1. A method of predicting future connectivity of a portable electronic device comprising: accessing a query composite signature vector providing an indication of a plurality of radio scenes detected at the portable electronic device at a plurality of respective predetermined reference times, each radio scene identifying transmitters and associated signal strength of signals received by the portable electronic device at a respective predetermined reference time of the plurality of respective predetermined reference times; retrieving one or more connectivity predictions from a corpus of pairs of: a composite signature vector, providing an indication of a plurality of radio scenes detected at one or more different portable electronic device at the plurality of respective predetermined reference times, and associated connectivity information, each of the one or more connectivity predictions retrieved based on a similarity between the composite signature vector and the query composite signature vector, wherein each of the one or more retrieved connectivity predictions comprises a composite signature vector and associated connectivity information from the corpus of pairs; and providing a prediction of future connectivity of the portable electronic device based on the one or more retrieved connectivity predictions.