Experiencing headaches and vomiting when the temperature rises above 35?C is often related to heat sensitivity, most commonly mild heat exhaustion or dehydration, where your body struggles to cope with high temperatures, leading to symptoms like headache, nausea, weakness, and sometimes dizziness. In some people, heat can also trigger migraines. To prevent this, try to stay well hydrated (drink water regularly, even before you feel thirsty), avoid going out during peak heat hours, wear light and loose clothing, use cooling methods like fans or shade, and take frequent breaks if you must be outdoors. Eating light meals and including fluids like oral rehydration solution or coconut water can also help maintain electrolyte balance. If symptoms become severe, occur even with mild heat exposure, or are associated with confusion, fainting, or very high body temperature, seek medical attention promptly, as more serious heat-related illness may need treatment.