Iran’s national rainfall has risen by 11.3% compared with long-term averages since the start of the current water year, the national meteorological organisation has reported. The figure reflects an overall improvement in precipitation totals, but the picture on the ground remains uneven, with many provinces still facing significant deficits and ongoing drought conditions.
Iran rainfall increase highlights uneven recovery
Meteorological data to 8 Dey show that the country received an average of 72.8 millimetres of rain since the beginning of the water year, compared with a long-term average of 65.4 millimetres. That 11.3% gain contrasts with sharp regional variations: only 12 of Iran’s 31 provinces recorded rainfall above their long-term averages, while 19 provinces stayed below expected levels.
During the seven days leading to 8 Dey, Iran recorded an average of 12.4mm of precipitation, a rise from the long-term weekly figure of 5.6mm — a 121.8% increase that made the week considerably wetter than usual. For the month and season to date, rainfall rose by 95.6% versus long-term measures, with period totals increasing from 6.4mm to 12.5mm.
Regional winners and losers
Hormozgan province stands out as the biggest beneficiary of recent rainfall, receiving 173.7mm from the start of Mehr to 8 Dey against a long-term average of 42.5mm. Other provinces with above-average precipitation include West Azerbaijan, Isfahan, Ilam, Bushehr, South Khorasan, Razavi Khorasan, Sistan and Baluchestan, Fars, Kurdistan, Kerman and Yazd.
By contrast, Tehran remained the most severely affected province, recording an 81.7% drop in rainfall compared with its long-term average. Alborz and Qazvin follow with reductions of 74.9% and 73.9% respectively. Local meteorological authorities say Tehran has largely lain on the margins of recent storm tracks, with systems instead concentrating on southern, northern, north-western and north-eastern regions. The southern slopes of the Alborz range were particularly spared.
Warmer temperatures complicate water recovery
Compounding the uneven rainfall recovery, the country’s mean temperature between 1 Mehr and 8 Dey was around 1.1°C higher than the long-term average. Warmer conditions increase evaporation rates and can reduce the effective contribution of precipitation to reservoirs and groundwater recharge, limiting relief even where precipitation totals have risen.
Experts caution that statistical increases in national rainfall do not automatically translate into recovery of water resources. Storage levels, seasonal distribution of rain, the intensity of events and consecutive dry spells all determine whether ecosystems and water supplies can recover. Regional planners will need to continue monitoring supplies closely and prioritise water management measures where deficits remain most acute.
While the recent uptick in rainfall provides some welcome respite for parts of Iran, the continuation of pronounced regional disparities and higher-than-normal temperatures underlines the challenge of moving from short-term precipitation gains to sustained improvements in water security.
Key Takeaways:
- Iran has recorded an 11.3% increase in average national rainfall since the start of the water year despite uneven distribution across provinces.
- Only 12 provinces exceeded long-term rainfall averages; Hormozgan saw the largest rise while Tehran experienced an 81.7% decline.
- Mean temperatures were about 1.1°C above the long-term average, complicating water recovery despite increased precipitation.
