2025 Annual Review of Myanmar Rainfall

By Dr Kyaw (The Meteorological School)

ACCOMPANIED by a La Niña event towards the end of the year, 2025 is recorded as a year of substantial rain­fall for Myanmar. Based on daily information released by the Department of Meteorology and Hydrology, an analysis of rainfall statis­tics for 2025 reveals that, compared to the decadal average of the past ten years, rainfall was significantly higher across most regions of Myanmar.

According to the measured data, approxi­mately 98.6 per cent of meteorological stations nationwide recorded rainfall exceeding their respective 10-year averages, with an average increase of about 5.11 per cent. The highest percentage increases were observed in some townships in northern Shan State (e.g., Hsipaw, Lashio), the Bago Region, and the Sagaing Region, where rainfall was about 8-10 per cent above the decadal average. In contrast, in typically high-rainfall regions such as the Taninthayi Region and Mon State, the total rainfall for 2025 was only about 2-2.5 per cent above average. Nevertheless, data indicate that rainfall was generally elevated nationwide (Figure 1). The regional average rainfall for 2025 was found to be 5.11 per cent higher than the previous decadal average. The national average rainfall was 2,438.4 millimetres, with a median of 2,400.0 millimetres. Considerable regional variation was observed, ranging from a minimum of 650 millimetres in Myingyan (Mandalay Region) to a maximum of 5,600 millimetres in Dawei (Taninthayi Region).

Despite the overall increase in rainfall for most of the country in 2025, the spatial distribution largely followed Myanmar's in­herent geographical precipitation pattern. The coastal regions of Taninthayi, Mon, and Rakhine, being perennially humid zones, re­ceived rains as usual, with Dawei recording 5,600 millimetres and Gwa (Rakhine) recording 5,400 millimetres. Conversely, the arid central Dry Zone, including stations like Myingyan (Mandalay) and Chauk (Magway), received minimal rainfall of only 650 millimetres. The geographical contrast between these areas resulted in a remarkable precipitation ratio of approximately 8.6:1, highlighting the nature of extreme weather phenomena associated with global climate change. In essence, 2025 was a year that visibly manifested abnormal weather conditions, such as high-intensity rainfall over short periods and a reduced number of rainy days, processes linked to climate change.

A notable finding of this analysis is that some historically dry stations recorded rainfall classified as "above normal" or "much above normal" compared to their local decadal av­erages. For instance, although total rainfall volumes remain low, towns like Pakokku (700 millimetres), Minbu (700 millimetres) in the Magway Region, and Shwebo (950 millimetres) in the Sagaing Region experienced rainfall five per cent to 10 per cent above their ten-year averages. This suggests that the anomalous 2025 monsoon conditions were sufficient to generate increased rainfall even in the central Dry Zone.

Furthermore, records indicate that the 2025 rainfall broke long-standing daily precip­itation records in several areas. New 24-hour rainfall records were set in eleven townships. The most prominent was in Shwegyin (Bago Region), which recorded 311 millimetres on 9 July, exceeding the previous 2024 record (207 millimetres) by 104 millimetres. Additionally, significant increases over previous records were observed in: Katha (Sagaing) with 237 millimetres on 27 June (previous record 199 millimetres in 2001); Taunggyi (southern Shan) with 126 millimetres on 16 May (previous re­cord 88 millimetres in 2002); and Ela (Nay Pyi Taw) with 142 millimetres on 12 July (previous record 89 millimetres in 2018). Notably, Kyaik­khami (Mon) broke its own record from 16 June 2024 (210 millimetres) byw two millimetres, re­cording 212 millimetres on 16 June 2025. These new records indicate an increasing frequency of severe rainstorms or short-duration heavy rainfall events in recent times, underscoring the need for effective management of flood and landslide risks.

The pattern of Myanmar's monsoon rain­fall, driven by the southwest monsoon, exhibits a clear northward decrease in precipitation. Regional rainfall patterns are precisely influ­enced by geographical location and topography. The coastal and southern regions recorded the highest rainfall totals for 2025 (e.g., Taninthayi Region - average ~4,900 millimetres; Mon State - average ~4,600 millimetres; Rakhine State - average ~3,833 millimetres). In con­trast, the arid central regions of Mandalay (average ~1,188 millimetres) and Magway (average ~805 millimetres) received the low­est amounts. Moderate rainfall was observed in the Ayeyawady Region (average ~2,760 millimetres), Yangon Region (average ~2,750 millimetres), and Shan State (average ~1,325 - 1,450 millimetres). This pattern reflects the significant reduction in precipitation with in­creasing latitude and distance inland from the Bay of Bengal. Annual rainfall records suggest that for every degree of latitude northwards, the country's annual rainfall decreases by ap­proximately 238 millimetres. It is important to separately note the rainfall in northern regions (Kachin State, Chin State, upper Sagaing Re­gion), which receive year-round precipitation influenced not only by the monsoon but also by western disturbances. However, the rainfall conditions in these regions for 2025 were within normal parameters (Figure 2).

Geographically, the areas showing the highest percentage increases in rainfall during 2025 were not the typically wet coastal zones but rather the central Dry Zone and the eastern Shan Plateau. For example, towns like Hsipaw (+9.7 per cent) and Lashio (+9.3 per cent) in Shan State experienced markedly higher pre­cipitation. This suggests that the 2025 monsoon circulation system involved atypical elements, such as residual moisture from eastward-mov­ing typhoons and influences from westerlies, which enabled the transport of moisture deeper inland into the highlands and plateau regions.

The implications of this uneven rainfall increase are wide-ranging and present a du­al-edged scenario. For the core Dry Zone ar­eas in Mandalay and Magway Regions, the increased rainfall provides a rare opportunity to recharge soil moisture and groundwater in anticipation of drier years ahead. Conversely, in the high-rainfall zone (which includes 12 stations recording under 4,000 millimetres), it elevated the risks of flooding and landslides.

In summary, 2025 was a year of above-av­erage rainfall across Myanmar, marked by significant new precipitation records from the humid southern coasts to the dry central plains. In the context of increasingly variable annual weather patterns, this review concludes that it is critically important to develop new meteorological research and reassessment frameworks, particularly for long-term plan­ning.