2025 recorded both extremes of rain | Number Theory

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As India witnessed rain most prominently in Punjab and Himachal Pradesh during the monsoon, large parts of the world experienced extreme rainfall in 2025. Floods in California in the United States on Christmas eve or those in South and Southeast Asia in late November are only the latest examples of this. Record high precipitation is, however, not the only story of extreme trends in rain in 2025. Countries such as Brazil in South America and Turkey, Hungary, and France in Europe, experienced record low rains. This combination of extremely wet and extremely dry weather has made 2025 one of the most extreme years for rainfall. Here is how.

An area flooded by the Wallace River following heavy rainfall in Washington on December 10. (Reuters)

2025 recorded both extremes of rain

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  On average, total rain is 15th highest this year since 1979, extreme rain the 5th highest

  According to the Global Unified Gauge-Based Analysis of Daily Precipitation data from the Climate Prediction Center (CPC), an agency of the United States government, the global average of rain in 2025 up to December 27 (latest available data) on inhabited land (taken as the land bounded by the 60°N and 60°S latitudes in this analysis), is 791.2 mm. This is the 15th highest for the January 1-December 27 period since 1979, the first year for which CPC has this data. On the other hand, extreme rain in the same period is fifth highest. Extreme rain here is taken as daily rain in a grid – an area bound by latitudes and longitudes 0.50 degrees apart in the CPC data -- higher than the 99th percentile of daily rain for the grid in the 1979-2023 period. In other words, extreme rain is the amount of daily rain that would be ranked in the top 1% for the grid in the 1979-2023 period. The highest total rain was recorded in 1981. The highest extreme rain was recorded in 2024.
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  The average total is not ranked high because some regions also experienced record dryness

  To be sure, while the global average of rain is ranked only 15th highest, 4.3% of the area analysed here recorded its highest ever rain since 1979. This coverage is the sixth highest since 1979. One reason the global average is not ranked this high is that 4.2% of the area also recorded its lowest ever rain since 1979. This coverage for lowest rain is the second highest after 2019, when 4.7% of the area was covered. As the accompanying maps show, the places that received the highest ever rainfall in 2025 are concentrated heavily in Asia, including India, where north-western India, western India, and parts of Karnataka and Telangana in peninsular India recorded high rain. To be sure, parts of other continents also recorded record high rainfall. Record low rainfall, on the other hand, was recorded in countries largely outside Asia, such as Brazil, Canada, France, Turkey, Hungary, Mali, and Democratic Republic of Congo. The combined 8.5% area covered under one of the two extremes – regions that received highest or lowest ever rain since 1979 – is also ranked second highest in 2025. This combined area was the highest in 2006, when 9.8% of the area was covered by the two extremes.
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  Even regions that ended up dry by total rain received extreme rain

  As the previous section shows, almost no area in Brazil received total rain this year that could be ranked in the top 10 since 1979. However, isolated regions in the country did receive extreme rain that could be ranked in the top 10. This is also the case somewhat with the United States, where more places were likely to experience highly ranked extreme rain than highly ranked rain in general. This is in keeping with the trend that as the world warms up, the air is able to hold more moisture. This leads to a lot of rain being dumped in a short time, leading to extreme rain, which may sometimes be followed by long periods of no rain. 2025 was yet another year of this trend continuing.