Sea surface temperature guide
Swordfish sea surface temperature guide.
- Xiphias gladius
- Billfish
- Agency-reported threshold data
Swordfish vertically migrate through the entire water column daily — deep by day, shallow by night. SST is most predictive for nighttime surface fishing; daytime deep drops focus on canyon bathymetry.
SST threshold gauge
The temperature ranges that matter.
The water temperature ranges that determine where swordfish hold and feed. Hard thresholds (dashed lines) are values outside which fish actively depart or become inactive.
Depth profile & SST reliability
Typical depth
0–2000 feet
SST as locator
Low — fish location is bathymetry-driven
Swordfish vertically migrate — deep during the day (1500–2000 feet), rising to surface at night to feed. Daytime fishing targets the deep thermocline; nighttime fishing happens at the surface where SST matters more.
Current systems & structure
Swordfish associate with deep canyon and shelf-break structure. SST is most useful for nighttime surface fishing; daytime drops are bathymetry-driven.
Best zones now
Where swordfish are in range — August.
Zones where typical August SST falls in swordfish's preferred range.
Zone-by-zone calendar
Overlap charts by zone.
For each zone where swordfish are present, the chart overlays the zone's typical monthly SST range with the species' preferred and optimal ranges. Months where the bands overlap are when fish are in range.
Northeast
Best months
June, July, August, September
| Month | Zone SST | Status |
|---|---|---|
| Jan | 40–46°F | Outside |
| Feb | 40–46°F | Outside |
| Mar | 42–48°F | Outside |
| Apr | 44–52°F | Fishable |
| May | 50–58°F | Fishable |
| Jun | 58–66°F | Peak |
| Jul | 62–70°F | Peak |
| Augnow | 64–72°F | Peak |
| Sep | 60–68°F | Peak |
| Oct | 54–62°F | Fishable |
| Nov | 48–56°F | Fishable |
| Dec | 42–50°F | Outside |
Best months
June, July, August, September
| Month | Zone SST | Status |
|---|---|---|
| Jan | 42–48°F | Outside |
| Feb | 42–48°F | Outside |
| Mar | 44–50°F | Outside |
| Apr | 46–54°F | Fishable |
| May | 52–60°F | Fishable |
| Jun | 60–68°F | Peak |
| Jul | 65–75°F | Peak |
| Augnow | 68–78°F | Peak |
| Sep | 64–72°F | Peak |
| Oct | 56–64°F | Fishable |
| Nov | 50–58°F | Fishable |
| Dec | 44–52°F | Fishable |
Mid-Atlantic
Best months
June, July, August, September, October
| Month | Zone SST | Status |
|---|---|---|
| Jan | 44–52°F | Fishable |
| Feb | 44–50°F | Outside |
| Mar | 44–52°F | Fishable |
| Apr | 46–56°F | Fishable |
| May | 54–64°F | Fishable |
| Jun | 62–72°F | Peak |
| Jul | 68–78°F | Peak |
| Augnow | 70–80°F | Peak |
| Sep | 66–74°F | Peak |
| Oct | 58–66°F | Peak |
| Nov | 52–60°F | Fishable |
| Dec | 46–54°F | Fishable |
Best months
May, June, July, August, September, October
| Month | Zone SST | Status |
|---|---|---|
| Jan | 46–54°F | Fishable |
| Feb | 46–54°F | Fishable |
| Mar | 48–56°F | Fishable |
| Apr | 50–60°F | Fishable |
| May | 56–66°F | Peak |
| Jun | 64–74°F | Peak |
| Jul | 70–80°F | Peak |
| Augnow | 72–82°F | Peak |
| Sep | 68–76°F | Peak |
| Oct | 60–68°F | Peak |
| Nov | 54–62°F | Fishable |
| Dec | 48–56°F | Fishable |
Best months
May, June, July, August, September, October
| Month | Zone SST | Status |
|---|---|---|
| Jan | 48–58°F | Fishable |
| Feb | 48–56°F | Fishable |
| Mar | 50–60°F | Fishable |
| Apr | 54–64°F | Fishable |
| May | 60–70°F | Peak |
| Jun | 68–78°F | Peak |
| Jul | 72–82°F | Peak |
| Augnow | 74–84°F | Peak |
| Sep | 70–80°F | Peak |
| Oct | 64–72°F | Peak |
| Nov | 56–64°F | Fishable |
| Dec | 50–60°F | Fishable |
Best months
January, March, April, May, June, October, November, December
| Month | Zone SST | Status |
|---|---|---|
| Jan | 58–66°F | Peak |
| Feb | 56–64°F | Fishable |
| Mar | 58–66°F | Peak |
| Apr | 64–72°F | Peak |
| May | 68–76°F | Peak |
| Jun | 74–82°F | Peak |
| Jul | 78–84°F | Fishable |
| Augnow | 78–84°F | Fishable |
| Sep | 76–82°F | Fishable |
| Oct | 70–78°F | Peak |
| Nov | 64–72°F | Peak |
| Dec | 60–68°F | Peak |
Gulf of Mexico
Best months
January, February, March, April, November, December
| Month | Zone SST | Status |
|---|---|---|
| Jan | 64–72°F | Peak |
| Feb | 64–70°F | Peak |
| Mar | 68–74°F | Peak |
| Apr | 72–78°F | Peak |
| May | 76–82°F | Fishable |
| Jun | 80–84°F | Outside |
| Jul | 82–86°F | Outside |
| Augnow | 82–86°F | Outside |
| Sep | 80–84°F | Outside |
| Oct | 76–82°F | Fishable |
| Nov | 70–78°F | Peak |
| Dec | 66–74°F | Peak |
Best months
January, February, March, April, October, November, December
| Month | Zone SST | Status |
|---|---|---|
| Jan | 64–72°F | Peak |
| Feb | 64–70°F | Peak |
| Mar | 68–74°F | Peak |
| Apr | 72–78°F | Peak |
| May | 76–82°F | Fishable |
| Jun | 80–84°F | Outside |
| Jul | 80–86°F | Outside |
| Augnow | 80–86°F | Outside |
| Sep | 78–84°F | Fishable |
| Oct | 74–82°F | Peak |
| Nov | 70–78°F | Peak |
| Dec | 66–74°F | Peak |
Conservation & regulations
ICCAT / NOAA HMS
Rebuilt — North Atlantic stock recovered. HMS permit required. Strict bag and size limits. Daytime deep-drop fishery has grown substantially in the Gulf of Mexico and Mid-Atlantic.
Stock assessment source →Daytime drops to 1500+ feet on canyon structure — bathymetry over SST. Nighttime drift fishing on the surface in 64–76°F water with squid baits. Gulf Stream edge at night is the classic Mid-Atlantic pattern.
Sources
SST threshold data is summarized from agency and research sources. Year-to-year ocean conditions vary; verify current SST imagery before each trip.
See live SST for your offshore zone.
Bield: Fish overlays NOAA CoastWatch SST imagery on your chartplotter view, highlights the temperature breaks that match swordfish thresholds, and alerts you when your home zone hits the 64–76°F window.
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