Unbranded steel cooker hood with metal chimney going up to the roof (bungalow).
On a few days a year, when the wind is in a certain direction, there's a cold spot in the kitchen. It's cold air dropping from the cooker hood. The solution is to turn the extractor fan on to its lowest speed setting. There's a faint whirring and the cold spot completely disappears within a few minutes and the whole kitchen warms right up. The fan is just enough to push the cold air back up and away.
You'd think there's be a lever or something to close a baffle within the hood but I havent' found it.