What's the budget for a trip to Spain?

The flight does not count. At €19 to Barcelona and €22 to Madrid, the return costs less than an evening of tapas. It is one of the cheapest connections available from the UK, and there is no point twisting your dates for airfare.

Lodging makes all the difference, and unexpectedly so. A three-star costs €146 in Madrid and €164 in Barcelona, comparable levels. But at the budget end the gap is dramatic: €9 for a hostel in Madrid against €22 in Barcelona. For a budget traveler Madrid is therefore markedly better value, even though the two cities look equivalent on the overall index.

The set lunch is the country's best budget tool. On weekday middays, most neighborhood restaurants serve a full meal, starter, main, dessert and often a drink, for €12 to €15. It is the same meal that would cost double à la carte in the evening.

Sightseeing stays moderate. Madrid's great museums open free-entry windows late in the day, and a large share of the heritage, squares, parks and neighborhoods, costs nothing. In Barcelona, by contrast, the Sagrada Família and the Gaudí sites charge and need booking.

April to June and September-October form the best window, at 14 to 21°C in both major cities. Days are long, terraces open, and rates below their summer peak.

Summer demands a geographic trade-off. Madrid averages over 25°C in July with almost no rain, just 6mm, and the city empties of residents. Barcelona stays more temperate, around 24°C, thanks to the sea. If you travel in summer, the North and the Basque coast offer a far more bearable climate than the interior or Andalusia.

Autumn is wetter than expected in Barcelona, at 92mm in October and 79 in September, against 21 in Madrid. It is the one moment when the two cities' climates diverge sharply.

Winter is mild and cheap, around 5 to 9°C, dry in Madrid. Museums are empty, rates at their lowest, and airfare stays in the same range year-round.

Eating. The menú del día is the institution to know: Monday to Friday middays, a full meal for €12 to €15 at a neighborhood restaurant. Tapas are shared and let two people dine for €25 away from tourist squares. Mind the Spanish rhythm, very shifted: lunch around 2pm, dinner rarely before 9pm, and kitchens closed between services.

Getting around. City centres are walkable. The metro is cheap in both cities, and a ten-ride pack costs far less than single tickets. Between cities, high-speed rail is fast and comfortable, with fares climbing steeply close to departure: booking several weeks ahead often halves the price.

Sightseeing. In Madrid, the Prado, the Reina Sofía and the Thyssen all open free-entry windows, generally late in the day or on Sundays: timing visits to them saves about fifteen euros per museum per person. In Barcelona the logic is reversed, the Gaudí sites charge, often heavily, and book out several days ahead in season.

Currency. The euro, so no exchange fee for a eurozone traveler. Contactless cards work everywhere, including for small amounts.

Language. Castilian, and Catalan in Catalonia, where signage is often bilingual. English works in hotels and tourist areas, less so in neighborhood restaurants.

Rhythm. This is what unsettles visitors most. Lunch is around 2pm, dinner rarely before 9pm, and many kitchens close between 4pm and 8pm. Aiming for the set lunch at midday avoids being left with no option in the afternoon.

Booking. The Sagrada Família and the Gaudí sites run on timed slots and sell out several days ahead in season. Madrid's museums, by contrast, need no booking outside the free windows, which are very busy.