Two people were reported dead in Barabanki district and one in Hardoi.
Met office sources said that the maximum temperatures were below normal by 6 to 11 degree Celsius at one or two places of the state.
Cold wave conditions prevailed over some parts of the state.
Night temperatures rose markedly in Bareilly and Moradabad divisions and changed little elsewhere. They were above normal in Jhansi division, below normal in Gorakhpur, Varanasi, Allahabad, Kanpur, Faizabad, Moradabad, Lucknow, Bareilly and Meerut divisions and normal in the Agra division.
The lowest minimum temperature in the state was 2.5 degree Celsius, recorded at Najibabad (Bijnore).
Weather would be mainly dry and shallow fog would prevail over a few places in the state, the sources said.
Ground frost would occur at isolated places during the next two nights, they added.