Garmin G3X Pilot's Manual page 236

Hazard Avoidance
If, for any reason, a weather product is not refreshed within the Expiration Time
intervals (see table), the data is considered expired and is removed from the display.
This ensures that only data that is consistent with FIS-B broadcast data is displayed.
If more than half of the expiration time has elapsed, the color of the product age
displayed changes to yellow. The system displays dashes instead of a product age
when a product has expired. If a weather product is not available or has not been
received, the system displays 'N/A' instead of a product age.
The table below shows the FIS-B weather expiration time and the broadcast interval.
The broadcast interval represents the interval at which FIS-B GBTs broadcast new
signals that may or may not contain new weather data. It does not represent the rate
at which weather data is updated or new content is received by the GDL 39.
FIS-B Products
NEXRAD Composite
Reflectivity (CONUS)
NEXRAD Composite
Reflectivity (Regional)
METAR
TAF
AIRMET
SIGMET
PIREP
Winds and
Temperatures Aloft
NOTAM (D)/FDC
(Including TFRs)
214
Expiration
Time
~5 minutes precipitation
60 minutes
10 minutes for clear air
60 minutes
1 minute (where available),
8 hours
As Available otherwise
12 hours
12 hours
As Available, then at 15
12 hours
minute intervals for 1 hour
8 hours
12 hours
12 hours
Weather Product Timing
Garmin G3X Pilot's Guide
Update Interval
(Minutes)
mode
As Available
8 hours
As Available
As Available
12 hours
As Available
Broadcast
Interval
(Minutes)
15
2.5
5
10
5
5
10
10
10
190-01115-00 Rev. K