OSHA-NIOSH Heat Safety Tool is from the Centers for Disease Control and Prevention. This one helps you take precautions against outdoor heat while working or playing. It features a real-time heat index and hourly forecast specific to your location. The app is free for iOS and Android.
The Waterlogged app makes sure you stay hydrated. The app tracks your water intake with minimal effort and can send reminders of when it’s time to drink water. The app is free for iOS and Android, with in-app purchases for premium features.
EPA’s Sunwise UV Index app provides a daily and hourly forecast of the expected intensity of ultraviolet (UV) radiation. It also provides safety tips to help you plan your outdoor activities. The app is free for iOS and Android.