KOLKATA, July 11 — For the millions of residents across this sprawling Bengali metropolis, the monsoon season is a familiar rhythm of rain, humidity, and heavy air. But a closer look at the forecast for July 12 reveals a specific, often overlooked factor that shapes daily life here: the wind. According to meteorological data, Kolkata is expected to experience average wind speeds of around 8 km/h on Sunday.
This reading, classified as a “light breeze” on the Beaufort scale — specifically, force 2 — places the city in a narrow band of atmospheric movement. The Beaufort scale, a system developed in 1805 by Sir Francis Beaufort, defines a light breeze as wind speeds between 6 and 11 km/h.
At this level, the scale notes, leaves rustle and wind vanes begin to move. The implications for human comfort are significant. Wind speed plays a critical role in thermal comfort by aiding the process of evaporative cooling.
At 8 km/h, however, that effect is minimal. The wind’s cooling contribution is particularly weak when combined with the region’s characteristic high humidity, which on July 12 is forecast to reach 95 percent.
These light winds are no anomaly. They are consistent with Kolkata’s July averages, where wind speeds typically range from 7 to 12 km/h. The pattern is driven by the monsoon trough’s influence.
For context, a wind speed of 16 to 27 km/h — classified as a moderate breeze on the Beaufort scale — is typically required to provide noticeable relief in such humid conditions. That threshold is nearly double the forecast for Sunday. The gap between what is needed and what is expected underscores a persistent challenge for residents during the monsoon: the air feels heavy, still, and oppressive, even when the rain is not falling.
The Beaufort scale itself has a long history of maritime and meteorological use. Sir Francis Beaufort, an Irish-born Royal Navy officer, originally devised the system to standardise wind observations at sea based on the state of the sails.
Over time, it was adapted for land-based use and remains a reference point for forecasters worldwide. Force 2, the light breeze category, is the third-lowest on the 12-point scale, just above calm and light air. Looking ahead, the forecast for Kolkata suggests that the monsoon trough will continue to dominate the region’s weather patterns in the coming days.
Residents should expect conditions similar to those predicted for July 12: light breezes, high humidity, and the persistent presence of the monsoon’s heavy, wet air. For those seeking relief, the wind offers little assistance.
The combination of low wind speed and near-saturated air means that the body’s natural cooling mechanism will be working against the elements. No specific advisories related to wind speed have been issued for July 12, as the forecast falls within normal seasonal parameters. But for those living through the monsoon, the numbers on the Beaufort scale translate directly into the felt experience of the day.
The leaves will rustle, the vanes will move, but the air will not offer much respite.
