(ERA5 T2m, 1979–2025)
arrival shift (1949–2025)
within 500 km (1949–2025)
trend (1979–2025)
ERA5 reanalysis (1979–2025) and NHC HURDAT2 storm tracks (1949–2025) at 17.5897°N, 101.4317°W. Linear regression; p-values approximate. Two signals are real: surface warming and an earlier storm season. Two are absent: rainfall total and timing are unchanged.
The coast at Saladita is warming.
ERA5 2m air temperature at the Saladita grid cell, annual means 1979–2025. Linear regression on 47 annual data points.
+0.12°C per decade (p=0.001, R²=0.22). Total implied change: +0.54°C over 47 years.
Real by conventional criteria, moderate in magnitude. Consistent with regional tropical Pacific warming.
Note on data source: NOAA OISST v2.1 satellite-derived SST returns no-data (NaN) at this grid cell due to land masking — the Saladita coast falls inside the coastal exclusion zone of the standard 0.25° SST grid. ERA5 2m air temperature is the next-best continuous long-term record at this exact coordinate. Surface air temperature and SST are highly correlated in the coastal tropics; the direction and approximate magnitude of this trend are consistent with regional SST trends reported in the literature.
The rainy season is not shifting.
ERA5 hourly precipitation at the Saladita grid cell, aggregated into four annual metrics covering the May–October rainy season.
No significant trend in any rainy-season metric over 47 years.
All four metrics fall well short of p<0.05. The p99 daily trend (+6.4 mm/decade, p=0.11, R²=0.056) is the metric most worth watching in future updates. ENSO dominates year-to-year variance; long-term trend signals in this monsoon system are characteristically weak.
Mean seasonal rainfall over the full record: 1,281 mm (May–Oct total). Mean rainy-season onset: around day 145 (approximately May 25). Mean end: around day 307 (approximately November 3).
Storms are arriving earlier, more often, and more intensely.
East Pacific storm tracks within 1,500 km of La Saladita (the "swing zone" covering activity from Mexico's coast to well offshore), with separate tracking of storms within 500 km (direct-impact range). Seventy-seven years, every named East Pacific storm 1949–2025.
First arrival ~19 days earlier now than in 1949. Mean first arrival: day 156 (June 5).
Earlier arrivals compress the gap between rainy-season onset (around May 25) and significant storm risk.
Peak wind within 500 km rising +4.6 kt/decade. Mean peak: 85 kt. 97% of years had at least one storm in the 500 km ring.
The upper end of the intensity distribution trends upward — not every storm, but the worst ones. See the ENSO-conditioned breakdown in the hurricane-phenology analysis.
Storms are spending more time near Saladita.
Two proximity metrics derived from the per-year storm aggregates. The artifact does not record minimum closest-approach distance per storm, so we use storm-days-per-storm as a proxy for track proximity and dwell time.
Storms linger longer in the approach zone. 500 km frequency was already at ceiling (97%).
Mean dwell: 4.2 days per storm, rising at +0.13/decade. The frequency question is settled. Intensity and timing are the active variables.
Pre-1966 storm records carry systematic undercount bias. Before geostationary satellite coverage, storms in open water that did not strike land were frequently missed. Some of the apparent upward trend in storm counts is detection improvement, not real activity increase. The trends survive excluding pre-1966 data, but the exact slope is sensitive to where you draw the cut.
NOAA OISST v2.1 returns NaN at this grid cell. The standard 0.25° SST grid land-masks this near-coast point. ERA5 T2m is used instead. The warming direction is consistent with regional SST records, but the magnitude is a proxy, not a direct ocean measurement.
p-values are approximate. All regression tests assume annual independence. Storm counts, precipitation totals, and temperature in adjacent years are weakly autocorrelated; the true effective sample size is probably 20–40% smaller than the nominal n. The trends that clear p<0.001 are robust to this correction; those near p=0.05 should be treated with more caution.
77 years is a long record but still short for climate. Individual decades with anomalous ENSO sequences — like the persistent La Niña of 2020–2022 — can distort apparent trends. The results here describe the observed 47–77-year period and do not constitute projections.
Rainy-season non-results are also results. The absence of a significant trend in precipitation metrics is informative, not a failure. It means conditions for visitors and residents at Saladita in the May–October window have not demonstrably shifted in total rainfall, timing, or extremes over this record.
Surface warming: real, +0.12°C/decade. Storm season: 19 days earlier, storms more intense. Rainfall: unchanged. Two signals present, two absent.Synthesis · June 2026
Sources
Temperature: ERA5 hourly T2m at 17.5897°N, 101.4317°W via Open-Meteo, 1979–2025 (47 years). NOAA OISST v2.1 returns NaN at this coastal cell; ERA5 T2m substituted. Precipitation: ERA5 hourly precip same cell; rainy season May–Oct; onset = first day cumulative >50 mm; end = last day ≥10 mm. Storms: NHC HURDAT2 East Pacific best-track, 1949–2025 (nhc.noaa.gov); haversine distance; pre-1966 records carry undercount bias. OLS regression via scipy.stats.linregress; p-values approximate (autocorrelation reduces effective n by ~20–40%). Storm results clear Bonferroni threshold (p<0.0125) by wide margins. Scripts: scripts/analyze_climate_trends.py → functions/api/_findings_climate_trends.js.
Analysis run: June 2026