With climate change, average temperatures are increasing throughout the planet and during the summer an increase in the frequency and intensity of heat waves is being noted. This is where the concepts of tropical night and equatorial night. Each of them has different characteristics and differs in some aspects.
For this reason, we are going to dedicate this article to telling you what tropical night and equatorial night are and their characteristics.
Tropical night and equatorial night
Let's see what a tropical night is.
Although the definition of the term is still being debated, the AEMET Meteorological Glossary points out that the concept refers to a night in which the temperature does not fall below 20 ºC. Another similar term that is being used more and more is “hot night”, which in this case refers to a night with a minimum temperature of 25ºC or higher.
Considering our country, the Canary Islands have the highest number of tropical nights per year, with 92, standing out above the rest of the islands, which is logical due to its latitude. Of these, El Hierro stands out, with an average of 128 tropical nights per year. Southern maritime cities, such as Cádiz, Melilla or Almería, also shine on tropical nights, with 89, 88 and 83 nights a year respectively. In the Balearic Islands they are also common: in Ibiza they sleep most of the year -79 days- with a thermometer above 20 degrees.
In general, Mediterranean cities have quite a few tropical nights each year: more than 50 in the Valencian communities, Murcia and the rest of Andalusia (including the interior), while in Catalonia the average is between 40 and 50. Madrid has 30 tropical nights, followed by Zaragoza, Cáceres, Toledo or Ciudad Real, which usually live between 20 and 30 a year.
Tropical nights will increase by 30% by the end of the century
If you have a little memory, you realize that we are experiencing more and more tropical nights due to global warming related to climate change. Spain is one of the most vulnerable regions in Europe: our biodiversity is in danger, our soils can desertify and problems such as extreme heat waves or droughts can increase.
Autumn 2019 has started to be unusually hot and, according to the forecast of the Spanish National Meteorological Service on climate change, the number of tropical nights will increase by 30% by the end of the century, especially in late spring and early autumn. And from 75 years ago to today, the number of warm nights has quadrupled. The main reason is climate change, related to another human origin: the heat island effect that occurs in large cities, preventing air circulation and having night winds.
For the record, the increases are linear and constant, each of them covering most of the year: in 1950 they occurred between June 30 and September 12 (74 days), while today the interval goes from 6 to 2 September. October to October 6 (127 days). ). According to Aemet experts, the expansion produces more in spring than in autumn. Furthermore, from 1967 to the end of the century, we have only encountered 4 extremely hot months, while we have experienced 7 such events in the last decade.
For a better night's sleep on tropical nights, you can take a hot or cold shower before going to bed, use a cotton cloth, put your feet in cold water first, and put a bottle of cold water in bed for the coolest of the day. When it's time to air out, choose a light, cold dinner instead of a heavy one. Don't forget to stay well hydrated.
equatorial night
Equatorial or hot nights are nights in which the temperature does not drop below 25ºC. Therefore, they are a kind of tropical night, that is, nights with temperatures above 20ºC. However, as not being lower than 25ºC is inherently significant and has a higher associated risk, the specific name of Equatorial Night is used.
Equatorial nights are no strangers to certain climates in Spain. However, they have gained prominence in recent years due to their more regular production. As has been said, tropical nights (and equatorial nights) have increased in Spain in recent decades.
Why does equatorial night occur?
The equatorial night occurs when the temperature does not drop below 25ºC throughout the night. So, as long as the thermometer is at 25ºC or more, we say equatorial night. Nights can be recorded when the thermometer shows at least 25ºC, but temperatures are below that record throughout the day. In that case you have an equatorial night, but not an equatorial minimum.
There is still some debate about these terms, but in principle they are the same in Spain. Like equatorial nights, hot nights are nights in which the temperature does not drop below 25ºC. If the night temperature does not drop below 30ºC, the term "Hellish Nights" is used to refer to this situation. It is not very common in Spain, but in recent years these types of nights are taking place everywhere.
In Spain, these nights can occur more frequently on the coast or inland. They almost always appear in summer and are usually closely associated with very hot events or heat waves. In regions such as Andalusia, Extremadura, Castilla-La Mancha, Madrid, Murcia, Valencian Communities, Catalonia, Aragon and the Balearic Islands, it is not uncommon for one of these nights to appear every summer
They are also found in the Canary Islands, normally in the intrusions of Saharan air and in the central regions, where they can even exceed 30ºC. According to experts, the best temperature to sleep is between 18ºC and 21ºC. Resting is difficult once the mercury starts to rise. This situation is aggravated if the temperature exceeds 25ºC.
So when we sleep at night on the equator, we may be sleeping in very high temperatures (without air conditioning, modern buildings tend to get very hot during the day), perhaps even above 30C. If so, we almost never drop below 25ºC at night and the quality of sleep is poor.
I hope that with this information you can learn more about the tropical night and equatorial night.