For people who rely on insulin to manage their diabetes, keeping their insulin at the right temperature is an important part of everyday life. But insulin can be exposed to heat, cold, or physical stress during travel, at home, outdoors, or while being transported. As the world gets warmer, these challenges are becoming increasingly important - particularly for people living in hot climates or places where reliable refrigeration is not always available. Our review explores what happens to insulin when it is exposed to temperatures outside the recommended range. Although we know from laboratory studies that temperature can affect insulin, we still have much to learn about what happens in real-life situations. Better understanding of these effects will help people with diabetes store and use their insulin safely, improve guidance, and support access to effective insulin in a changing climate.