When was the first successful weather forecast based on telegraph data issued?

A major step toward modern forecasting came on 1 August 1861, when the British meteorologist James Glaisher began issuing forecasts using weather reports sent by telegraph from around the country. This allowed meteorologists to compare conditions over a wider area and predict changes more systematically than with local observations alone. It was part of the early development of organized weather services in the 19th century. Telegraph networks later became essential to national weather bureaux and routine forecasting.