Where is Kalbaisakhi rain in Odisha? Factors influencing Nor’wester, heat wave explored

Odisha is currently facing an extreme heatwave condition, with temperatures breaching 40 degrees Celsius across many districts. What is particularly striking this year is the absence of Kalbaisakhi,  the Nor'wester thunderstorms that traditionally bring relief from oppressive pre-monsoon heat.

As Odisha registers one of its hottest pre-summer seasons in recent memory, meteorologists and climate scientists point to a complex mix of atmospheric, oceanic, and climate-induced factors behind this unsettling anomaly.

Delayed Onset and Suppression of Kalbaisakhi

Kalbaisakhi, or Nor'wester storms, are violent convective systems marked by strong winds, thunder, and heavy rainfall. They typically occur from March through May, offering interim relief before the monsoon's arrival.

In 2025, forecasts had predicted Kalbaisakhi onset by around 20 March. Yet, the storms failed to arrive in their usual vigour.

According to the India Meteorological Department (IMD), Odisha has so far experienced significantly fewer Nor'wester events compared to the historical average of 8-10 such storms during this period.

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Key reasons cited by IMD and other agencies include:

Heatwave Domination: The IMD forecast for March-May 2025 anticipates up to 44 heatwave days in Odisha, the highest since such data began to be systematically collected.

As of early April, the state has already seen more than 18 heatwave days, with temperatures consistently reaching or exceeding 43°C in western and interior districts like Bolangir, Jharsuguda, and Titlagarh.

Atmospheric Conditions: Suppression of convective activities has been linked to multiple meteorological anomalies:

Weak sea breeze intrusions,

Low relative humidity (below 40% in many places during peak hours),

Atmospheric temperature inversions,

Dominance of dry continental air masses.

Such conditions have created an environment that is unfavourable for the vertical cloud development needed to trigger Nor'wester storms.

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Impact of Reduced Kalbaisakhi Activity

The scarcity of Kalbaisakhi activity has direct implications for Odisha's agrarian and water management systems. Traditionally, these pre-monsoon showers recharge groundwater, provide early irrigation for certain crops, and help lower surface temperatures.

This year, paddy cultivators and vegetable farmers in districts like Cuttack, Mayurbhanj, and Ganjam are reporting early signs of moisture stress.

State officials have flagged potential drinking water shortages if the dry spell continues. In Bhubaneswar, average daytime temperatures have hovered around 37 to 41 degrees Celsius since the last week of March — about 4.5 degrees Celsius above normal.

Influence of Prior Monsoon and Climate Patterns

Emerging research links the 2025 Kalbaisakhi failure to broader climatic trends. A significant factor appears to be the deficit in 2024's Indian Summer Monsoon Rainfall (ISMR), which was 11% below the long-period average in Odisha.

According to a Springer Nature study, such deficits can amplify land surface warming and reduce soil moisture, both of which can intensify pre-monsoon heat and reduce the likelihood of storm formation.

Further, long-term data from the Indian Institute of Tropical Meteorology (IITM) shows a steady decline in the frequency and intensity of small-scale pre-monsoon rainfall events across eastern India over the past three decades. This suggests a shift in climatological baselines that may be rendering Kalbaisakhi storms increasingly rare or unpredictable.

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A Worrying Weather Precedent

The case of the missing Kalbaisakhi in 2025 is a textbook example of how local weather anomalies are increasingly intertwined with global climatic changes. As Odisha swelters under record-breaking heat, the absence of these once-regular storms is a grim indicator of the climate change era.