Dengue fever incidence rates of are thought to be contingent upon weather variables, namely precipitation and temperature. Because the activity and survival of the primary vector of dengue fever, Aedes aegypti, is related to local weather conditions, it is believed that there may be a correlation between weather variables and morbidity rates due to dengue fever. The relationship between weather variables and morbidity rates may incorporate a time lag of up to twelve months. In this retrospective study, the statistical association between monthly morbidity rates and monthly temperature and precipiation records in the islands of Trinidad and Tobago were studied, taking monthly time lags of up to twenty-four months into account. It was determined that a statistically significant relationship between temperature and morbidity exists at time lags of six months. In this model there is a positive correlation between morbidity and temperature. Such a model may prove useful in determining possible effects of global warming or in implementing control strategies.