Kathmandu, May 7
Nepal has recorded average rainfall during this year’s pre-monsoon period, yet the impact has already been significant, with reports of floods and landslides emerging from several districts.
The pre-monsoon period spans March, April, and May, with average rainfall in Nepal typically ranging between 90 to 110 millimeters. As of now, the country has received approximately 107.5 mm of rainfall.
According to meteorologist Sudarshan Humagain of the Department of Hydrology and Meteorology, this amount represents 107.5% of the seasonal average. “This is considered normal rainfall for the pre-monsoon period,” he told Onlinekhabar.
He stated that while rainfall was low in March, April and May have seen significant precipitation, aligning with departmental forecasts.
Rainfall breakdown by month
April saw particularly high rainfall, especially in the second week, aligning with earlier predictions. “Although there was little rain in March, April recorded 126% of the average, amounting to 76.5 mm,” said Humagain.
May has also experienced above-average rainfall so far. “By May 6, the rainfall had reached 18.7 mm, which is about 121% of the average for this period,” he added.
Flooding in various areas
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Rainfall caused by the combined influence of moisture-laden winds from the Bay of Bengal, westerlies, and local weather systems has triggered flooding in multiple locations. In some districts, roads have collapsed, disrupting transportation.
In the under-construction Narayangadh–Butwal road section, particularly in Daunne, rainfall caused major road damage, resulting in hours-long traffic jams.
On April 21, flooding in the Bagmati River along the Kanti Lokpath (Kathmandu–Hetauda route) washed away a culvert pipe, halting travel.
In Udayapur, floodwaters from the Triyuga River on Monday night swept away a culvert connecting Sivae and Belha villages in Chaudandigadhi Municipality-5, carrying away a bus in the process.
What does pre-monsoon rainfall indicate?
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Concerns are growing that road and bridge reconstruction work left unfinished since last year may lead to even greater risk during the monsoon season. Early damage during the pre-monsoon period already hints at heightened vulnerability.
However, meteorologist Humagain noted that Nepal has no dedicated studies correlating pre-monsoon rainfall or drought conditions with the nature of the upcoming monsoon. “We cannot predict the monsoon based on pre-monsoon patterns,” he said.
The Department of Hydrology and Meteorology will release its monsoon forecast in the first week of Jestha (mid-May).
Monsoon forecast: Above-average rainfall and temperature expected
The South Asian Climate Outlook Forum (SASCOF) has projected that Nepal will experience both above-average rainfall and higher temperatures during the monsoon season.
The Department uses SASCOF’s regional forecast as a base for its national outlook. Director-General Kamalraj Joshi said a press conference will be held in the first week of Jestha to announce the national forecast.
Based on the forecast, Nepal’s National Disaster Risk Reduction and Management Authority (NDRRMA) will conduct a risk assessment and release the monsoon preparedness plan.
“The SASCOF projection usually aligns well with Nepal’s experience,” Joshi said, adding that a follow-up briefing will be held after the Sagarmatha Dialogue to explain regional variations in impact.
SASCOF’s map suggests average rainfall in eastern Nepal, slightly above average in central regions, and significantly above average in the far west—marked in blue and dark blue.
The monsoon season typically runs from June to September. In Nepal, it usually begins around June 13 and retreats by October 2, contributing 70–80% of the country’s annual rainfall.
While good rainfall during the monsoon and pre-monsoon benefits agriculture, disaster expert Dr Dharmaraj Upreti warns that it also increases the risks of floods, landslides, and inundation, stressing the need for preparedness and vigilance.
