The role of climatic parameters in the prevalence and severity of some common diseases is being
speculated in the face of changing climate of the world. We investigate this supposition by expounding
the relationship between malaria, pneumonia, rainfall and air temperature over Lagos, Nigeria. This
study uses temperature and rainfall data of 60 years and 14 years record of reported cases of malaria
and pneumonia infection. Significant climatic change was detected in both rainfall and air temperature
when standard method of change detection was applied. While rainfall showed a decreasing trend
resulting into drier conditions, temperature tends to increase resulting into warmer environment.
Temperature spells were found to increase in frequency during the last two decades, and there are
tendencies for further increment given the current rate of increasing temperature. Air temperature and
malaria correlation coefficient was high and positive in the months of February and December ranging
between 40 and 95% but high and negative only in November. Coefficient of correlation between rainfall
and pneumonia was high in the range of 50 and 90% and positive in February, May, July and August.
The months of March, April, June, September, October and December also showed positive correlation
but the coefficients are so weak and insufficient (<20%) to justify reasonable relationship between the
variables in these months. We conclude that climatic parameters, rainfall and air temperature, have
profound influence on both malaria and pneumonia occurrence and are responsible directly for
intractable increase of the diseases.