Decoding Guide

Weather Depiction Chart


This product depicts the hourly reports of instrument flight rules (IFR), marginal visual flight rules (MVFR), and visual flight rules (VFR) conditions.



Data Sources:

Hourly surface observations


Shaded Areas indicate IFR conditions. Areas enclosed by the green line, but not shaded, indicate marginal VFR conditions. All other areas are VFR. The number of observations used to generate the report is printed on the left side of the chart.


Wx Depict Area of marginal VFR conditions -- Ceilings between 1,000 and 3,000 ft and/or visibility between 3 and 5 miles
Wx Depict Area of IFR conditions -- Ceilings less than 1000 ft and/or visibility less than 3 miles
  Areas not enclosed indicate VFR conditions with ceilings greater than 3000 ft and visibility greater than 5 miles