🇸🇾Syria

Syria (185,180 km²) lies between the Mediterranean Sea (193 km coastline) and the arid interior, encompassing four distinct climate zones: the narrow Mediterranean coastal plain receiving 750–1,200 mm annual rainfall with mild, wet winters and hot, dry summers; the western mountain chains (Jebel Ansariya reaching 1,562 m and Anti-Lebanon Mountains reaching 2,814 m at Mount Hermon) intercepting moisture and creating orographic precipitation; the semiarid interior steppe; and the vast Syrian Desert (Badiyat al-Sham) covering 55% of the country with under 250 mm annual precipitation.

The Euphrates, originating in Turkey, and its tributary the Khabur traverse the northeast providing irrigation despite flows reduced by upstream dams built since the 1970s. Mean annual temperatures rise from the northern highlands to the southeastern desert, where July maxima often exceed 45°C, while coastal areas are moderated by Mediterranean influence. The climate is Köppen BSh (hot semi-arid steppe) in much of the interior and Csa (hot-summer Mediterranean) along the coast, with BWh (hot desert) in the east.

Damascus (elevation 610 m, interior steppe-desert transition) sees January highs of about 13°C with lows near 1°C and July highs of about 38°C with 130 mm annual precipitation concentrated November–March, experiencing summer maxima exceeding 43°C and occasional winter frost. Aleppo (northern steppe, 379 m) registers highs of 11°C and lows of 2°C in January and highs of 37°C in July with 315 mm, historically supporting extensive rainfed wheat cultivation before the severe 2007–2010 drought.

Latakia (Mediterranean coast) records highs of 16°C and lows of 8°C in January and highs of 30°C in July with 700 mm, benefiting from maritime moderation and orographic enhancement. Deir ez-Zor (Euphrates valley, eastern desert, 213 m) experiences highs of 13°C and lows of 3°C in January and highs of 41°C in July with merely 146 mm, entirely dependent on river irrigation. Palmyra (central desert, 400 m) drops to night lows of about 3°C in January and soars to daytime highs of 38°C in July with about 130 mm.

Syria experienced a major drought from 2007–2010, the worst in the instrumental record, within a 1998–2012 eastern Mediterranean drought that tree-ring reconstructions rank as likely the worst in 900 years; climate change made such droughts 2–3 times more likely. This drought caused widespread crop failures and heavy livestock losses, displacing as many as 1.5 million rural residents to urban peripheries and contributing to the 2011 civil war outbreak.

The September 2015 Eastern Mediterranean dust storm blanketed Syria and neighboring countries, causing respiratory emergencies and sharply reduced visibility. The Euphrates River discharge at the Syrian-Turkish border has declined since upstream dams were built from the 1970s, threatening irrigation and drinking water. Summer heatwaves bring extreme temperatures to Damascus and Deir ez-Zor, straining power infrastructure. The Eastern Mediterranean Sea is warming at roughly 0.3–0.6°C per decade, intensifying marine heatwaves.

Our archive covers 13 Syrian cities with daily ERA5 reanalysis data going back to 1940. The hottest July afternoons are in Al Ḩasakah, with average highs around 40.9°C, while Al Qāmishlī has the coldest January nights, with average lows near 1.4°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 2°C.