For travelers seeking warmth in Spain during April, the Andalucía region in the south is the most reliable destination. Cities like Seville, Córdoba, and Granada frequently see daytime highs reaching 24°C to 28°C (75°F to 82°F), making it feel like early summer. Another excellent option is the Costa del Sol, where Málaga averages around 22°C with plenty of sunshine. If you are looking for truly "hot" weather suitable for swimming, the Canary Islands (especially Tenerife and Lanzarote) are the best bet, as their subtropical climate maintains temperatures in the mid-20s year-round. While central Spain (Madrid) and the northern coast (Bilbao) can still be quite brisk and rainy in April, the southern Mediterranean coast and the islands offer a pleasant escape. It is an ideal time for sightseeing in the south before the scorching heat of July and August arrives, though the sea temperature in the Mediterranean remains a bit too cool for anything more than a quick dip.