Because of the annual summer onslaught of millions of tourists, you'll want to reserve well in advance for stays during the period from early April to late October. Note that high-season rates (May and June for most hotels, rather than July and August) prevail also during the week before Easter, during local fiestas, and for events like the Mobile World Congress in February, the Formula 1 Grand Prix races in May, and for the at-home classico confrontation between FC Barcelona and Real Madrid. When reserving, specify whether you prefer two beds or one double bed. Although single rooms (habitacións sencillas) are usually available, they are often on the small side, and you might prefer to pay a bit extra for single occupancy in a double room (habitación doble uso individual).
Hotel entrances are marked with a plaque bearing the letter H and the number of stars. The letter R (standing for residencia) after the letter H indicates an establishment with no meal service. The designations fonda (F), pensión (P), and hostal (Hs) indicate budget accommodations—although a Spanish hostal (hostel) can often be just as well appointed and comfortable as a hotel.
Hotel ratings used by the Turisme de Barcelona are expressed in stars, with five stars as the highest category. The rating system, however, is essentially based on a checklist of facilities (pool, restaurant, concierge, etc.) more than an evaluation of quality; a hotel can lack one or more of the amenities on the list and still be a better choice than one in the next highest category.
Barcelona's finer hotels are as expensive as those of any other major city—but rates can vary as widely (and mysteriously) as airline tickets. Prices are generally lower from November through March, when hotels have more availability, except when there are huge conventions in town or other special events.