Spain Weather by Month: 29 Days Over 33°C in Seville's August, 2 in Barcelona's

In August, Seville tops 33°C on an average 28.8 of 31 days — essentially every day. Barcelona, on the Mediterranean, manages 1.9. Their August highs, 37.1°C and 28.9°C, are more than 8 degrees apart. Whether a Spanish summer trip works depends less on when than on where.

The sea and altitude explain it. Barcelona's sea breeze caps the afternoon heat, but humidity in the 70s makes it as sticky as a Seoul summer. Madrid, on a 650 m plateau, reaches 34°C by day with humidity in the 30s, then drops to 20°C at night. Inland Andalusia, home to Seville and Granada, gets the worst of both: hot, and slow to cool. In winter the table turns — Seville's 16°C January is the warmest of Spain's big cities.

Seville's July and August have essentially no rainy days (0.1 in July) — 37°C under a cloudless sky, day after day. Local life bends around it: shops and some sights close or empty out from about 2 to 5 p.m., and dinner starts after 9.

April–May and late September–October put all four cities between 18 and 28°C by day. The variables then are festivals and prices, not weather.

1. Semana Santa (Holy Week) — the processions in Seville and Granada are famous, and room prices soar. Easter 2027 falls on 28 March.
2. Seville's April Fair (Feria de Abril) — two weeks after Easter; Seville's most expensive week for hotels.
3. Barcelona in September — the sea is still warm and the summer crowds have gone, though September–October are Barcelona's wettest months (104 mm in October), mostly in short sharp bursts.
4. Madrid and Granada in October — clear and dry, ideal for shadeless sites like the Alhambra.

Being on a plateau, Madrid has cold winter nights: 11.9 sub-zero nights in an average January. Barcelona and Seville almost never freeze. Winter Spain is far milder than Korea, but poorly insulated buildings mean many visitors find interiors colder than expected; a light down jacket earns its place.

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The most common regret from a Spanish summer trip: "We did Seville in August."

• Period and source: daily values from Open-Meteo's historical weather data (ERA5 reanalysis), 2016–2025, averaged by month at each city-centre coordinate.
• Versus official normals: reanalysis temperatures usually land within 1–2°C of station normals, but downpours get smoothed out, so monthly rain totals come out lower and rainy-day counts slightly higher.
• Rainy day: at least 1 mm of precipitation. Reanalysis picks up even light showers, so counts run high — especially in the tropics, where monthly millimetres are the better guide. Most tropical rain is an hour or two of downpour, not a washed-out day.
• Best months: a first pass from temperature, rainy days and humidity, then adjusted for seasonal factors such as Holy Week, the April Fair and southern heatwaves. It is a judgement call.