Flight Window takes a round trip and compares every departure date in the forecast, about seven days, so you can pick the better ones. It needs no account. It is not a briefing: the pilot in command decides, and a standard briefing still comes first.
To find the best dates:
- Press Tools in the bar at the top of any page, then Flight Window.
- Enter From and To: an airport identifier, or a latitude and longitude for an off-airport site.
- Choose Leave. Return starts on the same date; change it to the day you will fly back.
- Enter your tail number and press Look up. The page names the aircraft and fills in its typical numbers under Your aircraft’s numbers. Check them against your POH and change any that differ.
- Press Find the best dates. The best dates come first, then every departure date rated Better, Possible or Poor.
- Press any date to see its legs, the stay and every check.
A rating compares the dates of this trip with each other. What is true on nearly every date, such as a short runway for this aircraft, is listed once under On any of these dates and counts against no day. Density altitude counts against no day by itself; its effect is in the takeoff and landing distances.
Not checked yet: NOTAMs, winds aloft and smoke. Times and fuel assume no wind aloft, and the freezing level is estimated from the surface temperature. The forecast comes from NOAA’s National Weather Service, with TAFs and MOS for the first days; further out, treat it as a trend.