In most areas of Spain, May means the sun is now officially the rule rather than the exception. This is particularly true in Barcelona, which enjoys delicious averages of 68°F (20°C). You'll also find pleasant weather in the islands and other coastal resort areas. Average high temperatures in Mallorca (72°F22°C), Canary Islands (74°F/23°), Ibiza (72°F/22°C), and Marbella (76°F/24°C) can indeed be high, but often they hover in the high 60s.
For those arriving and spending time in Madrid, highs are a pleasant 72°F/22°C with lows occasionally dipping below 50°F/10°C at night. Spain's northern Atlantic coast and Basque Country is a bit chillier with highs around 66°F/18°F and lows in the low 50s (Fahrenheit). Regardless of where you visit in Spain though, May is a good month to start enjoying some fun in the sun.
Crowds & Costs
May is the last month to take advantage of lower airfares before the summer prices kick into high gear. Discounts on hotels in the more popular destinations like Barcelona and Madrid will be negligible due to the pleasant weather and the proximity of May to summer. For the reasons stated above, visitors will be starting to arrive in places like Barcelona and Madrid, but the crowds won't be so thick as you can count on in June-August.
Where to Go
May is a great month to visit Madrid because it's right before the time when summer heatwaves make a visit to the capital an endurance test rather than a pleasant vacation. Take advantage of the more moderate weather and plan some outdoor activities, be it a walking/cycling/segway tour of the city, visiting the Prado Museum, strolling the famous El Retiro Park, a "secret" foodie tour of local markets/tapas bars, or perhaps a day trip to the rock formations at Cuenca and the Enchanted City.
Also, if you're in Madrid during the middle of the month, be sure to attend the Festival of San Isidro (more on this below), which features a dizzying array of events and parties. Aside from that, you can't go wrong heading for the Mediterranean coast. Everywhere from Barcelona down to Málaga and Cádiz, in the Andalusia region, will be ripe for fun in the sun due to the pleasant weather.
What to Do
May might be the month of most controversy, as mid-May officially kicks off bullfighting season. Whether you view these contests as a cultural touchstone or a relic of barbarism from a bygone age, bullfighting, for the moment, does still exist in this country (although it's been outlawed in Barcelona). Travelers with an interest in Hemingway's Spain can attend weekly bullfighting events in Madrid (at the Plaza de Toros) and Andalusia (in the cities of Málaga and Ronda, among others), and in Valencia (at the Plaza de Toros).
For a different kind of culture, you could opt for a food tour of the country. Like Italy and France, Spain is a nation that puts a premium on cuisine, and its gastronomy has become the stuff of legend. After enjoying the food in Madrid, you could head to the Mediterranean coast and partake of the tapas culture in the Andalusia region as well as in Barcelona. You should also visit the coastal city of Valencia, which is the birthplace of Spain's most famous dish, paella.
Then there's what many view as the Holy Grail of food destinations in Spain: San Sebastian. This historic city on the northern Atlantic coast is famous for pintxos, which are tapas-like small plates and single bites that you can find in various bars and cafés here. Walk into any of these eateries in San Sebastian's historic center and simply point at the morsels that strike your fancy and you'll be living the gastronomic dream in no time.
Events in May
Festival of San Isidro. The 15th of May kicks off this raucous festival celebrating the patron saint of the city of Madrid. Over the course of a week of festivities, local Madrileños don traditional garb and dance the chotis, a 19th-century hybrid ballroom dance popularized in Madrid. Needless to say, there's copious drinking, dancing, and general merrymaking.
Traveling to Spain in March? Check out these great itineraries.
Best of Barcelona & Ibiza - 8 Days. This 8-day itinerary is an ideal Mediterranean holiday that takes advantage of May's pleasant weather. Kick off the trip in Barcelona and then jet off to Ibiza for five days of white-sand beaches, and sparkling seas.
Highlights of Spain's Capital & Andalusia - 10 Days. Start off in the capital city with a walking tour, then make your way south with a stop in Cordoba, followed by the cultural scene of Seville. Madrid is a great destination if you're going to be in Spain during the Festival of San Isidro.