Home » EUROPE » Canary Islands, Spain: Calima Dust Storm and Heatwave Alert for September 2025, Know About the Health Risks and Travel Precautions

Published on
September 18, 2025

The Canary Islands, one of Spain’s most beloved holiday destinations, are currently grappling with an intense weather phenomenon known as calima, which is causing dust clouds and soaring temperatures. This event, combined with the heatwave, has led to health concerns, particularly for individuals with respiratory conditions. As a result, Spanish authorities have issued a pre-alert for all seven islands: La Palma, El Hierro, La Gomera, Tenerife, Gran Canaria, Lanzarote, and Fuerteventura. The national meteorological agency, AEMET, has declared yellow warnings for the entire archipelago, signalling moderate risks. Tourists and locals alike are being urged to take precautions due to reduced visibility, health risks, and extreme heat.

What Is Calima?

The calima phenomenon refers to the arrival of fine particles of dust from the Sahara Desert, which are carried by strong winds across the Atlantic Ocean. These dust clouds significantly reduce air quality, creating a haze that can make the skies appear murky. While this may seem like a rare occurrence, calima is not unusual in the Canary Islands, particularly during the summer and autumn months. The dust not only diminishes visibility but can also lead to respiratory discomfort, especially in those with pre-existing health conditions like asthma or COPD.

For tourists, understanding the potential risks and knowing how to respond is essential, particularly during this particular calima event, which is accompanied by exceptionally high temperatures.

Current Weather Alerts and Temperature Forecasts

AEMET has issued a series of weather warnings across the Canary Islands, including all seven islands: La Palma, El Hierro, La Gomera, Tenerife, Gran Canaria, Lanzarote, and Fuerteventura. These warnings are in place for both the calima dust phenomenon and extreme heat conditions expected to last throughout the week. As of the latest forecast, the islands are expected to experience temperatures peaking at 36°C in Gran Canaria, with some areas possibly reaching up to 37°C.

In addition to the heat, visibility is expected to be severely reduced to as little as 3,000 metres, particularly in south-facing regions and the peaks of the islands. The calima will also spread to lower-lying areas, including coastal zones, which are typically less affected by the dust. The event is anticipated to last through Wednesday, September 17, with temperature warnings in place until Tuesday evening.

Health Risks Associated with Calima

One of the primary concerns during a calima event is the health risks it poses, particularly to individuals with respiratory conditions. The dust particles carried by the calima are tiny enough to penetrate deep into the lungs, leading to irritation of the airways. Those with pre-existing lung conditions such as asthma, chronic bronchitis, or chronic obstructive pulmonary disease (COPD) may find their symptoms worsened, requiring increased use of medication or even medical attention.

Furthermore, even individuals without chronic respiratory illnesses may experience temporary discomfort such as coughing, sore throat, or eye irritation. Prolonged exposure to the dust can lead to more serious respiratory issues, including difficulty breathing or chest tightness.

AEMET has issued warnings advising people with respiratory or cardiovascular conditions to take extra care. Tourists are advised to stay indoors when possible, particularly during the hottest parts of the day, and to avoid outdoor activities that may exacerbate respiratory discomfort.

Temperature and Heatwave Warnings

In addition to the calima, the Canary Islands are experiencing a heatwave, which is expected to continue through the week. High temperatures, particularly in south- and southwest-facing areas, will make outdoor activities uncomfortable and potentially hazardous. The thermometer is expected to climb as high as 36°C in parts of Gran Canaria, with 37°C not ruled out in some areas. Other islands, such as Lanzarote and Fuerteventura, will experience temperatures close to 34°C.

Heat-related illnesses, such as heat exhaustion or heatstroke, are a significant concern during such high temperatures. Symptoms of heat exhaustion include excessive sweating, weakness, dizziness, nausea, and rapid breathing. If not treated promptly, heat exhaustion can escalate into heatstroke, a life-threatening condition. To avoid such risks, it is crucial to stay hydrated, wear light clothing, and avoid strenuous physical activity during peak heat hours.

Tips for Travelers: How to Stay Safe During Calima and Heatwaves1. Stay Indoors When Possible

During a calima event, the air quality can be poor, and visibility can be significantly reduced. Therefore, it is advisable to stay indoors as much as possible, particularly during the heat of the day. Tourists should avoid unnecessary outdoor activities and stay in air-conditioned spaces to reduce exposure to dust particles and excessive heat.

2. Hydrate and Avoid Dehydration

With high temperatures and low humidity levels, the risk of dehydration is elevated. It’s essential to drink plenty of water throughout the day, even if you do not feel thirsty. Avoid alcohol, caffeine, and sugary drinks, as they can contribute to dehydration. Hydration helps maintain body temperature and ensures that the body can cope with the heat more effectively.

3. Avoid Physical Exertion

Strenuous physical activities should be avoided, particularly during the hottest parts of the day. If exercise is necessary, it is best to do it early in the morning or later in the evening when temperatures are lower. Even moderate activity can lead to overheating and exhaustion during extreme heat.

4. Protect Your Respiratory Health

For those with chronic respiratory conditions, it is crucial to follow medical advice and ensure that medications are readily available. Staying indoors with windows and doors closed can help limit exposure to the dust particles in the air. Wearing a mask, such as an N95 or FFP2, can help filter out harmful particles. Additionally, using air purifiers indoors can reduce the presence of dust and allergens in the air.

5. Monitor Local Weather and Alerts

AEMET provides regular updates on weather conditions in the Canary Islands. Tourists are encouraged to stay informed through local news channels and official weather alerts. It is important to remain aware of any changes in weather patterns and to adjust plans accordingly.

6. Take Extra Caution While Driving

Reduced visibility due to the dust clouds can make driving hazardous. If you are on the roads, it is important to reduce your speed, use headlights, and keep a safe distance from other vehicles. Avoid driving during times of heavy dust or when visibility is significantly reduced.

Conclusion

A heatwave and the calima phenomenon are causing difficult weather conditions in the Canary Islands, and they are predicted to last the entire week. Although this does not lessen the islands’ allure or natural beauty, visitors must take additional safety and health precautions. Travellers can still enjoy the islands while reducing health risks by being informed, staying inside when needed, drinking plenty of water, and taking precautions to protect their respiratory health.