Tenerife has many micro-climates. Even within a 10km distance, the temperatures can vary considerably, from 20-35 degrees on the coast to 15-20 degrees in the city/nature, and as low as 0-10 degrees in the National park (at over 2000m altitude).

You might need summer clothes and swimming suits (if you want to enjoy and go to the beach!), but also warmer clothes, jackets, and comfortable shoes (if you want to visit the mountains and forests at different altitudes).

 

You can check the official weather on http://www.aemet.es/en

For the course activities, you can choose semi-formal clothing and comfortable shoes.