KKN Gurugram Desk | According to the India Meteorological Department (IMD), the Southwest Monsoon is expected to arrive early in 2025, with Bihar likely to receive monsoon rains between June 13 and 15. If the forecast holds true, this would mark an earlier onset compared to last year, when the monsoon reached Bihar on June 20, five days behind schedule.
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This year, early monsoon arrival over Kerala—estimated to begin around May 27—is giving rise to expectations that the eastern Indian states, including Bihar, will also see timely or early rainfall.
Key Forecast: IMD Predicts Early Monsoon in Kerala
Traditionally, the Southwest Monsoon arrives in Kerala around June 1, marking the start of the rainy season for the subcontinent. However, IMD’s latest projections indicate an early onset around May 27, setting the stage for a faster-than-usual monsoon progression across India.
IMD officials emphasized that while early onset in Kerala may not always mean early arrival in every region, it often influences favorable monsoon dynamics in adjoining and downstream regions like Bihar, Jharkhand, and West Bengal.
Monsoon Timeline for Bihar (Past 5 Years)
| Year | Bihar Monsoon Onset | Rainfall Deviation |
|---|---|---|
| 2020 | June 13 | Normal rainfall |
| 2021 | June 13 | Below normal |
| 2022 | June 13 | Deficient (-20%) |
| 2023 | June 12 (1 day early) | Deficient (-23%) |
| 2024 | June 20 (5 days late) | Deficient (-20%) |
The normal monsoon onset in Bihar is considered to be June 13, and the average rainfall during the monsoon season is 1272.5 mm. Since 2021, Bihar has not recorded above-average rainfall in any monsoon season, raising concerns for the state’s agriculture-dependent economy.
What IMD Says About 2025
Officials from Patna Meteorological Centre have indicated a high probability of early monsoon arrival this year in Bihar. This is attributed to the predicted early onset over Kerala, supported by oceanic and atmospheric patterns such as sea surface temperatures and lower tropospheric wind circulation.
IMD is scheduled to release a detailed monsoon forecast on May 15, which will include more precise projections for individual regions, including Bihar, Uttar Pradesh, and Jharkhand.
Historical Data: Kerala Monsoon Onset Trends
The following data shows the onset date of monsoon in Kerala over the past few years:
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2024: May 30
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2023: June 8
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2022: May 29
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2021: June 3
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2020: June 1
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2019: June 8
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2018: May 29
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2009: May 23 (Earliest in two decades)
If the 2025 prediction proves accurate, it would be the earliest arrival of monsoon in Kerala since 2009.
Will Early Monsoon Mean Good Rainfall? Not Necessarily
An IMD official clarified that early monsoon onset in Kerala does not guarantee better or earlier rainfall across the country. He said:
“There is no direct correlation between the date of monsoon onset and the total seasonal rainfall. Regional and global atmospheric conditions—such as El Niño/La Niña, Indian Ocean Dipole (IOD), and Madden-Julian Oscillation—play a significant role in rainfall patterns.”
This means Bihar may receive normal, below-normal, or even excessive rainfall depending on how these macro-climate factors evolve during the season.
Monsoon Withdrawal Timeline
Once the monsoon covers the country, it generally starts withdrawing from northwestern India around September 17, and completes its retreat by October 15.
The Southwest Monsoon 2025 is expected to cover the entire country by July 8, following its onset in Kerala by the end of May.
Why This Forecast Matters for Bihar
Bihar is one of India’s most agriculture-dependent states, with a large section of farmers relying solely on rain-fed farming systems. The timing and amount of rainfall directly affect crop cycles, sowing patterns, and yields.
In recent years, monsoon irregularities—both delays and deficits—have severely impacted paddy cultivation, water availability, and livelihoods.
Hence, the possibility of an early and strong monsoon in 2025 has brought a wave of cautious optimism among farmers, agricultural planners, and policymakers.
Government’s Preparedness and Public Advisory
State authorities have indicated that contingency plans are in place for both above-normal and below-normal rainfall scenarios. IMD is also working with agricultural extension departments to issue crop-specific advisories based on rainfall distribution.
People are advised to:
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Stay updated with daily IMD bulletins
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Prepare for pre-monsoon thunderstorms
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Follow government alerts for flood-prone zones and waterlogging areas
Expert View
Dr. Anil Prakash, a senior climate analyst at the Indian Institute of Tropical Meteorology, said:
“A timely monsoon arrival boosts agricultural sentiment and sowing confidence. But the spread and intensity of rainfall over the next three months will be more crucial than the start date.”
He added that global weather models currently suggest a neutral to slightly favorable monsoon phase, with no strong El Niño or La Niña signals.
While an early monsoon onset in Bihar seems likely based on current projections, its impact will depend heavily on intra-seasonal patterns and climate variables. As the state gears up for the 2025 monsoon, all eyes are now on May 15, when the India Meteorological Department will release its official monsoon outlook for the country.
