1.According to Ayurveda curd consumption at night is not good as it causes mucus (kapha)development which leads to cough and cold.
2.Add sugar in curd if you having it during the day and if you are eating curd at night, add sugar or black pepper. It will help in digestion.
3.Buttermilk is best substitute to curds at night.
4.Curd rice is very good for the stomach and a light option for the summers too.