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Spawn timing & temperature guide

Southern Flounder spawn timing guide.

Paralichthys lethostigmaInshore SaltwaterBroadcast spawnerAgency-reported

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.

Southern Flounder 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.

32°37°42°47°52°57°62°67°72°77°82°87°Peak 62–66°F
Pre-spawn — best fishingPeak spawn — conservationPost-spawn — recovery feeding·Dashed line = peak spawn boundaries

Southern Flounder spawn cycle

Pre-Spawn
65–59°F
Trophy fishing
Spawn
59–70°F (peak 62–66°F)
Conservation window
Post-Spawn
70–78°F (~21 days)
Recovery feeding
Summer Pattern
Above 78°F
Standard summer patterns

Phase-by-phase breakdown

Pre-Spawn

Trophy fishing window
65–59°F

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.

Spawn

Conservation window
59–70°F (peak 62–66°F)

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

Recovery feeding
70–78°F (~21 days)

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.

Summer Pattern

Standard patterns
Above 78°F

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.

  • North Carolina Outer BanksOctober – November

    Outer Banks fall flounder run is the most concentrated event of the year — coincides with NC spawn closure.

    JanJan — Outside spawn windowFebFeb — Outside spawn windowMarMar — Outside spawn windowAprApr — Outside spawn windowMayMay — Outside spawn windowJunJun — Outside spawn windowJulJul — Outside spawn windowAugAug — Outside spawn windowSepSep — Pre-spawn — water rising toward 59°FOctOct — Peak spawn (62–66°F)NovNov — Peak spawn (62–66°F)DecDec — Post-spawn — water at 70°F+
    Typical window: October – November
  • North Carolina Southern CoastOctober – November

    Cape Fear region fall flounder run.

    JanJan — Outside spawn windowFebFeb — Outside spawn windowMarMar — Outside spawn windowAprApr — Outside spawn windowMayMay — Outside spawn windowJunJun — Outside spawn windowJulJul — Outside spawn windowAugAug — Outside spawn windowSepSep — Pre-spawn — water rising toward 59°FOctOct — Peak spawn (62–66°F)NovNov — Peak spawn (62–66°F)DecDec — Post-spawn — water at 70°F+
    Typical window: October – November
  • South Carolina LowcountryOctober – November

    Lowcountry SC fall flounder migration.

    JanJan — Outside spawn windowFebFeb — Outside spawn windowMarMar — Outside spawn windowAprApr — Outside spawn windowMayMay — Outside spawn windowJunJun — Outside spawn windowJulJul — Outside spawn windowAugAug — Outside spawn windowSepSep — Pre-spawn — water rising toward 59°FOctOct — Peak spawn (62–66°F)NovNov — Peak spawn (62–66°F)DecDec — Post-spawn — water at 70°F+
    Typical window: October – November
  • Texas Upper CoastOctober – November

    Galveston Bay fall flounder run; Texas closure typical.

    JanJan — Outside spawn windowFebFeb — Outside spawn windowMarMar — Outside spawn windowAprApr — Outside spawn windowMayMay — Outside spawn windowJunJun — Outside spawn windowJulJul — Outside spawn windowAugAug — Outside spawn windowSepSep — Pre-spawn — water rising toward 59°FOctOct — Peak spawn (62–66°F)NovNov — Peak spawn (62–66°F)DecDec — Post-spawn — water at 70°F+
    Typical window: October – November

Spawn habitat

  • Offshore spawning grounds 30–60 miles offshore
  • Inlet staging during fall migration
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 →

Track water temp for southern flounder spawn timing.

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.

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