what will the weather be like from 11june-20june in Taipei? Any idea??

It will be a little hard, with the average temp of 28C or around. Rain will frequently happen at that time, most light rain and sometimes heavy rain or thuderstorm. It will start to turn into typhoon season, so you'd better pay close attention to weather report. Both long-sleeved and short-sleeved shirt, shorts, regular jeans and a light jacket will help. Oh, and umbrella or other rainy gear shall be necessary.