This study investigates the variability and periodicity of minimum temperature, maximum temperature and sunspot number—a solar activity index in selected synoptic stations across Nigeria from 1946 to 2010. Annual and semiannual effect of solar activity on minimum temperature was observed in all the six stations. This was indicated in the occurrence of modal periodicities of 6 - month and 12-month observed across the six synoptic stations. The synoptic stations are Sokoto (13.01 ̊N, 5.15 ̊E), Ilorin (8.29 ̊N, 4.35 ̊E), Ikeja (6.35 ̊N, 3.20 ̊E), Enugu (6.28 ̊N, 7.33 ̊E), Port-Harcourt (4.51 ̊N, 7.01 ̊E) and Maiduguri (11.51 ̊N, 13.05 ̊E). Similarly, the trends of inter-decadal variability of minimum and maximum temperature show a non -uniformity increase over the analyzed period with a slight decrease before 1960. The long term behavior of minimum and maximum temperature shows a warming rate which ranges from 0.1 ̊C/decade to 0.2 ̊C/ decade across the six stations except for maximum temperature at Ilorin and minimum temperature at Sokoto which is at −0.2 ̊C/decade and 0.3 ̊C/decade respectively.