Please check what travel documents you need before travelling to Korea or any other countries on your trip. Presently, Canadian passport holders do not require a visa for the entry purpose of a short term visit up to 180 days. However, you may have to apply for the Korea Electronic Travel Authorization (K-ETA) and pay an application fee of 10,000 KRW (approx. 10 CAD) if the temporary exemption of K-ETA for Canada is not extended beyond December 31, 2025.
In Seoul, the average weather in January ranges from 1 °C to -6 °C and can drop below -10 °C. Bring your parka and thermal underwear.
Attires for weddings in Korea are the same as in Canada. The dress code for the wedding is cocktail/semi-formal winter aesthetics - moodboard link: https://pin.it/3ZZtHCTdt