Learn Hardcore German: Wir treffen uns im Hof, sofern es nicht regnet. - We will meet in the courtyard, provided it does not rain.

It means provided (that) or as long as. The sentence says the meeting in the courtyard will take place only under the condition that it doesn’t rain. In English you could paraphrase it as: “We’ll meet in the courtyard, provided it doesn’t rain.”

How does sofern compare to wenn, falls, and es sei denn?

sofern = “provided that,” slightly formal/restrictive: Wir treffen uns im Hof, sofern es nicht regnet.
wenn = neutral “if/when”: Wir treffen uns im Hof, wenn es nicht regnet. (Same meaning here.)
falls = “in case/if,” often used for possible scenarios: Wir treffen uns im Hof, falls es nicht regnet.
es sei denn = “unless,” introduces an exception and is structured differently: Wir treffen uns im Hof, es sei denn, es regnet.
Note: sofern (nicht) and es sei denn can be truth-conditionally equivalent in many contexts, but you cannot swap them word-for-word; the structure changes.

Why is the verb at the end in sofern es nicht regnet?

Because sofern introduces a subordinate clause, and in German subordinate clauses the finite verb goes to the end: … sofern es nicht regnet. In a main clause you’d say: Es regnet nicht.

Is the comma before sofern required?

Yes. Subordinate clauses introduced by conjunctions like sofern, wenn, weil, etc., are separated by a comma: Wir treffen uns im Hof, sofern es nicht regnet.

Why is it wir treffen uns and not just wir treffen?

sich treffen is a reciprocal verb meaning “to meet (each other).”

Wir treffen uns = We meet each other (we have a meeting).
Wir treffen Paul = We meet Paul (direct object is someone else, not reciprocal).
The reflexive pronoun is needed to express the reciprocal meaning.

What case is uns in, and why?

uns here is the accusative reflexive pronoun for the 1st person plural. treffen takes an accusative object; in the reciprocal use (sich treffen), the reflexive pronoun is in the accusative: ich mich, du dich, er/sie/es sich, wir uns, ihr euch, sie/Sie sich.

What does im stand for in im Hof?

im is the contracted form of in dem. Because this is a static location (“in the courtyard”), in takes the dative: in dem Hof → im Hof. If it were motion toward the courtyard, you’d use accusative: in den Hof (into the courtyard).

Should it be im Hof or auf dem Hof?

Both exist, but they differ by context:

im Hof = inside an enclosed courtyard (courtyard of a building block), literally “in the courtyard.”
auf dem Hof = on a yard or farm premises; also common for schoolyards (auf dem Schulhof).
So pick the one that matches the setting.

Can I start the sentence with the condition?

Yes: Sofern es nicht regnet, treffen wir uns im Hof.
When a subordinate clause comes first, the finite verb of the following main clause still occupies the second position: …, treffen wir uns …

Why is the present tense used for a future plan?

German commonly uses the present tense for scheduled or planned future events: Wir treffen uns … means “We’ll meet …” in this context. Werden-future (Wir werden uns treffen …) is possible but not necessary and can sound more formal or emphatic.

Can I drop the es in sofern es nicht regnet?

No, not in standard prose. Weather verbs like regnen require the dummy subject es. Colloquially you might hear contractions like sofern’s (for sofern es), but you don’t omit the subject entirely in writing.

Why is it nicht regnet here but Es regnet nicht in a main clause?

Placement of nicht depends on clause type and focus:

Subordinate clause with a simple verb: … dass es nicht regnet (nicht directly precedes the verb at the end).
Main clause: Es regnet nicht.
Both negate the verb “to rain,” just with different word order due to clause structure.

Does Hof always mean “courtyard”?

No. der Hof can mean:

a courtyard (most common for im Hof),
a farmyard (auf dem Hof),
a royal court (am Hof).
It does not normally mean a court of law (that’s das Gericht, though names like Bundesgerichtshof contain Hof historically). Context decides the meaning.