cuando no hace viento instead of cuando no hay viento? Is there a difference?

You can say both; they are both natural:

Cuando no hay viento…
Cuando no hace viento…

Differences in nuance:

Hay viento / no hay viento
Focuses slightly more on the presence/absence of wind.
Hace viento / no hace viento
Is the most common way to say “it’s (not) windy” as a weather condition.

In practice, in this sentence both are fine. No hay viento may sound a bit more descriptive, like detecting that there simply isn’t any wind right now.

Why does nieve have la (definite article), but viento doesn’t?

Spanish often uses the definite article with mass nouns or abstract nouns when speaking about them in a general way:

La nieve = “(the) snow” as a substance in general.
La gente, el agua, el café, etc.

In English we usually drop the article: Snow seems calmer…, but Spanish tends to say la nieve.

With viento in no hay viento, we are talking about any wind at all, so it behaves like an indefinite thing; that’s why there is no article:

Hay viento / No hay viento → “There is (no) wind.”

If you make it specific, you would use an article:

El viento del norte es muy fuerte.
“The north wind is very strong.”

Why is it la nieve parece más tranquila and not más tranquilo?

Because adjectives in Spanish must agree in gender and number with the noun:

La nieve is feminine singular.
Therefore the adjective must also be feminine singular → tranquila.

So:

La nieve está tranquila.
La montaña está tranquila.
El lago está tranquilo.
Las montañas están tranquilas.

What’s the difference between parece, es, and está here? Could I say la nieve está más tranquila?

All three verbs exist, but they don’t mean the same:

parecer = to seem / to appear (subjective impression)
- La nieve parece más tranquila.
  → “The snow SEEMS calmer.” (how it looks/feels to you)
estar = to be in a temporary state/condition
- La nieve está más tranquila.
  → “The snow IS calmer.” (you’re describing its current state)
ser usually isn’t used with tranquilo for snow; ser tranquilo is more for inherent traits, especially of people or places:
- Es un pueblo muy tranquilo. – “It’s a very quiet town.”

In your sentence, parece is a good choice because you’re describing how the snow appears when there is no wind. Está más tranquila would also be acceptable, with a slightly more objective tone (“it is calmer” rather than “it seems calmer”).

Why is it más tranquila (before the adjective) and not tranquila más?

In Spanish, degree adverbs like más, menos, muy, bastante, etc. normally come before the adjective:

más tranquila – “calmer / more calm”
muy tranquila – “very calm”
menos tranquila – “less calm”

The order tranquila más is incorrect in standard Spanish. The pattern is:

más / muy / menos + adjective
La nieve parece más tranquila.

Why is there a comma after Cuando no hay viento?

When a sentence begins with a subordinate clause (here, the cuando clause), Spanish usually places a comma before the main clause:

Cuando no hay viento, la nieve parece más tranquila…
Si llueve, nos quedamos en casa.
Cuando tenga tiempo, te llamaré.

If the cuando clause comes after the main clause, the comma is usually optional or omitted:

La nieve parece más tranquila cuando no hay viento.

Why is viento singular and not vientos?

In Spanish, as in English, viento is normally used in the singular when referring to wind as a general weather phenomenon:

Hay viento. – “There is wind / It’s windy.”
No hay viento.

The plural vientos is possible but more literary or specific, for particular types or directions of wind:

Los vientos del norte son fríos. – “The northern winds are cold.”

In your sentence, we’re just talking about wind in general, so singular is the natural choice.

Could I say la temperatura se sube instead of la temperatura sube?

No; here the reflexive se is not used.

La temperatura sube un poco.
→ “The temperature rises/goes up a bit.” (intransitive verb, no se)

You might see subirse in other meanings, for example:

Subirse al tren – to get on the train.
Se me subió la fiebre. (colloquial, in some regions) – “My fever went up on me.”

But for la temperatura as the grammatical subject rising by itself, standard Spanish uses subir without se:

La temperatura baja. – “The temperature goes down.”
La temperatura sube. – “The temperature goes up.”

What’s the difference between un poco, un poco de, and poco in la temperatura sube un poco?

Here, un poco means “a little / a bit” and modifies the verb sube:

La temperatura sube un poco.
→ “The temperature goes up a bit.”

Common distinctions:

un poco
- verb/adjective
  - Estoy un poco cansado. – “I’m a bit tired.”
  - La temperatura sube un poco. – “It goes up a bit.”
un poco de
- noun
  - Quiero un poco de agua. – “I want a little (bit of) water.”
poco / poca / pocos / pocas (without un) often means “not much / not many” (scarcity):
- La temperatura sube poco.
  → “The temperature doesn’t rise much.” (more like “hardly rises”)

So un poco is neutral and just means “a small amount”; poco alone can sound like “not much” / “barely”.

Is it normal to use tranquila for snow? Isn’t tranquilo more for people?

Tranquilo / tranquila is very commonly used for people, but it can also describe:

Places:
- Un pueblo tranquilo – a quiet town
- Una calle tranquila – a calm street
Situations / environments:
- Un ambiente tranquilo
Natural scenes:
- El mar está tranquilo. – The sea is calm.

Using tranquila for la nieve is metaphorical but perfectly natural: it suggests that nothing is moving, no blowing, no swirling — a calm, still appearance. Synonyms you might also see:

la nieve parece más calma
la nieve parece más quieta

But tranquila is very idiomatic and easy to understand.