Map from Google - Albania

In Albania the climate is Mediterranean on the coast (with mild, rainy winters and hot, sunny summers), while it becomes slightly more continental in the interior, resulting however really cold only in mountain areas.
In the capital Tirana, which is located about 20 miles from the coast, the climate is similar to that of Rome, Italy, even though the rains are more abundant during the period from October to June. Winter is still mild and rainy, but sometimes at night it can get cold, while summer is hot and sunny, with some very hot days. The average daily temperature in January is 44 °F, while in July and August it is about 76 °F.
Here are the average temperatures of Tirana.
Average temperatures - Tirana
Min (°F)363637455459636357504537
Max (°F)525455647281889081726155

Along the coast, the climate is milder, with less chance of cold nights in winter, and more effective afternoon breezes in summer.
In the cities located in the innermost part of the plain, or those sheltered by the mountains (such as Shkodër), the climate becomes slightly more continental, that is, a little colder in winter, with January averages around 41 °F, and hotter in summer, with highs often around 95 °F.
Moving inland, and with increasing altitude, the climate becomes much harsher, with cold and snowy winters, and progressively cooler summers. For instance, in Korçë, located in the east, 2,950 feet above sea level, the average temperature goes from 33 °F in January, to 70 °F in August.
Average temperatures - Korçë
Min (°F)272734394654575752453932
Max (°F)394148576673818275635445

The rainfall is plentiful along the coast, and even heavier in the hilly and mountainous slopes facing west and south, so that it often exceeds 78 inches per year. Along the coast and in the plain, the rainfall regime is Mediterranean-like, with a maximum amount between autumn and winter, and a minimum in summer, when it seldom rains, while in mountainous areas during summer there can be some thunderstorms in the afternoon.
Here is the average precipitation in Tirana.
Average precipitation - Tirana
Prec. (in)

The only sheltered areas, where it does not rain that much, are the inland valleys, such as that of Korçë, where 32 inches of rain each year fall on average. Here is the average precipitation in Korçë.
Average precipitation - Korçë
Prec. (in)

The temperature of the sea is still a little cool in June, while it becomes acceptable or pleasant from July to September.
Here is the average water temperature in Durrës.
Sea temperature - Durrës
Sea (°F)575757596470737773686459

When to go

The best time to visit the Albanian coast, for swimming and sunbathing, is summer: in July and August the sun always shines and the Adriatic sea is warm.
To visit the cities of the plain as Tirana or Shkodër, it must be remembered that these summer months can be hot, so you can choose the months of May, June and September. October has pleasant temperatures too, but it can be quite rainy.
September, a month in which the sea is slightly warmer than in June, may therefore be an interesting choice, to visit the country and at the same time to have some rest at the beach.

What to pack

In winter: warm clothes, coat, raincoat or umbrella.
In summer: light clothes, a sweatshirt or sweater for the evening or for the mountains.