The agency anticipated thunderstorms with moderate rains over most parts of the region later in the day.
Germany is bracing for intense summer heat, with forecasters warning that temperatures could approach 40 degrees Celsius by midweek.
NiMet predicted thunderstorms over parts of Delta, Cross Rivers, Akwa Ibom and Bayelsa later in the day.
The Nigerian Meteorological Agency (NiMet) has predicted rainfall and thunderstorms across the country in its latest weather outlook.
NiMet stated that there were slim chances of light to moderate rains over parts of Plateau and Nasarawa states during the morning hours.
According to NiMet, thunderstorms are expected over parts of Kebbi, Adamawa, Taraba, Sokoto, Kano, Katsina, Zamfara, and Kaduna States later in the day.
Reports said most casualties occurred when lightning struck people working in fields and taking shelter under trees during the rain.
Of the four missing people, one woman was rescued, and a man was found dead. The other two individuals remain missing.
NiMet urged the public to take adequate precautions as strong winds might precede the rains in areas where thunderstorms were likely to occur.
The Nigerian Meteorological Agency (NiMet) has predicted sunshine and cloudiness nationwide from Monday to Wednesday.
