hi...I plan to go to taiwan on 17th oct to 23 oct...will the weather be good?

Which area do you refer to? The northern, central or southern areas? Anyway, Taipei will be cloudy with the average temp of 25C then. Sometimes, it may shower, so you may need to prepare simple rainy gear.

The sunny days in Taichung will be the majority. The temp ranges from 20C to 28C, so it will be pleasant to travel then.

Tainan shall be a little warmer than Taipei. Rainy days will also happen from time to time (just lightly rain).