is the weather "gay" or "muggy"?

A few days ago, I went for a walk around the park and soon felt sweaty. It was very "hot and humid" and I had difficulty remembering what the German word for it was. Was it "schwul" or "schwül"? Note that the different between the two words is one umlaut (the two dots above the u). 

Now, I knew one meant "hot and humid" (or "muggy") and the other meant "gay" (as in homosexual) and I wracked my brain to remember the mnemonic (Eselsbrücke) for the words.

And then it came to me: schwül macht müde. Muggy makes [you] tired. Both adjectives have an u with an umlaut in them.

German can be a minefield at times. Just two small dots can make such a difference in meaning.