There is no significant difference between the blood sugar of normal people in hot weather and cold weather. However, high blood sugar patients due to the body’s blood sugar regulation ability is insufficient, hot day blood sugar and cold day blood sugar is going to have a difference, often in the cold day blood sugar fluctuations slightly larger. There are many factors affecting blood glucose, mainly insulin levels in the body, diet and exercise. When the weather is cold, there is usually less exercise and the calories in the diet are often too high. At the same time, the cold will stimulate the body’s glycogen to break down into glucose, which will lead to higher blood glucose when it is cold. Diabetic patients should pay attention to keep warm in winter, hydrate in summer, pay attention to blood glucose testing, and exercise appropriately, as well as pay attention to control the dietary pattern, limiting the intake of high-fat and high-sugar foods. Patients are advised to go to the hospital for regular checkups and to conduct self-monitoring of blood glucose at home.