Method — the best window

How the best window is chosen

Other apps print “Best Time 6 PM” with no reason attached — a bare claim about when animals move, from a formula you cannot see. Our daily window is a different kind of statement: it is the stretch of the day when your conditions hold — when the thermal is doing one thing, the wind holds a direction, and your scent stays off the bearing you set. Every clause in the reason line is a fact we computed, and none of them is a claim about animal behaviour.

The scoring

for each forecast hour of the day (terrain-corrected wind):
  reversal in progress ......... excluded outright
  scent reaches your bearing ... excluded outright
  scent stays off your bearing . +3
  stable thermal (drain/rise) .. +2   (no bearing set)
  wind-driven hour ............. +1   (no bearing set)
  sustained wind > ~18 mph ..... −1
  precip chance ≥ 50% .......... −1

window = the contiguous run with the highest mean score
         (ties: longer, then earlier), clamped to legal light

The per-hour inputs are the same terrain-corrected wind the thermal model computes for the hourly strip and the wind calendar — ambient forecast plus the slope’s own flow, judged against your approach bearing by the same scent-cone geometry. A short clearly-good window beats a long mediocre one on purpose: the number a hunter plans around should be the strongest claim we can defend. On a day where every huntable hour is a reversal or has your scent on the animal, the answer is no window, said plainly — not a forced pick.

No dawn bias

We deliberately apply no dawn/dusk weighting. When the window lands at first light it is because drainage genuinely holds a defensible scent picture there — cold air running downslope in one direction for hours — not because we assumed animals move at dawn. That keeps this feature honest about what it knows: air, never animals.

Legal light

Where the state’s big-game shooting-hours rule is verified — every covered state ships a rule row carrying the regulation’s verbatim sentence, its official source link and the season it covers — the window is clamped to that legal span, which is why its edges can land at times like 6:10. Arizona is the outlier: daylight-only, no half-hour extensions. Several states adopt their own printed sunrise/sunset tables as the official times; their computed values carry a “the state’s tables govern” caveat on the day’s legal-light line. A state we have not verified gets no legal claim at all — the window is then bounded to daylight for usefulness, and no “legal light” label appears. Scope is deer/elk/pronghorn-class big game: turkey and waterfowl hours differ and must come from the regulations.

Confidence

A window five days out inherits the forecast’s uncertainty. Each day samples the NBM ensemble spread at the point; when the models disagree, the window renders muted with a “treat loosely” note instead of pretending a guess is a promise. No competitor shows this error bar at all.

Limits, stated plainly

• The thermal model’s reversal timing carries its measured ±75-minute error — window edges adjacent to a flip inherit it.
• The forecast is a ~2.5 km model cell corrected for your slope; a spot under cliff bands or in a slot canyon deviates further than the correction can know.
• Without an approach bearing the score falls back to thermal stability alone — set the bearing to make the verdict about your animal.
• Legal times are computed from solar geometry. In table-authoritative states, confirm against the state’s published table before you shoot.

Open the map and tap any point to see the week’s windows for that ground.