World Mosquito Day 20 August. Mosquitoes were found for the first time in Iceland last year (2025)- but no new discoveries have been made this year (2026). Nevertheless, Iceland is no longer considered the only mosquito-free country on Earth, along with Antarctica. Experts believe the cause is the warming climate due to climate change.
“Mosquitoes were found here in Iceland in October and November 2025,” says Matthías Alfreðsson, an entomologist at the Icelandic Institute of Natural History. “No specimens have been found this year.”
Thousands of species
There are 3,700 different species of mosquitoes in the world. A specimen of Culiseta annulata was found in a light trap at Mógilsá in the southwest late last year. Shortly afterwards, five specimens were found on red wine ropes (which were used to attract vagrant moths) in the southwest part of the country. Shortly after the 2025 discovery, another species, Culex pipiens, was discovered in a stable in southern-central Iceland, and efforts are underway to eradicate that population, according to Matthías.
World´s biggest killer
The reason a special World Mosquito Day is held on 20 August is that the mosquito is the world’s deadliest animal. Spreading diseases like dengue, West Nile, Zika, chikungunya, malaria, and lymphatic filariasis, the mosquito kills more people than any other creature in the world or between 725,000 and 1 million people each year. Malaria makes up over 80% of all mosquito-caused deaths or about 600,000 yearly.
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The day is intended to raise public awareness, promote prevention and community action with the aim of combating the spread of diseases such as malaria, dengue fever and yellow fever.
Cold and unstable weather
One of the reasons mosquitoes have not thrived in Iceland until now is the cold climate. However, the Arctic region is warming faster than other areas on Earth, creating persistent warm periods in Iceland. However, there is no shortage of mosquitoes in Greenland and Lapland, so there must be more to it than that.
“Some have mentioned the unstable weather, frequent frosts and thaws during the winter, which can disrupt their life cycle,” says Matthías Alfreðsson. “Although that may be the case for certain species, it doesn’t apply to, for example, Culiseta annulata, which survives the winter as an adult. We are also an island in the North Atlantic, which is a significant barrier for many species.”
Matthías points out that while it can certainly be colder in Greenland and Lapland than in Iceland, certain conditions there are more favourable for mosquitoes.
“There, you have species like Ae. nigripes, which is adapted to long winters and short summers, and when the snow starts to melt, good conditions are created, with lots of puddles where the larvae hatch from eggs and develop.”
Conditions are changing
A warming climate and melting glaciers create stable ponds with stagnant water that allow insects to complete their life cycles.
Various species of flies not previously found in Icelandic nature are constantly arriving in the country. They either arrive here on their own or through various forms of international transport. “Although most of them fail to establish a population, conditions can change; higher temperatures, longer summers and milder winters can certainly increase the chances of a species establishing itself.”
