How it works

Water levels

Every lake page shows the latest reading from a U.S. Geological Survey (USGS) gauge on that lake. USGS publishes these readings every 15 minutes; we refresh them every few hours. Recent USGS data is provisional and can be revised.

In Oklahoma, where most reservoirs are run by the U.S. Army Corps of Engineers (USACE), the level is the hourly pool elevation the Corps' Tulsa District publishes for each lake, in feet above sea level. It is also provisional.

"Normal for this date" compares today's level with the USGS long-term daily statistics for the same gauge and calendar day: Normal means between the 25th and 75th percentile; below/above normal means outside that range; well below/above means beyond the 10th/90th percentile. For Oklahoma lakes we compute the same percentiles ourselves from the Corps' daily record for that lake (each calendar day ±7 days), once there are at least four years of data.

Percent full

Percent full comes from the Texas Water Development Board (TWDB). It is conservation storage divided by conservation capacity, so water stored in a flood pool is not counted and a lake can read 100% while still rising. TWDB updates it once a day. For a few lakes without a USGS gauge, the daily TWDB water level is also used as the lake level. In Oklahoma, percent full is the Corps' own "% of conservation pool full" figure, which works the same way.

Level history

The one-year and five-year charts use USGS daily values for the same gauge, so you can compare today's level with the same dates last year.

Weather and pressure

Hourly forecasts come from the National Weather Service for the lake's coordinates. Barometric pressure comes from the nearest NWS observation station; the trend is the change over roughly the last six hours.

Solunar times

Sun and moon times are calculated for each lake's exact location. Major periods (about 2 hours) are centered on the moon passing overhead or underfoot; minor periods (about 1 hour) on moonrise and moonset. Periods that line up with sunrise or sunset are highlighted, because many anglers find those the most productive.

The 1–10 fishing conditions score

The score starts at 5 and moves up or down with conditions anglers have long associated with fish activity:

• +1.5 within 2 days of a new or full moon (+0.7 within 4 days)
• +1 when a solunar period overlaps sunrise or sunset
• +1.5 when the barometer is falling, +0.5 when steady, −1 when rising fast
• +1 for a 5–15 mph breeze, −2 for winds above 20 mph
• −1 for a 70%+ chance of rain, −2 when thunderstorms are forecast
• +0.5 when the lake is slowly rising, −0.5 when it is dropping fast

It is an estimate of conditions, not a report of what is being caught. Local knowledge, season and water temperature matter a lot. Always put safety first and stay off the water when thunderstorms are around.