Understanding ADS-B Weather (FIS-B)

Understanding ADS-B Weather (FIS-B)

Understanding ADS-B Weather (FIS-B)

Stratux gives you free weather — no subscription needed. Here’s how it works.

What is FIS-B?

FIS-B (Flight Information Service - Broadcast) is weather and aeronautical data the FAA broadcasts from its 978 MHz ground network. It’s completely free.

What You Get

Product Description Update Rate
NEXRAD Composite radar imagery ~5 minutes
METARs Current airport conditions When issued
TAFs Terminal forecasts When issued
TFRs Temporary Flight Restrictions When issued
NOTAMs Notices to Airmen When issued
Winds Aloft Wind forecasts by altitude 6 hours
PIREPs Pilot reports When filed

Why It’s Free

The FAA broadcasts this data as part of the ADS-B ground infrastructure. They’re already sending traffic info, so they include weather too. No subscription, no activation, no account needed.

This is the same data you’d pay $50-100/month for from other services.

Why Don’t I See Weather on the Ground?

The 978 MHz ground towers are line-of-sight. On the ground, terrain, buildings, and hangars block the signal.

Typical experience: - Ground: No weather (or spotty) - 500 feet AGL: Starting to see data - 1,000+ feet AGL: Full weather coverage

This is normal. The system was designed for aircraft in flight, not on the ramp.

Weather Latency

FIS-B weather has some delay built in:

Product Age When Received
NEXRAD 5-15 minutes old
METARs Usually current
TAFs Usually current

Important: Never use ADS-B weather for tactical maneuvering around thunderstorms. The radar image is several minutes old. Use it for strategic planning and situational awareness.

Stratux Doesn’t Show Weather

Stratux itself has no display — it’s a receiver. Weather data flows to your EFB app (ForeFlight, Avare, FlyQ, etc.).

To see weather: 1. Ensure your EFB is connected to Stratux WiFi 2. Enable weather layers in your app 3. Be at altitude for FIS-B reception

Checking FIS-B Reception

Visit http://192.168.10.1 while connected to Stratux. The status page shows: - FIS-B messages received - 978 MHz signal activity - Weather products decoded

If you see 978 MHz activity but no weather in your app, check your app’s weather layer settings.

Coverage Gaps

FIS-B coverage isn’t 100% everywhere: - Rural areas may have weaker coverage - Valleys and terrain can block signals - Very low altitudes are more affected

Tower coverage map →


Weather not showing? See Troubleshooting Weather.

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