The weather of both cities are fine without rainfall. And, the temperature is about 15~20C. However, since the weather is changeful in this season, please refer to the real-time weather forecast before leaving.

From downtown Shenzhen, you could take a bus to arrive in Hong Kong directly. Or, you could take a city-bus from downtown Shenzhen to Luohu border, walk through which you could take a train or city-bus to arrive in downtown HK easily.