Tarifa, where it's located

Tarifa, a town on the southern tip of Spain, has a particular climate, cool and windy, due to the prevailing winds coming from the sea: ponente (west wind) and levante (east wind, more frequent and intense).
Because of waves generated by the wind, this part of the coast of Andalusia is particularly appreciated by surfers and kitesurfers.
You can also go diving around Isla de las Palomas, the southernmost point of Europe, a small island about 200 metres (650 feet) away from the mainland, to which it is connected by a causeway. The pier of Punta de Tarifa is particularly windy. To the south you can see the coast of Morocco, which is just 15 km (9 mi) away. In the strait that separates Europe from Africa (Strait of Gibraltar) you can watch whales and dolphins.

Punta Tarifa, Moroccan coast and Jebel Moussa

There are very large beaches such as Playa de Los Lances and Valdevalquero. Sometimes the wind is so strong that it can lift the sand.
Here are the average temperatures.
Tarifa - Average temperatures
Min (°C)111112131518202019171412
Max (°C)151516171922242523211816
Min (°F)525254555964686866635754
Max (°F)595961636672757773706461

Rainfall amounts to 630 millimetres (25 inches) per year, and follows the Mediterranean pattern, in fact, it is more abundant from October to February, when it's equal to or higher than 75 mm (3 in) per month (and during some years it can be plentiful), while it becomes very rare in summer.
Here is the average precipitation.
Tarifa - Average precipitation

Winter in Tarifa goes from December to February, is mild, and is characterized by sunny periods, alternating with periods of bad weather, with wind and rain. The rains during some years can be heavy or frequent. For its southern location, it is sheltered from the cold: the temperature rarely goes below 5 °C (41 °F) at night, and it rarely remains below 10 °C (50 °F) in the daytime. However, the cold record is -3 °C (27 °F), measured on the 28th of January 2005.

Spring, from March to mid-June, is mild, and gradually becomes less rainy and more sunny. Anyway, especially in March and April, there may still be periods of bad weather. In periods of good weather, the east wind, moderate or strong, cools down the air.

Summer, from mid-June to mid-September, is mild and sunny, with a bit of haze, and definitely not as warm as in southern Spain. Typically, daytime temperatures are not very high, and remain around 25 °C (77 °F); the air is humid and the east wind blows steadily: at certain times it can be moderate, but at others times it can be very strong for weeks. There may be cooler days, with highs about 20/22 °C (68/72 °F), even in July and August. The highest records are around 35/37 °C (95/99 °F), but African heat waves occur rarely: the temperature may not reach 30 °C (86 °F) for an entire summer.

Autumn, from mid-September to November, is mild, and the rains become gradually more frequent. In November, but sometimes also in October, we are well into autumn, with a mild climate, but also cloudy and rainy.

The amount of sunshine in Tarifa is very good in late spring and summer, from May to September, when clear skies prevail (though less than in the rest of Andalusia, because sometimes a bit of mist or some cloud banks can form), while it is acceptable in autumn and winter, when, in addition to sunny periods, cloudy and rainy periods are possible.
Tarifa - Sunshine

Tarifa from above

The sea in Tarifa (we are on the border between the Atlantic Ocean and the Mediterranean Sea) remains cool even in summer, as it reaches a maximum of 22 °C (72 °F).
Tarifa - Sea temperature
Temp (°C)161516161720222222201817
Temp (°F)615961616368727272686463

When to go

The best time for a beach holiday in Tarifa is the summer, from June to mid-September. It is worth while to recall that in periods in which the wind is stronger, sunbathing on the beach may be unpleasant. It's better to bring a sweatshirt and a scarf (and maybe a windbreaker) for chilly and windy evenings.
For hiking and walking, especially if you plan to visit cities of Andalusia such as Seville and Córdoba, you can choose April, May and October, since in that area the summer is very hot.