Resolution criteria

This market resolves to YES if the India Meteorological Department (IMD) or the Meteorological Centre Patna (IMD Patna) officially declares that the southwest monsoon has advanced into or reached any part of Bihar on or before June 30, 2026 (11:59 PM IST).

The market resolves to NO if the southwest monsoon does not officially enter Bihar by this deadline, or if the official declaration of its arrival in the state occurs on or after July 1, 2026.

Primary sources of truth for resolving this market include:

• Official IMD National Press Releases (available via IMD Monsoon Information)

• IMD Patna's Regional Portal and their official X/Twitter feed (@imd_patna)

• Reputable national and regional news publications reporting on IMD's official onset declarations for Bihar.

Pre-monsoon rainfall, isolated thunder showers, or local storm activity in June do not constitute the official arrival of the monsoon unless explicitly declared as the southwest monsoon onset/advance into the state by the IMD.

Background

The southwest monsoon typically reaches Bihar between June 15 and June 18, usually entering through the northeastern districts of Purnea and Kishanganj.

For the 2026 monsoon season, the IMD announced the arrival of the monsoon in Kerala on June 4, three days behind its normal onset date of June 1. Following its arrival, the system has advanced rapidly northward through southern and central India. However, the IMD has issued a below-normal overall rainfall forecast for India in 2026 (90% of the long-period average), alongside predictions of above-normal heatwave days and potential delays affecting eastern states like Bihar.