🇸🇻El Salvador

El Salvador (21,041 km²), Central America's smallest and most densely populated nation, extends 270 km east-west between 13°–15°N along the Pacific Ocean, bordered by Guatemala to the west and Honduras to the north and east, with a 307 km Pacific coastline.

The country comprises three parallel physiographic zones: the narrow coastal plain (up to about 30 km wide) with mangrove estuaries and volcanic black-sand beaches; the central plateau (averaging about 600 m) containing the heaviest concentration of population, bisected by the Río Lempa (422 km); and the northern mountain chain reaching 2,730 m at Cerro El Pital near the Honduran border.

El Salvador sits atop the active Central American Volcanic Arc with over 20 Quaternary volcanoes including Ilamatepec (Santa Ana, 2,381 m, last erupted October 2005), San Miguel (Chaparrastique, 2,130 m, frequent activity), and Izalco (historically the Lighthouse of the Pacific).

The climate is predominantly Köppen Aw (tropical savanna) with pronounced wet (May–October) and dry (November–April) seasons controlled by the Intertropical Convergence Zone migration and Pacific moisture. Annual precipitation varies considerably: coastal lowlands receive roughly 1,700 mm concentrated in the May–October wet season, while south-facing highland slopes can receive up to about 2,000 mm through orographic enhancement. The Pacific dry corridor renders El Salvador exceptionally vulnerable to El Niño-driven drought, with the prolonged drought of the late 2010s triggering humanitarian crisis.

San Salvador (capital, Valle de las Hamacas, elevation 658 m) sees highs of about 30–33°C year-round with minimal seasonal variation: nights of about 18°C in January and 21°C in May, receiving 1,723 mm annual rainfall with June–September accounting for about 70% of precipitation but suffering severe dry-season water stress.

The severe Hurricane Mitch (late October to early November 1998) dropped immense rainfall, triggering flash floods and mudslides, killing at least 240 Salvadorans, and causing some $400 million damage.

Hurricane Stan (October 1–5, 2005) coincided with the eruption of Ilamatepec volcano, compounding deadly floods and mudslides that killed about 70 people and forced tens of thousands from their homes. Tropical Depression 12E (October 2011) killed dozens and forced thousands from their homes as more than 400 mm fell in several places.

La Unión (Pacific coast) registers highs of about 35°C in both January and May, with lows of 22°C and 24°C, and 1,742 mm. Santa Ana (western highlands, 665 m) records highs of 31°C and lows of 17°C in January and highs of 33°C and lows of 20°C in May with 1,805 mm.

The Central American Dry Corridor drought, in its fifth straight year by 2019, brought repeated failed harvests for subsistence farmers and widespread food insecurity, and crop failure is among the main drivers of migration from the region. The May–June 2020 convergence of Tropical Storms Amanda and Cristobal killed approximately 30 people, damaged more than 900 homes, and triggered landslides. Climate projections indicate intensifying dry-season drought stress, more extreme precipitation events during the wet season, and continued warming threatening coffee cultivation.

Our archive covers 7 Salvadoran cities with daily ERA5 reanalysis data going back to 1940. The hottest July afternoons are in San Miguel, with average highs around 33.1°C, while Santa Tecla has the coldest January nights, with average lows near 16.4°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.9°C.