Gnatcast
The biting gnat index
Free · Designed for iPad. Not verified for macOS.
Know before you go!
Gnatcast — The Biting Gnat Index
Know exactly when the no-see-ums are going to swarm.
Gnatcast is the first hyper-local forecast tool designed specifically for biting midges (no-see-ums). While regular weather apps ignore the real reasons gnats explode — low tide, calm wind, high humidity, and marsh exposure — Gnatcast combines real-time WeatherKit data, NOAA tide predictions, and live community reports to give you an accurate 0–100 Biting Gnat Index.
Perfect for coastal living in the Southeast and Gulf Coast — from Beaufort to Charleston, Savannah, Hilton Head, Tampa, and beyond.
Key Features:
• Live Biting Gnat Index (0–100) with color-coded risk level
• 72-hour hourly timeline showing exactly when swarms will peak
• 10-day daily forecast with min/max risk ranges
• Real NOAA tide integration — risk spikes hard at low tide
• Live BiteRep heatmap — see where others are currently getting swarmed
• Submit your own BiteReps to help the community
• Micro-climate adjustments for wind shielding and shade in your backyard
• Historical seasonality chart so you know what “normal” looks like
Whether you're planning a round of golf, a day at the marina, a beach walk, or just want to sit on your porch without getting eaten alive — Gnatcast tells you when it’s safe and when you need the Thermacell or DEET.
Built for the Low Country and Coastal South. Backed by real science, real tides, and real user reports.
Download now and finally stay one step ahead of the gnats.
Historical Averages fixed to prevent any 'self' data from being sent from the phone for a location other than where the user is.
The developer, Seth Stewart, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Location
- Identifiers
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Seth Stewart
- Size
- 30.6 MB
- Category
- Weather
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Gnatcast