San Mateo is a local holiday in 15 municipalities — 414,929 residents in the 2025 register. In 2026 it falls on 21 September; below, where and when it's celebrated.
Verified data
In 2026, the dataset records San Mateo as a local holiday in 15 municipalities, accounting for 414,929 residents in the 2025 register. The most common date is 21 September 2026. 1 municipalities set it on another date.
This comparison uses only the official working calendars incorporated into the dataset for each year.
Demographic profile
Age, citizenship, birthplace and average-age structure from the 2025 Annual Population Census.
53% / 47%
11.8%
63.7%
24.6%
11.2%
16.9%
46.9 years
Comparison with Spain and with the aggregate of the 6 regions where it is observed. All five comparisons are population-weighted and use only the 2025 Annual Census. A positive sign means the covered population has a higher value than the benchmark.
| Demographic profile | Covered population | Compared with Spain | Compared with its 6 regions |
|---|---|---|---|
| Aged 0–14 | 11.8% | -1.1 pp | -0.2 pp |
| Aged 65+ | 24.6% | +3.9 pp | +0.3 pp |
| Foreign citizenship | 11.2% | -2.8 pp | +0.7 pp |
| Born outside Spain | 16.9% | -2.3 pp | +2.7 pp |
| Weighted mean age | 46.9 years | +2.3 years | +0.1 years |
The largest difference from Spain is in “Aged 65+”: +3.9 pp.
Sex comes from the 2025 municipal register; all other metrics come from the 2025 Annual Census. Each percentage uses the total from its own statistical operation. INE municipal tables 68535 and 68541.
When
In 2026 it falls on Monday 21 September in most municipalities. 1 move it to another date (when it lands on a weekend or by local agreement).
| Year | Main date | Municipalities |
|---|---|---|
| 2024 | Saturday, 21 September | 10 |
| 2025 | Monday, 22 September | 5 |
| 2026 | Monday, 21 September | 15 |
Traceability
Official documents linked by the 2026 records. Dates can vary by territory; each municipality page preserves its specific source.
Population: official municipal-register figures at 1 January 2025. INE.
INE municipal tables 68535 and 68541.
Where it's a holiday
Its local holiday in 2026, by region. Each municipality links to its annual record and the available official source.
Together, they account for 414,929 residents in the INE municipal register at 1 January 2025.
Castilla y León2
Castilla-La Mancha2
Principado de Asturias1
FAQ
In 2026, San Mateo is mainly celebrated on 21 September 2026 (Monday). Some municipalities move it to another date on the working calendar.
It's a local holiday in 15 municipalities in 2026, accounting for 414,929 residents in the 2025 register; mostly in Cantabria (5 municipalities).
No. San Mateo is a local-level holiday: it's only a non-working day in the municipalities that set it as their local festival; each keeps its official source.
Other holidays
Per-municipality data with its official source (regional gazette). Every date is verifiable on the municipality page. Data from festivos.io — CC BY 4.0.