Planning to visit Beijing and Shanghai early April, What sort of weather can i expect?

Accoring to the previous statistics, during that period of time, the temperature in BJ is 46.4 F to 75.2 F. It's cool and comfortable. You need to bring your light jackets in order to adapt large temperature difference.
In Shanghai, the temperature is 53.6 F to 69.8 F. T-shirts and jeans are enough for you to prepare.

BEIJING: Spring and mild weather come to Beijing in April, which is much warmer and more pleasant than March. Various flowers are in full bloom, and trees are gradually turning green. The temperature rises continuously day by day and may climbs up to 20C (68 F) during a warm afternoon. There are large differencec between day and night temperatures. The weather is still dry and windy, with occasional sandstorms. There may be light rain, which won’t last long. The temperature won’t drop too much because of the rain.

SHANGHAI: In April in Shanghai, sunny spring days are common. The day-time weather is very warm, but the temperature range in a day is large - it is much cooler in the morning and night. Light rain occurs from time to time. The color of spring has splashed every inch of the land and all things are reinvigorated.