Get the monthly weather forecast for Barcelona, Catalonia, Spain, including daily high/low, historical averages, to help you plan ahead. The climate quite comfortable there the month of may. How warm is the sea around Barcelona in May? How Warm Is Barcelona In May? The average daytime temperatures are around 20°C. The high seasonal norm is 74°F. There are normally 8 hours of bright sunshine each day in Barcelona in May - that's 53% of daylight hours. You can see from the weather log written below, most of the time it will be sunny and warm in May. The average … May is one of the best months of the year in terms of weather in Barcelona. May is an ideal time to visit if you like sunbathing as there in an average of eight hours of sunshine per day. May is in the spring in Barcelona and is typically the 6th warmest month of the year. How about a travel guide, so as not to miss a highlight of the capital of the autonomous community of Catalonia? At this time of year, the maximum temperature can even exceed a hot 25°C one day in ten. the weather in Barcelona in may is rather dry (with 2.4in of precipitation over 8 days). Summary of temperatures and weather in May: Average temperature: 23° C or 73.4 F. Maximum temperature: 27° C or 80.6 F. Minimum temperature: 14° C or 57.2 F. Our Advice. Get the monthly weather forecast for Barcelona, Catalonia, Spain, including daily high/low, historical averages, to help you plan ahead. The climate in Barcelona during May can be summarized as mild and reasonably dry. Daytime maximum temperatures average around 20°C (68°F), whilst at night 12°C (53°F) is normal. Average values and totals based on weather data of recent years: Historical data of recent years in detail: Are you planning a holiday with hopefully nice weather in Barcelona in May 2020? It should be noted an improvement from the previous month since in april it receives an average of 2.6in of rainfall over 9 days. The average minimum temperatures drop down to 12°C. May Sunshine Hours In Barcelona.