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San Pedro Bay — Monthly Sea-Surface Temperature

Monthly mean sea-surface temperature just offshore of the Ports of Los Angeles and Long Beach, from NOAA's daily 0.25° Optimum Interpolation SST analysis, in degrees Celsius.

ArchiveFrom before CK Economics turned to global trade on October 16, 2026. Its figures are still collected and it stays at this address, but it is no longer part of our trade coverage.

Data status: Current
Official statisticCK forecastSource figures as of October 16, 2026 · Linear trend + seasonal cycle, 5 years, 80% range of backtest errorsSources & methods
Sources
NOAA National Centers for Environmental Information (NCEI)
Period covered
Sep 1981 – Sep 2026
Source figures as of
October 16, 2026
Geography
San Pedro Bay, offshore of the Ports of Los Angeles and Long Beach (0.25° cell at 33.625°N, 118.125°W)
Sector
Climate Economics & Sustainability (archived)
Seasonal adjustment
Not seasonally adjusted
Transformations
Views other than the level (changes, averages, volatility) are calculated by CK Economics from these figures
Forecast method
Linear trend + seasonal cycle
Assumptions
Past patterns continue, with no policy change or shock; fitted to Sep 1981 – Sep 2026
Horizon
5 years
Interval
80% range of backtest errors
Backtest
Errors 40% smaller than repeating the same period a year earlier over the next 3 months, 30% smaller 3–5 years ahead (40 past dates)
Estimated
October 16, 2026
Revisions
Replaced with the source’s latest figures whenever it revises them.
Data status
Current
Limitations
Seasonal swings are left in: compare a period with the same period a year earlier.

Full method · Research standards

Key figures

CK estimate°C · calculated by CK Economics from NOAA NCEI data

Latest · Sep 2026
23.1
+2.1 °C vs a year earlier1
5-year change
+3.7 °C
since Sep 20212
10-year change
+2.4 °C
since Sep 20162
Record high
23.3
Sep 20153
Record low
13
Jan 19893
Where the latest ranks
99th pct.
Higher than 99% of the other 540 observations since Sep 19814
CK forecast · Sep 2031
20.9
80% range 19.6–22.35
  1. 1Latest observation against the observation one year earlier (for weekly data, the nearest within three days).
  2. 2Latest observation against the observation five and ten years earlier.
  3. 3Highest and lowest published observations across the full history shown.
  4. 4Share of the other published observations that are lower than the latest one, rounded down.
  5. 5Final period of the CK forecast, a statistical projection from the model in the methodology, with its 80% range; rounded to three significant figures.

Seasonal pattern

CK estimate

Each month of 2026 and 2025 against the average and range of the same month in 2021–2025. Calculated by CK Economics from the published series.

Monthly °C in 2026 and 2025 compared with the 2021–2025 average and range
2026 2025 2021–2025 average 2021–2025 range

Methodology

Each value is the calendar-month mean of NOAA OISST v2.1 daily sea-surface temperature for one 0.25° grid cell centred at 33.625°N, 118.125°W (covering 33.50–33.75°N, 118.25–118.00°W): open water in San Pedro Bay just outside the Los Angeles–Long Beach breakwater. It is the nearest valid ocean cell to 33.70°N, 118.25°W; the cells immediately to the north are land in the OISST mask. OISST blends satellite (AVHRR) and ship, buoy and Argo observations, so it represents the near-surface temperature of a roughly 25 km box, not a harbor or pier reading. Monthly means are taken from NOAA's Physical Sciences Laboratory, which averages the daily OISST fields to calendar months; the record starts in September 1981 and has no missing months. Values are rounded to 0.01 °C. NCEI first issues each day as Preliminary data and replaces it with Final data about two weeks later. Only months whose every day is Final are shown, so the latest month typically appears around the middle of the following month, and published values are not expected to change afterwards. Verification: monthly means were recomputed from the Final daily files on NOAA's ERDDAP servers (CoastWatch and upwell) for sample months in 1982, 1997, 2010 and the most recent year, and agree with the PSL values to within 0.02 °C. Projection: CK Economics statistical projection. The central path comes from a linear trend estimated from the record (+0.13 °C per decade), the average monthly seasonal cycle and second-order autoregressive errors, which capture multi-month anomalies such as marine heatwaves and El Niño. It runs only as far ahead as backtests support: the model is refitted at past dates, its forecasts are scored against what happened, and it is shown only for horizons where its errors were at least 5% smaller than those of the better of a no-change forecast and repeating the same month a year earlier. The shaded band is the 80% range of those backtest errors. It is a conditional estimate that extrapolates past patterns: it does not model policy, tariffs, recessions or other shocks, and it is not an official forecast of the source agency.

How we collect, check and project every dataset →

Source

NOAA NCEI, Daily Optimum Interpolation Sea Surface Temperature v2.1 (OISST), monthly means as distributed by NOAA PSL (noaa.oisst.v2.highres, sst.mon.mean.nc): https://psl.noaa.gov/data/gridded/data.noaa.oisst.v2.highres.html — figures as published on 16 October 2026.

The 60 projected periods are a CK forecast, not figures from the source; the methodology above describes how they are made.

All data

541 observations, newest first · °C

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PeriodValueChange y/y
Sep 202623.1+2.05 °C
Aug 202623+1.53 °C
Jul 202621.4+1.45 °C
Jun 202619.2+0.2 °C
May 202617.7+0.19 °C
Apr 202618.2+3.18 °C
Mar 202617.1+3.1 °C
Feb 202616.5+2.06 °C
Jan 202616.7+2.17 °C
Dec 202517.6+2.42 °C
Nov 202518.5+2.53 °C
Oct 202519.6+1.3 °C
Sep 202521.1+0.88 °C
Aug 202521.5+0.04 °C
Jul 202519.9−0.63 °C
Jun 202519+0.53 °C
May 202517.6+1.4 °C
Apr 202515.1+0.02 °C
Mar 202514−1.48 °C
Feb 202514.4−0.83 °C
Jan 202514.5−1.27 °C
Dec 202415.1−1.91 °C
Nov 202416−2.15 °C
Oct 202418.3−1.46 °C