This is the calendar of public holidays for 2019, as published today by the Canarian government.
1 January – Año Nuevo/New Year’s Day
7 January – Epifanía del Señor/Epiphany
2 February – Tenerife’s “island day” for patron saint Virgen de la Candelaria
18 April – Jueves Santo/Maundy Thursday
19 April – Viernes Santo/Good Friday
1 May – Fiesta del Trabajo/Workers’ Day
30 May – Día de Canarias/Canarian Day
15 August – Asunción de la Virgen/Assumption
12 October – Fiesta Nacional de España/Spain Day
1 November – Todos los Santos/All Saints Day
6 December – Día de la Constitución Española/Spanish Constitution Day
25 December – Christmas Day Fiesta del Trabajo
In addition to the above 12 public holidays (11 regional/national plus 1 island day), each municipality has its own two days bringing the total number of holidays in any given area to 14. It is the proliferation of these two local days throughout the island that helps foster the impression that it’s the whole of Tenerife that is constantly on holiday. I will post those below when they’re approved and published.