May I know how shall I get to Guangzhou from Macau?

You can either take light rail or bus from Gongbei Port to Guangzhou. The train ride takes around one hour and the bus take about two hours. The temperature in mid December is around 52°F. It is a bit chilly but with a little snow. You are suggested to wear sweater and a jacket. For 3 days, you can visit Yuexiu Park, Guangxiao Si, Sun Yat-sen Memorial Hall for one day, Ancestral Temple of the Chen Family, Shamian Island, Shangxiajiu Pedestrian Street, Beijing Road and The Pearl River on the second day. If you have child, you may also spend another full day at Chimelong Tourist Resort.