Spawn timing & temperature guide
The Southern Flounder spawn cycle is driven by water temperature, not calendar date — fish initiate spawn behavior when water reaches 59°F regardless of when that happens in your region. Pre-spawn southern flounder leave inshore habitat in fall (October–November) and migrate offshore to spawn — the fall flounder run.
Spawn temperature gauge
Spawn behavior is driven by water temperature, not calendar date. The same southern flounder may spawn weeks earlier in southern range than northern — track water temp, not the date.
Spawn cycle
Phase-by-phase
Pre-spawn southern flounder leave inshore habitat in fall (October–November) and migrate offshore to spawn — the fall flounder run.
The fall flounder run staging at inlets and inlet-adjacent waters is the highest-volume flounder fishing of the year — but coincides with closed seasons in NC and TX.
Active spawning behavior. Broadcast spawners offshore. Adult flounder migrate offshore to spawn after years of inshore growth.
Southern flounder are overfished in NC and parts of the Gulf — multiple states close inshore harvest during the fall spawn migration (NC October–November closure is the most prominent). C&R during the
Conservation context
Southern flounder are overfished in NC and parts of the Gulf — multiple states close inshore harvest during the fall spawn migration (NC October–November closure is the most prominent). C&R during the run is mandatory in some states.
Post-spawn flounder return inshore through winter and spring as juveniles recruit to inshore nursery areas.
Spring flounder fishing in inshore creeks and channels begins in March in the Carolinas, building through summer.
Fish disperse to summer habitat and feeding patterns. Spawn cycle complete until following year.
Standard summer fishing tactics apply.
Regional spawn windows
Southern Flounder spawn timing varies by region. Southern range fish initiate spawn first; northern fish later.
Outer Banks fall flounder run is the most concentrated event of the year — coincides with NC spawn closure.
Cape Fear region fall flounder run.
Lowcountry SC fall flounder migration.
Galveston Bay fall flounder run; Texas closure typical.
Spawn habitat
Typical depth: 60–200 ft
Male vs. female behavior
Broadcast spawners offshore. Adult flounder migrate offshore to spawn after years of inshore growth.
Closed seasons & regulations
The following states have closed seasons or restrictions for southern flounder during peak spawn:
Source
Fall flounder migration to offshore spawning documented in NCWRC and Texas Parks and Wildlife species accounts.
Source documentation →Bield: Fish ties USGS gauge data and your saved species to spawn thresholds. Get notified when southern flounder hit pre-spawn temperature in your area.
Start free trial →