Field note · Findings

The driest August in eight years.

The rain gauge barely moved this month, and the swell went flat alongside it. Both impressions hold up against the record. They also have almost nothing to do with each other, and September usually undoes them.

31 August 2026 · Rain & swell, this season

If it felt like a dry, small-wave August at Saladita, that was not a trick of memory. The station on the point and the reanalysis record both land in the same place: this was the quietest August in years, on two counts at once.

The two counts are worth separating, because people tend to bundle them into one feeling about "a slow month." The rain and the surf here answer to different oceans.

The rain

Take the rain first, because that is the clearer signal. In the ERA5 reanalysis for this grid cell, August 2026 delivered about 96 mm. A normal August here runs closer to 220 mm. Every August back to 2019 was wetter than this one.

August rainfall by year, ERA5 reanalysis (mm)
YearAugust total
2019169
2020608
2021345
2022223
2023198
2024135
2025224
202696

The weather station on the point tells the same story from a different instrument. Its record only runs a few seasons and its file currently closes on the ninth of the month, but for that opening nine-day window, 2026 logged the least rain of any year it has measured. Wherever you look, the direction agrees.

One caution before anyone declares a drought. A dry August is not a dry year here. June came in wet, near the top of its normal range. And August is, by the calendar, already the front porch of the wettest stretch of the year rather than its peak.

The dry month people are noticing sits right before the wettest one.

The swell

The surf side is real but smaller than the rain story, and it is easy to overstate. Measured as the daily-maximum swell height at Saladita's grid cell, this August averaged about 1.14 m, roughly 3.7 feet of open-coast swell before the point does anything to it. A normal August averages about 1.28 m. So this month ran perhaps a tenth under par, which is a nudge, not a collapse. 2024 was just as flat.

The clearer part is the trend across the summer. The swell has stepped down every month since June, and the drop is not subtle.

Swell height at Saladita, daily-max monthly mean, 2026 (m)
MonthSwellApprox. ft
June1.655.4
July1.334.4
August1.143.7

August ran about a quarter below the June and July average. The first third of the month was the flattest part of all, the smallest opening nine days of any year since 2022. Nothing large came through: the biggest single day peaked near 1.6 m of swell.

Two quiet oceans

Here is why the rain and the swell deserve separate paragraphs. They come from opposite ends of the planet.

The rain is local. It is built from Eastern Pacific convection and tropical moisture parked over this coast, and it switches on and off with systems a few hundred kilometers away. The swell at Saladita is not local at all. This is a Southern Hemisphere point, and its best waves are groundswell that left storms in the Southern Ocean days earlier, thousands of miles south, during the April-to-October window. A flat August means the Southern Ocean has been quiet, which is a completely different fact about the world than a rain gauge reading low.

So the honest version is that two unrelated systems happened to go quiet at the same time. That coincidence is what a "slow month" actually was. It is not one cause with two symptoms.

What September usually does

This is the part worth watching, and it leans against the mood of the month. September is the wettest month of the year on this coast, by a wide margin. Across 2019 to 2025 it averaged about 375 mm, close to 1.4 times a typical August.

More to the point, a dry August has not historically predicted a dry September. 2024 is the cleanest example: a lean 135 mm in August was followed by 706 mm in September, the wettest month in the record. The taps here tend to open in September regardless of how the preceding weeks read.

The swell usually firms up a little too, averaging about 1.45 m in September against 1.28 m in August, as the last strong Southern Hemisphere pulses of the season arrive and Eastern Pacific systems start adding their own south and local energy. September is also the peak of the Eastern Pacific hurricane season, which raises the odds of both heavier rain and larger surf in the same week.

One more piece of context sits underneath all of this. 2026 is an El Niño year, and El Niño leaves a clear fingerprint on late summer at this coast. Sorting the last four decades by phase, El Niño Augusts here average about 170 mm of rain, against 250 mm in neutral years and 358 mm under La Niña. A dry August is close to what an El Niño year tends to deliver, though 2026 has run drier than even the El Niño average. The same phase usually trims September a little too, which is part of why the seasonal model leans below its own normal for the month while climatology still calls September the wettest of the year. There is a full breakdown on the season outlook.

There is a live example of exactly that already on the board. As this note goes up, the National Hurricane Center is giving a tropical wave well offshore a high chance of developing over the coming days. If it spins up, it is the kind of system that would end the dry spell and the flat spell together, which is the ordinary way a quiet Saladita August gives way to a loud September.

None of this is a forecast in the strict sense. It is what the last several years have done in this exact month, which is the best guide the record offers until a real system is close enough to model.

Sources & method

Rainfall. ERA5 daily precipitation for the Saladita grid cell (17.59°N, 101.43°W), 2019–2026, via the Open-Meteo archive, compared month-over-month and year-over-year. Corroborated in direction by the on-site Ambient WS-5000 station daily record, whose file currently ends 9 August. The two instruments disagree on absolute totals, as a point gauge and a reanalysis grid cell will, so they are not cross-quoted; the year-over-year comparison uses ERA5 throughout for consistency.

Swell. Open-Meteo marine model (the same source behind this site's surf forecast), daily-maximum swell wave height at the Saladita grid cell, June–August 2026 and August by year 2022–2026. Open-coast values before refraction at the point; face heights on the wave run larger.

ENSO composite. Each year 1985–2025 classified by its JAS Oceanic Niño Index (NOAA CPC), with ERA5 August and September precipitation composited by phase (8 El Niño, 25 neutral, 8 La Niña years). The rain-by-phase ordering is monotonic and matches the known El Niño suppression of the North American monsoon over southern Mexico. Sample sizes per phase are modest.

Honest caveats. The multi-year windows are short (four to eight Augusts depending on the variable), so a single anomalous year moves the average noticeably. The swell anomaly is modest and within the range of a normal quiet August. The September outlook is climatology and persistence, not a dynamical seasonal forecast; it describes base rates, not a specific prediction for this September. Longer-record context for both signals lives in Rainfall regime structure and Wave power trend.

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