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River Difficult Run (Virginia) — one of the area's fishing spots. About 1 km long. Nearby towns: Fairfax and Arlington. This page shows an hourly bite forecast for today and the week ahead; the algorithm factors in the weather, atmospheric pressure, and the moon phase.
Partly cloudy: 63–93 °F
The bite is strong — fish are active. Pressure is dropping — this usually boosts the bite.
Best time — 06:00–08:00 (dawn bite) and 19:00–21:00 (dusk bite).
Work the cover — snags, weed edges, hole entrances; retrieve the lure with pauses.
In clear water, natural colors work best: small jig or minnow bait.
It's a hot day — a hat, sunglasses, and plenty of water are a must.
Worth going — it's a productive day.
The computed water temperature is around 71 °F — inside the 57–75 °F comfort range for Black crappie, so baseline activity is high.
Black crappie works the twilight: the peaks are pinned to sunrise and sunset — their times are in the sun-and-moon card above.
Pressure is dropping 0.24 inHg over the day — fish are usually more active ahead of a weather change.
One more input — the moon's feeding windows: within their hours the score sits higher than across the rest of the day. The window times are in the “Solunar feeding periods” card below.
September is an active season for Black crappie here.
These are the same values the bite curve above was computed from. How the forecast works
Partly cloudy · feels like +87°
The day is 2 min shorter than yesterday.
Sunshine hours count direct sun only — cloud cover cuts it, so it is shorter than daylight.
The windows are set by the moon's transit and rise, and the forecast above already accounts for them: within these hours the bite score sits higher than across the rest of the day, while the day's overall level still comes from the catch-calibrated model.
What are solunar periods?Measured river conditions are available for Difficult Run: current gauge height, streamflow, and water temperature when reported by the source.
USGS gauge DIFFICULT RUN NEAR GREAT FALLS, VA, 0.3 mi away · measured 2026-09-04 14:15 · data source · provisional data, subject to revision