Map from Google - Syria

In Syria the climate is Mediterranean on the coast, with mild and rainy winters and hot and sunny summers, while it becomes arid subtropical in the vast inland areas, with moderately cold winters and torrid and sunny summers. Summer is sunny throughout the country, but the air is humid on the coast, and dry in the rest of the country.
Latakia is located on the coast, and has a Mediterranean climate. The average temperature goes from 12 °C (53.5 °F) in January, to 27 °C (81 °F) in August, which on the coast (but often also in the interior) is, albeit slightly, the warmest month. Here are the average temperatures.
Average temperatures - Latakia
Min (°C)8911141721242522181410
Max (°C)161618222427293029272217
Min (°F)464852576370757772645750
Max (°F)616164727581848684817263

Precipitation amounts to 770 millimetres (30 inches) per year, concentrated from October to April, with a maximum in winter, which is definitely rainy: in December and January, 150/160 mm (5.9/6.3 in) of rain per month fall. Summer, when it never rains, is hot and sunny, but tempered by the breeze. Here is the average precipitation.
Average precipitation - Latakia
Prec. (mm)1501109545255001070100160770

The Mediterranean Sea is warm enough for swimming from June to October, as we can see in the following table.
Sea temperature - Latakia
Sea (°C)181717182124272827252219
Sea (°F)646363647075818281777266

Behind the coast there is a mountain range, a thousand metres (3,300 feet) high, known as An-Nusayriyah, which separates the Mediterranean region from the mainland.

The interior is largely occupied by a plateau, at an altitude between 400 and 1,200 metres (1,300 and 3,900 feet) above sea level, while the altitude of the Euphrates Valley is lower, about 200/300 metres (650/1,000 feet); the temperature decreases with increasing altitude, especially at night and in winter, while summer is usually hot due to the distance from the sea. There are also some mountain ranges, notably the Anti-Lebanon range in the south-west, dominated by Mount Hermon, 2,800 metres (9,185 ft) high.
In the interior of Syria, the climate is fairly homogeneous, however, in winter it's a bit colder in the north, while in summer it gets warmer as we move away from the sea. This means that the most continental areas are those of the north-east, as we can see from the mean temperatures of Qamishli, at 400 metres (1,300 feet) above sea level.
Average temperatures - Qamishli
Min (°C)3461015202423201594
Max (°C)111317222936404035281913
Min (°F)373943505968757368594839
Max (°F)52556372849710410495826655

In Qamishli, 430 mm (17 in) of rain or snow per year fall, as always, concentrated in the cold half-year. Here is average precipitation.
Average precipitation - Qamishli
Prec. (mm)80707060302001204065432

As for rainfall, the wettest areas of the interior are the north-west and the north-east near the border with Turkey, but also a small portion in the southwest (Daraa Governorate), where precipitation goes from 300 to 500 mm (12 to 20 in) per year. For the rest, the climate is desert. However, this distinction, which is shown in the following map, only applies to the winter, because as we have said the summer is dry throughout Syria.

Aridity in the Syrian inland areas

Aleppo, located in the north-west, at 400 metres (1,300 feet) above sea level, has a quite cold winter, with an average in January of 6 °C (43 °F), while summer is hot, with an average in July and August of 28.5 °C (83.5 °F). Here are the average temperatures.
Average temperatures - Aleppo
Min (°C)225914182121171263
Max (°C)101317232934363633271712
Min (°F)363641485764707063544337
Max (°F)505563738493979791816354

Precipitation amounts to 330 mm (13 in) per year, and occurs between October and May, but is moderate only in winter, while it never rains from June to September. During winter, from December to February or early March, cold spells, lasting a few days, with snow and frost, may occur. During some years, the rains from December to March can be abundant. Here is the average precipitation.
Average precipitation - Aleppo
Prec. (mm)60504535202002203560330

The archaeological site of Ebla is situated in the west, at 400 metres (1,300 feet) above sea level and 85 kilometres (50 miles) away from the sea, and has a climate similar to that of Aleppo.
Palmyra, near the modern city of Tadmur, is located in an oasis in the centre of Syria, at 400 metres (1,300 feet) above sea level, and is less rainy, although it has similar temperatures: the daily average is 7.5 °C (45.5 °F) in January and 30 °C (86 °F) in July and August.
Average temperatures - Palmyra
Min (°C)3471216202222191484
Max (°C)121519253135383834282014
Min (°F)373945546168727266574639
Max (°F)54596677889510010093826857

Precipitation amounts to only 130 mm (5.1 in) per year, and is concentrated as usual from October to April, with a maximum in winter. Here is the average precipitation.
Average precipitation - Palmyra
Prec. (mm)202020208000091520135

Palmyra, Syria

The capital Damascus is located in the south-west, 700 metres (2,300 feet) above sea level, and about 80 km (50 mi) from the sea. The climate is not much different from that of Aleppo here as well, with fairly cold winters and torrid summers, the average ranging from 6.5 °C (43.5 °F) in January to 26.5 °C (79.5 °F) in July and August, but the higher altitude makes the summer nights cooler. Here are the average temperatures.
Average temperatures - Damascus
Min (°C)01471114171713941
Max (°C)131519253034373633282014
Min (°F)323439455257636355483934
Max (°F)555966778693999791826857

Precipitation in Damascus amounts to around 160 mm (6.3 in) per annum, however, here too snowfalls and frosts can sometimes occur from December to February. Here is the average precipitation.
Average precipitation - Damascus
Prec. (mm)3030201000000102040160

In spring, and less often in autumn, Syria can be affected by strong southerly winds, which cause sandstorms and raise the temperature considerably.

When to go

The best times to visit Syria are spring and autumn, and in particular the months of April and October.

What to pack

In winter: in Aleppo, Damascus and the plateau: warm clothes, down jacket, hat, raincoat or umbrella, scarf for the wind-borne sand and dust, hiking shoes; on the coast, spring/autumn clothes, sweater and jacket, raincoat or umbrella.

In summer: in Aleppo, Damascus and the plateau: lightweight clothing, of natural fibres, desert turban, hiking boots, sweatshirt or sweater for evenings outdoors, sleeping bag for overnight stays outdoors. For the coast, light clothing, a light sweatshirt for the evening. For women, it is best to avoid low-cut dresses.