Hot temperatures: The mean average temperature in Thailand is 27.7°C with temperatures rising to 35 °C in April. Mean relative humidity for an average year is 79.9%. Shrimp farm workers in pond areas are at risk of heat stroke, heat exhaustion, heat cramps, and heat rash, which in extreme cases can result in death. Whilst workers need to drink to avoid dehydration, excessive water consumption is harmful (not more than 13 litres in a 24 hour period) [1].