Map from Google - Murcia

Murcia, capital of the Autonomous Community of the same name, is located in the plains, about 35 km (20 mi) away from the coast, in south-eastern Spain, and has a climate that can be defined as almost Mediterranean, but with a particularly remarkable aridity and a very hot summer, and a good sunshine amount even in winter.
The average temperature of January is 10.5 °C (51 °F), that of August is 27.5 °C (81.5 °F). In winter there are several mild periods, while occasionally there can be cold periods, with highs around 10 °C (50 °F) and light frosts at night. In summer, especially in July and August, the temperature can reach 38/40 °C (100/104 °F).
Here are the average temperatures.
Average temperatures - Murcia
Min (°C)5681013182021181496
Max (°C)171821232731343431262017
Min (°F)414346505564687064574843
Max (°F)636470738188939388796863

The rains are scarce, only 300 millimetres (12 inches) per year; in particular winter is drier than it does normally in Mediterranean climates; in summer it almost never rains. Rainy days are particularly rare, although when it rains, sometimes it can rain a lot. Due to the scarcity of rainfall, the landscape is arid.
In the city substantially it never snows, while sometimes it can snow in the higher areas of the province.
Here is the average precipitation.
Average precipitation - Murcia
Prec. (mm)25253025302051030353530300
Prec. (in)

Murcia, Cathedral

In the coast of the province of Murcia, called Costa Cálida, the temperatures are typical of the Mediterranean coast, and therefore summer is less hot than in the capital and in the flat inland areas of the province, although it is more humid (but fortunately sea breezes blow), while in winter very cold temperatures at night are even rarer: typically they reach 0 °C (32 °F) on the coldest nights. The rains, however, remain scarce, around 300 millimetres (12 inches) per year, and there's a good sunshine amount even in winter. Although this is an arid area, the coast of the province of Murcia may on occasion be affected by heavy rains and concentrated in time, which can lead to flooding.
Even along the coast, as in Murcia, in practice it never snows. On the 27th of January 2005, after 60 years, it snowed in Cape Palos, a place more exposed to northern winds than the rest of the coast.
Along the coast we find towns like Cartagena, San Pedro del Pinatar, Santiago de la Ribera, Águilas, Los Alcázares, Mazarrón. There are tourist resort with golf courses, bays and natural harbors, islands and beaches where you can practice surfing; there is also a large lagoon, called Mar Menor, separated from the sea by a strip of sand (called la Manga); inside the lagoon there are five small islands.
In the southern part of the coast we find the natural park of Sierra de la Muela, Cabo Tiñoso y Roldán.

Manga del Mar Menor

Here are the average temperatures of San Javier: the average of January is 11 °C (52 °F), that of August is 25.5 °C (78 °F).
Average temperatures - San Javier
San JavierJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)67810141821221915107
Max (°C)161719202326293028242017
Min (°F)434546505764707266595045
Max (°F)616366687379848682756863

In San Javier, just 310 mm (12.2 in) of rain per year fall; even here you can notice the low number of rainy days.
Here is the average precipitation.
Average precipitation - San Javier
San JavierJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec. (mm)402525252572740404530310
Prec. (in)1.611110.

The sea in the Costa Cálida is warm enough for swimming from July to September, when it reaches 23/25 °C (73/77 °F); it remains cool until June. Here, for example, the temperature of the sea in Cartagena.
Sea temperature - Cartagena
Sea (°C)151415161821232524211816
Sea (°F)595759616470737775706461

When to go

The best time for a beach holiday in the Costa Cálida is the summer, from June to August. For swimming, the best time is from July to September, although from September, which overall is still a good month (especially in the first half), the first Atlantic disturbances begin to occur. May and June are sunny months, but the sea is still a bit cool, especially in May, when it is actually a bit cold.
Even though good weather is not always guaranteed, spring and autumn are ideal for visiting the city of Murcia and making excursions to the other cities of the interior (see Lorca), given that the summer can be very hot.