Around Raiganj–Islampur, the Kulik and Mahananda floodplains are flood-prone in the monsoon — usually July–September. Summer is dry and hot; winter dawn fog is heavy, and cold air funneling down from the Nepal–Bhutan direction makes it slightly colder than southern Bengal.
Mainly July–September, when heavy rain falls upstream in Nepal–Sikkim. If heavy rain is forecast, riverside residents should stay alert.
Yes, slightly — January can dip to 8–10°C, and the fog is heavy.
Around 39–41°C in May — slightly below southern Bengal, but a chasing loo wind makes the felt heat worse.