Know when to fish, and what to tie on.

Hatch Window pulls the conditions that matter — solunar peaks, weather, and seasonal hatches — into one screen so you plan the day around when fish actually move.

Hatch Window · an app by Baker Ventures LLC

What it does

Solunar peaks at a glance.See the major and minor feeding windows for your day and location so you fish the hours that count.
Conditions that drive the bite.Live streamflow and gauge height from USGS, plus temperature, wind and cloud cover for the day, all in one place.
Hatch guidance by season.Get a read on what's likely hatching for the time of year, so you head out with the right flies instead of guessing at the fly shop.
Plan around your spot.Set the water you're fishing and see its window and conditions, then plan the drive around the best hours.
Log the day.Keep a simple record of when and what worked, so your own history becomes the best forecast next season.

How it works

  1. Pick your spot and day.
  2. Read the window — solunar peaks, weather, and the seasonal hatch picture together.
  3. Fish it and log it, building your own record of what worked.

Questions

Where does the conditions data come from?
Hatch Window combines publicly available weather and streamflow data — the USGS Water Services API — with solunar math and seasonal hatch references. It's attributed in the app, and we never show a made-up number.
Will it tell me exactly what fly to use right now?
It gives seasonal hatch guidance to narrow your choices — a starting point informed by the calendar and your water, not a live report of what's on the water this minute.
Is solunar a guarantee fish will bite?
No. Solunar windows indicate likely feeding activity; fishing depends on many factors and no forecast guarantees a catch.
Does it work without cell service on the river?
Your saved spots, catch log, times, and flies work offline. Live conditions need a connection to fetch fresh USGS data, so grab a look before you lose signal.
Does it track my location?
Location is used to give you local conditions and windows. See the privacy policy for how it's handled.
Is there a fee?
No. Hatch Window is free and every feature ships unlocked. There is no subscription, no in-app purchase and no ads.
Please note. Conditions and feeding windows are estimates built from public data plus solunar math and a curated hatch list. They are a starting point, not a promise — rivers and fish don't read the forecast. Always check current local flow and weather yourself, follow your state's fishing regulations and access rules, and put safety first on the water. Hatch Window doesn't track your license or local rules; confirm them with your state agency before you fish.

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