An owner planning a weekend away usually starts with the same chore: open the forecast for each airport, read it day by day, work out the crosswind, and then do it again for the trip home. A good day to go isn't much use if the return leg lands in a front two days later.
Flight Window, a tool added to Hangar Flying on Nov. 1, does that comparison across a whole week. Hangar Flying shares an owner with Hangar Debrief. The tool needs no account.
What goes in
A pilot enters the two ends of the trip, the leave and return dates, and a tail number. The ends can be airport identifiers, or latitude and longitude for an off-airport site, which suits a backcountry strip. Looking up the tail number fills in typical cruise speed, fuel burn, usable fuel, and takeoff and landing distances over a 50-foot obstacle.
Those are typical numbers, and the tool says to check them against the POH. That matters most for a homebuilt, where two airplanes of the same model may not perform alike. The numbers can be typed in by hand, so a builder can use the figures from the airplane's own flight testing.
What comes out
Hangar Debrief ran one trip on the morning of Nov. 2: Centennial (KAPA) to Santa Fe (KSAF) and back, two nights away, with numbers typed in for a four-seat trainer at 140 knots and 9 gallons an hour, with 42 gallons usable. Flight Window kept the two-night stay and tried it from every departure date in the forecast:
- Better: Tuesday, Nov. 3; Thursday, Nov. 5; Friday, Nov. 6; and Saturday, Nov. 7.
- Possible: Wednesday, Nov. 4.
- Poor: Monday, Nov. 2.
- Too far out: Sunday, Nov. 8, and Monday, Nov. 9. The forecast ended Nov. 9, so those stays would have come home past the end of it.
The ratings compare the dates in one trip against each other. They aren't a grade on the weather itself, so a "Better" day isn't a promise of a good one. Something true of nearly every date, such as a short runway, is listed once and doesn't lower any day's rating. Density altitude doesn't count against a day on its own either. It shows up in the takeoff and landing distances instead.
Picking a date opens every check behind the rating. For the Friday outbound leg, the tool showed a 12,500-foot cruise on the VFR hemispheric rule, with terrain sampled up to about 8,944 feet, and 9:00 to 10:51 a.m. for the 245 nautical miles. It figured about 19 gallons, plus 7 for a 45-minute reserve, against the 42 on board.
The most useful lines for that trip were the runway ones. A trainer entered with a 1,500-foot takeoff needed about 2,607 feet over 50 feet at Centennial's 6,276-foot density altitude. The tool multiplied that by 1.5 for margin and set the result against the runway's 10,001 feet. Santa Fe's landing line came to about 1,651 feet at 7,534 feet density altitude.
The rest of the page lists surface wind and crosswind by runway, ceiling and visibility, enroute weather, daylight at arrival, obstacles near the runway and the airport's remarks. For the stay it lists forecast severe weather, tie-downs, hangars and the fuel on the field. Hangar Flying says TFRs are checked as well.
Each line shows the limit it was judged against. On this run those were a 3,000-foot ceiling, 5 miles visibility, 20 knots sustained, 25 knots gusting and a 12-knot crosswind. A pilot with different personal minimums should read the lines with those in mind, not only the rating.
What it doesn't do
The instructions are plain about the gaps. NOTAMs, winds aloft and smoke aren't checked yet. Times and fuel assume no wind aloft, so the 19 gallons above could be well off on a day with a real headwind over the mountains. The freezing level is estimated from the surface temperature.
The forecast comes from the National Weather Service, using TAFs and MOS for the first few days. Beyond that, the instructions say to treat it as a trend. A date six days out can change rating by the next morning, so it's worth running the trip again as the day gets closer.
None of this replaces preflight action. 14 CFR 91.103 requires each pilot in command to become familiar with all available information concerning the flight, and for a flight away from the vicinity of an airport that includes weather reports and forecasts, fuel requirements and alternatives. Flight Window says it isn't an official briefing and points pilots to a standard briefing at 1800wxbrief.com. It's a way to pick which days are worth briefing.
Sources: Hangar Flying, Flight Window, run Nov. 2, 2026; Flight Window instructions; Hangar Flying, What's new; 14 CFR 91.103.
Photo: Embry Riddle Cessna 172 by Quintin Soloviev, CC BY 4.0, via Wikimedia Commons.