Weather in Seoul and Jeju Island (Late June)

Hi all,

Hope you can help and apologies in advance if this question has already been answered.

I am thinking of going to South Korea with friends from the 18th till 28th of June 2009 and was wondering if you know what the weather will be like in Seoul and Jeju Island around that time.

Also, as none of us have been before. How many days would you recommend we stay at each location and what are the must do%26#39;s? (we are all in our late 20s - 4 girls, 2 guys). Are there any other locations you think we should/could visit within our time frame?

Finally, would you happen to know if there are any outdoor hot springs in the snow that we can visit?

Thanks a lot all!