What about 10th May visit Taipei? any bad weather? My first time there.

At present, it is hard to tell the exact weather on that day, but only some general information can be told based on the previous records.
Usually, in the early May, the average temperature is around 20 to 25C. It may rain a lot even in the first week, so humid will accompany you during your traveling.
So the rain gear and sun glasses are suggested to take.

Thanks Andrew. Raining season there so if i buy any rain gear there much easier than bring along? going uphill would b risky too, right?

Yes, it will be convenient to buy rainy gear upon your arrival. Also you may fortunately meet several cloudy days during that period, when it shall be fine and secure to climb the hill/mountain. Therefore, you are recommended to check ahead the weather forecast before leaving!