Hi, Nancy. Shanghai, Hangzhou and Suzhou are similar in weather. They are close to each other and In March, the weather is getting warm. The temperature is about 10-15C. However, it is changeable. It will be cold if it is rainy. I came there this March and it is rainy days. You should wear thin sweater and a coat. Beijing in March is windy and the average temperature of this month is about 5C. Hope it helps.