Will there be clouds during the eclipse? This is what the maps say

BarcelonaAugust 12th of this year is a date that has long been marked by everyone on the calendar. The historic total solar eclipse that Catalonia will experience will paralyze the country and, for a few moments, everyone will be looking at the sky. For this reason, the million-dollar question is obvious: will the weather allow us to enjoy this long-awaited event?

Just with the presence of some clouds, the eclipse can be marred. And let's not even talk about rain, which if it fell would be a setback for the millions of people who are nervously and expectantly awaiting this moment. It has been 121 years since a total solar eclipse was seen in our country, and the next one will not be seen again until 2180. Therefore, concern about the weather on that day is more than justified.

It should be taken into account that we will be in the middle of August. A month characterized by heat and sun during the central hours of the day, but also by an increase in afternoon showers and thunderstorms in some areas of the country. And this is the main problem, since the eclipse will take place in the evening, when there may still be remnants of showers or clouds.

This afternoon instability usually occurs in the Pyrenees, the Pre-Pyrenees and the northeastern regions, where the eclipse will be partial. The totality of the phenomenon will be seen in the southern half of the country, where the risk of rain is usually lower at this time of year.

However, summer thunderstorms also occur frequently in the Ports area and the Iberian System. The problem is that the remnants of these clouds often arrive from the west precisely in the evening to the Terres de l'Ebre, Camp de Tarragona and Pla de Lleida, where the eclipse will be total. A factor that will be key to being able to see the phenomenon with more or less guarantees.

Will we be able to see the eclipse?

With the current maps, this Wednesday, August 12, we will be under the effects of an anticyclonic ridge. Therefore, calm will dominate, but with nuances. The areas where there will be concern for the weather forecast until the last moment will be the Pyrenees and Pre-Pyrenees, as new afternoon clouds will grow there, leaving some scattered showers, and at the time of the eclipse these clouds will still be present in the sky in some parts of this sector.

Furthermore, in nearby areas, such as in the counties of Girona or to the north of Central Catalonia and Ponent, the remains of these clouds may also reach and cloud the sky. But in a large part of the coast, the pre-coast, the rest of the interior and also in the area of the totality of the eclipse - Pla de Lleida, Terres de l'Ebre, Camp de Tarragona, a large part of the Valencian Country and the Balearic Islands - the forecasts indicate that the sky will be mostly clear. Only some thin clouds will circulate, which in principle should not cause problems, as well as some harmless cloudiness in the Ports. However, precisely from the evening onwards, some irregular low clouds may form along the sea due to high humidity, which could locally cause trouble in some coastal stretch, especially between the Ebro Delta and the Camp de Tarragona.

There will also be some low clouds in Alicante and in the south of the counties of Valencia. Therefore, there will be exceptions, but in most of the territory the eclipse will be visible. In addition, there will be a bit of African dust in suspension that may slightly cloud the sky, but in principle it should not be a problem or an impediment to seeing the Sun well, it may simply increase its yellowish and reddish color.

The North African warm air bubble will strengthen, making the atmosphere suffocating and with some suspended dust that may cloud the sky. At the time of the phenomenon, most regions will still be above 30 ºC, with a lot of sultriness near the sea. Therefore, wherever we go, we should bring water to stay hydrated while observing the eclipse, as well as sunscreen, light clothing, and caps.

What do the data from recent years say?

If we take a look at the open historical data from Meteocat, since 2009 there has only been one August 12th that has been particularly rainy in general in Catalonia: that of 2010. It is the exception, since the rest of the years indicate that on August 12th it rains less than usual in our region at this time of year. Few years has it rained on a day like this much more than usual and in general. This would translate into the fact that if there are afternoon storms, they could be more residual and concentrated in mountain areas. In this graph you can see the rain collected in liters per square meter in the set of Meteocat stations distributed throughout the country every August 12th since 2009 and the anomaly with respect to the average for the period.

Regarding cloud cover, according to data analyzed and provided by Aemet specifically for this eclipse, in a large part of Catalonia and the Valencian Community – also in a large part of the territory where the totality band of the eclipse will be – there is between a 30% and 50% chance that on August 12th the sky will be clear or partly cloudy; a probability that rises to 65% in the Ebro Delta, on the coast of Barcelona and Valencia, in a large part of the Alicante regions, and in most of the Balearic Islands, thus becoming the areas with the highest likelihood of not suffering from clouds. On the other hand, in the Alt Pirineu – where the eclipse will be partial – the probability that clouds will cause trouble is very high.

Where are the best views?

Regarding the areas where this phenomenon can be seen, we must imagine a straight line approximately between Vilanova i la Geltrú and Lleida: the municipalities and regions located south of this line will see the Sun completely hidden by the Moon, while those to the north will witness a slightly partial eclipse. In this interactive map, you can discover how this spectacular phenomenon will look from your municipality and what will be the best areas to enjoy it to the fullest.