All of the hourly weather data provided with DesignBuilder is supplied by DOE from:
https://energyplus.net/weather
But with the year changed to 2002 as described in Add new hourly weather data.
Most of these "Typical Year" weather files are composite files from multiple years. Each month has been selected to be representative of that month for the period of record. Data is representative of the normal patterns for that month and is not intended to be the average. The selection of months is usually based on a weighting of temperature, humidity, wind, and solar. There are some variations among the weighting, most are similar to the TMY2 done in the US in the 1990s.
You can find details on the EnergyPlus file format in the Climate Analytics help.
Other sources of hourly weather data and associated tools are listed below.
DesignBuilder Climate Analytics - a comprehensive source of hourly weather data with integrated analysis, selection and morphing tools to support building modelling projects. It provides "Design Years", "Actual Years" and "Typical Years" and base data can be morphed to account for future climate scenarios, urban heat islands and various extreme design cases.
Portugal - LNEG, Download a free spreadsheet which can generate hourly weather data for the various Portuguese regions. See: https://www.lneg.pt/servicos/328/2263/.