Monsoon Set to Arrive Early in Bihar; Thunderstorms, Rain Predicted Across State

Patna: The India Meteorological Department (IMD) has forecast widespread thunderstorms and rainfall across all 38 districts of Bihar on Monday, issuing an orange alert for 18 districts, including Darbhanga, Bhagalpur, and Muzaffarpur, with warnings of lightning strikes in these areas.

A yellow alert has also been issued for 20 other districts such as Gaya and Nawada, where winds are expected to gust at speeds of up to 40 km/h. Light rain is also likely in these regions. Patna is expected to remain cloudy throughout the day with intermittent showers in some parts.

No Major Weather Change Expected Till May 31

According to the IMD’s Patna Centre, the current weather pattern is expected to persist until May 31, with the ongoing spell of pre-monsoon rain and thunderstorms continuing across the state. The recent onset of the southwest monsoon in Kerala on May 24, a week ahead of its usual schedule, has raised hopes for an early monsoon in Bihar, expected to arrive between June 10 and 12.

Weather Over the Last 24 Hours

Over the past 24 hours, light to moderate rain was recorded in Katihar and Supaul districts. Meanwhile, Patna emerged as the hottest location in the state on Sunday with a maximum temperature of 35.4°C, followed by Banka at 31.2°C. The state capital remained overcast for most of the day before skies cleared briefly in the afternoon.

Storms, Rain Likely to Continue

The IMD has warned of continued rain and storm activity until May 31, particularly in northern and eastern Bihar. While this rainfall offers much-needed relief to farmers facing water shortages, authorities have advised caution due to the increased risk of lightning.

Nautapa to Be Milder This Year

The ongoing weather activity is also expected to impact Nautapa, the traditional nine-day period of extreme heat that began on May 25. Meteorologists say the presence of moisture-laden winds from the Arabian Sea and Bay of Bengal has led to increased humidity levels (up to 80%), which may keep temperatures high but diminish the intensity of heat typically associated with Nautapa.

“Due to the persistent storms and high humidity, Nautapa may not be as harsh this year,” an IMD official said.

Above-Normal Rainfall Forecast for Bihar Monsoon 2025

In a positive update for the agricultural sector, the IMD has projected above-normal rainfall for Bihar during the 2025 monsoon season, ruling out the influence of El Nino this year.

In contrast, El Nino conditions in 2023 led to 6% below-average rainfall across the country.

Understanding El Nino and La Nina

El Nino and La Nina are large-scale oceanic phenomena that affect global weather patterns:

• El Nino: Sea surface temperatures rise by 3–4°C, reducing rainfall in typically wet areas while increasing it in drier regions.
• La Nina: Characterized by cooler sea temperatures, often resulting in cloudier skies and increased rainfall in South Asia.