Learn French: J'ai acheté des gants pour la neige. - I bought some gloves for the snow.

The word pendant is only used when 'for' refers to a length of time or duration (like 'for three days'). In this sentence, 'for' means 'intended for' or 'for the purpose of' the snow. Whenever 'for' shows purpose, use, or destination, French always uses pour.

Why do we say pour la neige instead of just pour neige?

In English, we can leave out the article and just say 'for snow'. However, French nouns almost always require an article. Because we are talking about snow as a general concept or category, and neige is a feminine word, we must use the definite article la.

Could I say J'ai acheté les gants instead of des gants?

You could, but it changes the meaning slightly. Using des gants means you bought 'some' gloves (an unspecified pair). If you use les gants, it means you bought 'the' gloves (a specific pair that you and the person you are talking to already know about).

Why is the past tense J'ai acheté used here rather than the imperfect tense (j'achetais)?

Buying the gloves was a single, completed action in the past, which is exactly what the passé composé (J'ai acheté) is used for. You would only use the imperfect tense (j'achetais) if you were describing an ongoing past habit or setting a scene, like 'I used to buy gloves every winter'.