For the US version, they usually film in the late summer or early fall. Think August or September. Why? So the Scottish highlands look appropriately moody and the castles haven’t frozen over yet.
The UK version? They shoot in spring, around March or April. Because even traitors need decent weather for their dramatic cloak walks. But here’s the kicker: they film it in just 12 to 14 days. That’s it. Two weeks to forge alliances, weep over round tables, and accuse your new best friend of being a murderer.