Granada, where it's located

Granada, a city of Andalusia, has a slightly continental climate, with moderately cold winters, and hot summers, dry and sunny. The daily temperature range is often remarkable. The city is in fact located in southern Spain, but at about 700 metres (2,300 feet) above sea level, and a short distance from the mountains of the Sierra Nevada.
Here are the average temperatures at the meteorological station closest to the city.
Granada - Average temperatures
Min (°C)134610141717141053
Max (°C)121417192329343329221613
Min (°F)343739435057636357504137
Max (°F)545763667384939184726155

Precipitation is fairly scarce, since it does not reach 400 millimetres (16 inches) per year, and follows the Mediterranean pattern, so it's more abundant from November to April, while in summer it practically never rains. Here is the average precipitation.
Granada - Average precipitation

Winter, from December to February, is quite cold: the average temperature in January is 7 °C (44.5 °F). The rains, brought by Atlantic depressions, are relatively frequent (it usually rains for 6/7 days per month), but generally not abundant. The days can be mild, especially when the Azores anticyclone settles on the Iberian Peninsula, bringing periods of good weather also in winter, with highs around 15/17 °C (59/63 °F), but typically the nights remain cold, with lows close to freezing (0 °C or 32 °F). Every so often there can be cold waves, with snow and frost. Snow is rare, more rare than in Madrid, but at night it can be very cold. Here are some temperatures recorded in the recent decades at the airport Federico García Lorca: January 1985: -11 °C (12 °F); January 1987: -13 °C (9 °F); January 2005: -11 °C (12 °F), February 2012: -9 °C (16 °F). In the nearby mountain range of Sierra Nevada, home to the highest peaks of the Iberian Peninsula, starting from Mount Mulhacén, 3,482 metres (11,424 feet) high, there are ski lifts.

Summer, from June to August, is hot and sunny; the average temperature in July and August is 25.5 °C (78 °F). The heat is often scorching during the day, given that the maximum temperature can easily reach 35/36 °C (95/97 °F), with peaks of 42 °C (108 °F), although the air is dry. However, at night the temperature remains relatively cool, ranging typically from 15 °C to 20 °C (59 °F to 68 °F), but they can drop to 12/13 °C (54/55 °F) even in midsummer.

Spring and autumn are mild and characterized by a variable weather, so there are periods of good weather, alternating with the passage of Atlantic fronts, which bring clouds and rain. Wind is quite frequent, and the temperature range between night and day is remarkable.

The amount of sunshine in Granada is great in summer, when clear skies prevail: in July there are on average 12 hours of sunshine per day. Sunny days are possible throughout the year: even in December and January there are no less than 5 hours of sunshine per day.
Granada - Sunshine

Granada, Alhambra

When to go

The best times to visit Granada are spring and autumn, especially from mid-April to mid-May, and from mid-September to mid-October, to avoid the summer heat. It's useful to dress in layers, because, given the temperature range, it can get cold at night and hot during the day.

Those who can stand the heat can also choose summer, but must be prepared to stroll around the city in hot weather. However, even in summer, it can be useful to bring a sweatshirt for the evening.