The Mediterranean climate is perhaps one of the most stable in the world. There are truly no severe swings of temperature other than transient unexpected highs or lows. For the most part the weather is annually predictable and in normal range for seasonal shifts. The sunshine duration in Barcelona makes it one of the most attractive vacation areas in the world. Varying from 2500 to 3000 hours of sunshine per year, this southern area tends to have from 1000 to 1500 more hours of sunshine that the rest of Europe. In general, temperatures range from 68 °F (20 °C) during the day to 52 °F at night or 11 °C. Exceedingly large ranges in temperatures are extremely uncommon. Mild winters are the norm for this area of Spain. The coldest months are December, January, and February. High humidity and warm ocean air hold frosting at bay. However, at night frost may be present further inland and in the higher altitude. There has never been a recorded frost in history for the metropolitan areas of Barcelona. A few days a year the temperatures will fall below 50 °F (10 °C) during the coldest part of winter, but average daily temperatures are between 50-63 °F. (10-17 °C). When dressing for a fun outing during this particular season, a bit of layering may be popular. Something light that allows easy transition is recommended.
Summer season in Barcelona typically lasts about six months. May to October and are considered the “summer” season, July and August being the warmest months. A humid 80 °F (27-28 °C) during the day keeps beach-goers happy. Even the 68 °F (20-21 °C) evenings are pleasant and allow for vacationers to enjoy the night life, dining, beaches, and festivals in light cotton clothing. There may be an occasional need for a sweater.
The humidity in Barcelona is comparatively high, with minimal fluctuation. Being at the water’s edge and warm ocean breezes keep the air moist and tolerable. Relative humidity in this part of the country ranges from 72% to 69%, depending on the month of the year.
The annual precipitation rate in Barcelona seems to be fantastically low. With only an average of 55 precipitation days per year, Barcelona feeds much of its water needs off the ocean air humidity and rain falls only 2 to 5 days per month.
Less than 25 inches of rain per year is the average rainfall.
There is rare chance of having a snowball fight in Barcelona, Spain. The frost does fall at night, especially in the high places. January and February are the two months with the highest possibility of snow for Barcelona.
For the most part, Barcelona is an extremely sunny city, with long sunshine durations during the day. However, the sea fog can be eminent in the early spring but burns off quickly when the sun pops out and heats up.
From August until November, cover you head, the storms are coming! Summer storms occasionally yield a high amount of rain, but this is not typical. As much as 7 to 8 inches of rain have been recorded from one dreaded storm.
Light sea breezes blow through from the ocean and make for a cleansing atmosphere. Occasional gale force winds hit the coastline, but staying focused until the storms pass is exceptional practice. It won’t hang around for very long.
Swimming and sun-bathing are quite pleasant in Barcelona with the oceanic temperature near the beach remaining at an average of 68 °F (20-21 °C). In January, the coldest month, sea temperature may drop as low as 55 ° (13 °C).
This can be chilly swimming when coupled with winds coming in from the water.