Koreans crave Pajeon (korean pancake) and Makgeolli (milky Korean rice wine) on a rainy day. According to a Korean news article, sales of Pajeon ingredients actually increases on rainy days. They have a few theories on why this is true:

1. The sound of rain reminds people of the sound of making Pajeon.

2. When humidity increases, blood sugar level drops and people crave flour-based food that increases blood sugar level.

3. Makgeolli is usually paired with Pajeon. It's low in alcohol content (6%). It contains protein and vitamin B and has a sour kick to it. These characteristics make you feel like your thirst is quenched.

4. Both flour and Makgeolli contain lots of serotonin which elevates emotion and appetite. This may cheer people up when they feel down on rainy days.

Rainy or not, Pajeon is always a great snack!
See Hamul Pajeon recipe (Korean Seafood Pancake) here.

*content translated and summarized from: http://www.ebn.co.kr/news/n_view.html?id=386078