Solunar Windows (Baseline) — Research & Methodology
Last updated: 2026-02-15
This page documents the Solunar Windows (Baseline) profile: classic solunar timing only (Major/Minor windows, dawn/dusk overlap, moon phase curve). Best for freshwater when your species isn't listed (e.g. bass, crappie, bluegill). It is not species-verified.
Below: the variables we use, open-access citations with verbatim quotes (and page pointers), and what is research-backed vs calibrated. We do not publish proprietary weights, caps, or equations so our ratings remain our own.
How it works (overview)
Baseline is a Major + Minor window rating: each solunar window gets a 1.0–5.0 score, and the day score is the duration-weighted average of all window scores.
We combine three kinds of input: moon position (overhead/underfoot vs rise/set), moon phase (smooth curve: gibbous higher, quarter lower), and dawn/dusk overlap (fraction of the window inside civil twilight). Research chooses the drivers; we calibrate their relative importance and how they map onto 1.0–5.0 so the scale is stable and no single input dominates.
Major vs Minor: Shaw et al. 2021 show that moon overhead/underfoot is associated with higher success than when neither event occurs. We treat Major windows as always a lift (we do not map the worst Major down to 1.0). Moonrise/moonset (Minor) has less direct evidence; we keep Minor ratings conservative so we never present them as equivalent to the best Major conditions. Exact scale endpoints and caps are proprietary.
Variables (what's research-backed vs calibrated)
Research-backed = driver/pattern supported by open-access source with quote. Calibrated = we chose the exact value/cap for a stable 1–5 score; direction may still match literature.
Moon position — Major
Research-backed: ~10–12% higher success when moon overhead/underfoot.
Source (open access): Shaw et al. 2021 — PLOS ONE
"Anglers were observed to be about 10–12% more likely to be successful when the moon was overhead or underfoot during their trip rather than when neither lunar event occurred during an angling event (Fig 2D)."
(PDF p.13)
Moon position — Minor
Calibrated: Moonrise/moonset has less direct evidence than overhead/underfoot; we weight it conservatively relative to Major.
Moon phase
Calibrated (direction from Shaw): Gibbous highest, quarter lowest in source; we use a smooth phase curve so moon phase is the dominant driver over twilight overlap. Exact curve shape and magnitude are proprietary.
Source (open access): Shaw et al. 2021 — PDF (printable)
"The odds of a successful trip were highest during the gibbous phases… and lowest during the quarter phases…"
(PDF p.13)
Dawn/dusk overlap
Calibrated (direction from Shaw): Lower solar intensity → higher success; we use civil twilight overlap as proxy. We keep twilight secondary to phase; exact magnitude is proprietary.
Source (open access): Shaw et al. 2021 — PDF (printable)
"Mean daily solar radiation had a negative effect on walleye trip success… The observed percent of successful trips tended to increase with decreasing solar intensity …"
(PDF p.11)
Window-scale calibration
Evidence-backed + calibrated: Major floor from Shaw 2021 (Major always a lift vs no event). Minor ceiling by caution (no evidence Minor = best). Exact mapping from combined lift to 1.0–5.0 is proprietary.
Major quarter cap
Calibrated (trust rule; not a biological claim): If moon phase is in the quarter band (near 1st/3rd quarter), we cap Major window ratings so quarter-phase windows are not shown as "near-perfect" due to overlap alone. Exact cap is proprietary.
Key definitions & verification sources
Civil twilight (overlap window)
Used for: Defining when a solunar window "overlaps" dawn/dusk (overlap_fraction).
Source (open access): NWS/NOAA — Twilight definitions
"Morning civil twilight begins when the geometric center of the sun is 6 degrees below the horizon, and ends at sunrise. Evening civil twilight begins at sunset, and ends when the geometric center of the sun is 6 degrees below the horizon."