I have sent money home every month for the last 2 1/2 years and it doesn't seem there's a particular day of the month or month of the year that's always better. What I do is sign up for a daily email on the exchange rate so that I know if it's in a dip or surge lately. That way I know if I should wait a week or try to transfer extra or something. The rate has been stuck at around 88 cents to 1000won this year. For instance, things like situations with North Korea make the exchange rate temporarily worsen. Last week the exchange rate was worse because of the rocket launch situation, so I would have waited for a week for things to return to a more normal number.