1. This document analyzes temperature data from three cities in Portugal - Beja, Lisbon, and Porto - from 1971 to 2018. 2. The empirical work section describes data collection from the Climate Portal, preparation including transforming the data to make it stationary, and modeling using ARIMA and SARIMA techniques. 3. Results show the average temperature has increased in all three cities over time, with Beja having the highest temperatures. The models produced good ex-post and ex-ante forecasts of the temperature data.