Clearly, Spring is the best season to visit Madrid. The temperatures are mild, the weather is dry and the citizens of the capital are happier. The terraces are usually full of people, many events are organized and the main festivities of the region take place during this time. And of course, it is a perfect season to have a walk in the parks. For instance, in the Retiro Park: its pond and its Crystal Palace will amaze you.
The Rastro Market, which is the most famous flea market in the capital of Spain, is also interesting in Spring. If you have time, you can also visit the colourful market of flowers installed in Tirso de Molina Square. The festivities of San Isidro, the first bullfights of the season and the decisive matches for Real Madrid and Atletico de Madrid are also a good attraction for tourists.