Learn French: En janvier, il fait très froid. - In January, it is very cold.

In French, we use the verb faire (to do or make) to talk about the weather, not être (to be). So, il fait froid literally translates to "it makes cold," but it is the standard way to say "it is cold."

Why isn't janvier capitalized here?

In French, the names of months (like janvier, février) and days of the week are not capitalized unless they appear at the very beginning of a sentence.

Why do we use en before janvier?

The word en is the preposition you must use to say "in" when talking about months. You will use this same word before all other months, like en février (in February) or en mars (in March).

Does il mean "he" in this sentence?

No, here il means "it." Just like in English when we say "it is cold," the "it" doesn't refer to a specific person or object. French always uses il for general weather expressions like this one.