The cloudy north and the sunny south, explained
It is the question that most baffles new arrivals: it is raining in Puerto de la Cruz while 70 kilometres away, in Los Cristianos, not a drop has fallen. This is not chance or bad luck. It is the trade wind meeting a 3,715-metre mountain, and knowing it changes where you book each excursion.
The mechanism, in three steps
The prevailing wind in the Canaries is the trade wind, blowing from the north-east for most of the year. It arrives loaded with moisture after crossing the Atlantic and runs straight into the bulk of Mount Teide.
Unable to go around it, the air rises. As it rises it cools, and as it cools the water vapour condenses: that is the sea of clouds, the grey layer that clings to the northern slope roughly between 600 and 1,700 metres of altitude.
By the time that same air crosses to the other side it has already dropped its water. It descends dry and warms as it goes down. Southern Tenerife lies in the lee, and that is why it is arid.
What this means for your week
- The north is green because it rains. Anaga, La Orotava, Los Realejos: forest, humidity and frequent fog. This is the Tenerife that never appears in beach brochures.
- The south is dry and sunny almost always. Costa Adeje, Los Cristianos, El Médano.
- And the summit sits above the clouds. This is the part nobody expects: you can leave a hotel under a grey sky, drive up for 45 minutes and find sunshine above a white carpet.
The mistake people keep making
Cancelling the summit trip because it looks cloudy from a hotel in the north. Very often that cloud is below where you are going. The way to know is not to look out of the window: it is to check how high the cloud ceiling is that day.
And the other way round
If you are staying in the south and want to see green Tenerife, expect the day you drive up to Anaga to be closed in with fog. You did not pick the wrong day: in laurel forest the fog is the climate, and it is what keeps the forest alive.
Frequently asked questions
›Can I go up to the summit if it looks cloudy from my hotel?
Often yes, and this is what surprises people most. The sea of clouds sits roughly between 600 and 1,700 metres; Teide reaches 3,715. If the cloud is below your destination, there is sun above it. Check the cloud ceiling height for the day before giving up on the trip.
›Which side of the island should I stay on?
The south for beaches and near-guaranteed sun. The north for forest, hiking and green landscape, accepting more cloud. The island can be crossed by car in a little over an hour, so everything is reachable from either side.
›When does calima happen and how do you notice it?
Calima is air loaded with Saharan dust, arriving from the east or south-east rather than the north-east like the trade wind. It cuts visibility, raises the temperature and turns the sky whitish. It mainly affects high-altitude and stargazing trips, because the air stops being clear.