Valencia, where it is

In Valencia, a city located on the east coast of Spain, the climate is Mediterranean, with mild, relatively rainy winters and hot, sunny summers. The Valencia Coast includes towns such as Sagunto, Alboraya, Cullera, Gandia, Miramar, Piles and Oliva.
The daily average temperature ranges from 10.5 °C (51 °F) in January to 26 °C (79 °F) in August. Here are the average temperatures recorded at the airport.
Valencia - Average temperatures
Min (°C)5681013182121181496
Max (°C)161719212428313128241916
Min (°F)414346505564707064574843
Max (°F)616366707582888882756661

Rainfall amounts to 470 millimeters (18.5 inches) per year, and follows the Mediterranean pattern, in fact, it is concentrated from September to April. However, the rains are quite rare even in the rainiest months. The rainiest season is autumn because of the prevalence of southerly winds; in winter, it does not rain much, since the weather fronts come from the west, while the city is exposed to the east. In summer, it almost never rains.
Here is the average precipitation.
Valencia - Average precipitation

Winter, from December to February, is a mild season, and it's characterized by sunny periods alternating with periods of bad weather, with wind and rain, which, however, are quite rare. There's a good number of sunny days, with daytime temperatures reaching 17/20 °C (63/68 °F) even in winter. Very cold days are rare: only on colder nights, the temperature drops to freezing (0 °C or 32 °F) or a few degrees below, but even in these cases, it typically remains around 10 °C (50 °F) during the day. In the inland areas of the Valencian Community, it can sometimes snow at an altitude higher than the plain, while snow in the city is a very rare phenomenon: the last major snowfall dates back to January 11, 1960; a less intense snowfall has been recorded on February 12, 1983.

Spring, from March to May, is mild and sunny, with rainy days still possible but not very frequent, and a few afternoon thunderstorms that arrive from the interior in late spring. In May, and sometimes in April, the first hot days occur, with highs around 30 °C (86 °F).

Summer, from June to mid-September, is hot and sunny. Typically, temperatures hover around 28 °C (82 °F) in June and September and around 30/32 °C (86/90 °F) in July and August. The weather is hot and humid, but there is also the breeze from the sea, in short, it's the typical Mediterranean summer. Sometimes, however, there may be heat waves, with highs reaching 35 °C (95 °F). When the wind blows from the interior, temperatures can reach or exceed 40 °C (104 °F), but fortunately, the air in these cases is dry.

Autumn, from mid-September to November, is initially warm, and then becomes gradually milder, while tre first Atlantic low-pressure systems begin to affect the city. Every now and then, the rains can be concentrated in a short time and can be heavy.

Valencia, Plaza del Ayuntamiento

The amount of sunshine in Valencia is very good in summer, when clear skies prevail, it is good in spring and autumn and decent even in winter: there are on average 5 hours of sunshine per day in December, 5 hours and a half in January and 6 hours in February. Here are the average sunshine hours per day.
Valencia - Sunshine

The sea in Valencia is warm enough for swimming from July to September, when it reaches 24/26 °C (75/79 °F) (ie, more than in other parts of Spain); it remains cool until June.
Here are the average sea temperatures.
Valencia - Sea temperature
Temp (°C)141314151721242624211815
Temp (°F)575557596370757975706459

Best Time

The best time for a beach holiday in Valencia is the summer, from June to August. The water temperature is comfortable enough from July to September; however, in September, which is still a good month (especially in the first half), the first Atlantic depressions begin to affect this area. May and June are sunny months, but the sea is still a bit cool, especially in May, when it is actually a bit cold.
Although good weather is not always guaranteed, spring and autumn are ideal for visiting the city and for excursions to the interior, since it can be very hot in summer.