hexplace

Month guide · Mértola, Portugal

Mértola in May: weather and what to expect

May is the first month of the year with average highs above 25°C in Mértola. In May, Mértola is the warmest town in Portugal. In May, Mértola averages highs of 26°C and lows of 14°C, with about 7 rainy days and 36 mm of rain. Our rules rate it good for walking and cycling. Crowds in the Alentejo are low.

Based on 1991-2020 climate data · Updated 1 November 2026 · Sources

Average high Town-level26°CLow 14°C
Rainy days Town-level736 mm in total
UV index Modelled8Very high at noon on a clear day
Crowds RegionalLowThe Alentejo as a whole

Is May a good time to visit?

Good for

  • Walking and cycling
    Highs of 26°C with about 7 rainy days

Not ideal for

Nothing stands out as a weaker fit.

Daily highs through May

Town-level · ERA5-Land 1991-2020
Usual range (8 in 10 years)Typical high

Highs climb about 6°C over the month. A day above 35°C happens in roughly 1 May in 4.

May in detail

Town-level · ERA5-Land
MeasureAprilMayJune
Average high22°C26°C31°C
Average low11°C14°C17°C
Rainy days (at least 1 mm)872
Total rainfall48 mm36 mm10 mm
Daylight (mid-month)13 h 08 min14 h 10 min14 h 45 min

Crowds, holidays and daylight

Visitor level RegionalLowNights booked through online platforms in the Alentejo in May 2025: about 30% of the busiest month.

Public holidays in May 2027

  • 1 May Labor Day
  • 27 May Corpus Christi

Local (municipal) holidays are not included.

Daylight mid-month Exact14 h 10 minSunrise to sunset, calculated from the town's coordinates.

Warmer in May

Where is warm in May →

No town in Portugal with precise enough data has a warmer average May high than Mértola.

How May is changing

Town-level · ERA5-Land

May highs are 2.5°C warmer than in 1991-2000, and May rainfall is down about 45% (2016-2025 against 1991-2000). Days above 30°C in May went from 3.9 to 9.3 a year on average.

Questions about Mértola in May

Is May a good time to visit Mértola?

Our rules rate May good for walking and cycling (highs of 26°C with about 7 rainy days).

How warm is Mértola in May?

Average highs are 26°C and lows 14°C. April averages 22°C and June 31°C.

Does it rain much in Mértola in May?

About 7 days have at least 1 mm of rain, with 36 mm in total over the month.

Is Mértola busy in May?

In May 2025, nights booked through online platforms in the Alentejo were about 30% of the busiest month, which we count as low. The figure is for the whole region and leaves out hotels.

How long are the days in Mértola in May?

About 14 h 10 min from sunrise to sunset in the middle of the month.

Sources

Climate: ERA5-Land, Copernicus Climate Change Service (C3S) Climate Data Store, contains modified Copernicus information (CC BY 4.0). Crowds: Eurostat, nights spent in short-stay accommodation booked through online platforms (tour_ce_omn12) (CC BY 4.0). Place names and populations: GeoNames (CC BY 4.0). Climate averages cover 1991-2020. Daylight: calculated from the town's coordinates. Full methodology