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Rain that fell across Istanbul during a 48-hour period from 13 October to 15 October exceeded the city's long-term average rainfall total for September and October combined, according to data compiled by the AA correspondent from the General Directorate of Meteorology.

An average of 119.2 kilograms per square meter was recorded across 36 stations over the two days, compared with the 106-kilogram average for the two autumn months, and equal to about 18 percent of the city's annual total.

Two-day total passes seasonal average

Over the 1950-2025 measurement period, the average total rainfall for September in Istanbul was 39.7 kilograms per square meter. For October, that figure was calculated at 66.3 kilograms, giving a combined long-term average of 106 kilograms for the two months.

From 09:00 on 13 October to 09:00 on 14 October, the average rainfall measured at 36 stations was 28.7 kilograms per square meter. From 09:00 on 14 October to 09:00 on 15 October, the average reached 90.5 kilograms.

The city's average annual rainfall is 659.4 kilograms per square meter. The amount that fell during the two days of heavy rain came to 18 percent of that yearly total.

Four districts record more than 200 kilograms

The highest reading during the two days was 274.4 kilograms per square meter at the Beykoz station. Arnavutköy followed with 222.2 kilograms, Sarıyer with 208.3 kilograms and Eyüpsultan with 203.3 kilograms, bringing the number of districts where the 48-hour total topped 200 kilograms to four.

The heaviest rain fell in the city's northern areas. Readings reached 189.8 kilograms per square meter at the Sarıyer ITU Maslak Campus, 185 kilograms in Kilyos, 169 kilograms at the Yavuz Sultan Selim Bridge and 164.4 kilograms in Beykoz Anadolu Feneri.

Beylikdüzü, Silivri and Tuzla saw the least rain

Beylikdüzü, Silivri and Tuzla were the three districts with the lowest rainfall totals in Istanbul. Over the two days, Beylikdüzü recorded 12.9 kilograms per square meter, Silivri 35.3 kilograms and Tuzla 54.6 kilograms.

Key takeaways

• The 13-15 October total averaged 119.2 kilograms per square meter across 36 stations, above the 106-kilogram September-October average.
• Rainfall on the second day averaged 90.5 kilograms per square meter, far more than the 28.7 kilograms recorded on the first.
• Beykoz recorded the highest two-day total at 274.4 kilograms; four districts exceeded 200 kilograms.
• The two days accounted for about 18 percent of Istanbul's average annual rainfall of 659.4 kilograms per square meter.