A monitoring system comprises a module having at least one sensor and preferably skin and ambient temperature sensors within a housing. The device may be durable or disposable. The housing may be provided with certain surface features and shapes to facilitate mounting on and interface with the skin of the wearer for more accurate temperature measurement. A receiver may be provided to obtain and display data from the module. The module may also display the output data. The output data comprises both detected and derived data relating to physiological and contextual parameters of the wearer and may be transmitted directly to a local recipient or remotely over a communications network. The system is capable of deriving and predicting the occurrence of a number of physiological and conditional states and events and reporting the same as output data.