Iran is a vast country, and has different types of climate: mild and quite wet on the coast of the Caspian Sea, continental and arid in the plateau, cold in high mountains, desert and hot on the southern coast and in the southeast.
Generally speaking, Iran is an arid country; however, in the west and the north, the rains are a bit more abundant than in the east and the south. The only rainy area is the Caspian Sea coast. Summer is sunny everywhere (except on the shores of the Caspian Sea).

Index


The Caspian Sea



Climate of the Caspian coast

Along the coast overlooking the Caspian Sea, the climate is mild, almost Mediterranean, with fairly mild, rainy winters and hot, humid summers. Daily averages in July and August are around 25 °C/27 °C (77 °C/81 °F), with some chance of thunderstorms. The Caspian Sea is actually a huge salt lake, and the coast is situated about 20 meters below sea level. In the western part, winter is a bit colder than in the eastern part: the January average temperature ranges from 5 (41 °C) in the west to 7 °C (44.5 °F) in the east.

Rasht

Here are the average temperatures of Rasht, a city located a short distance from the western part of the coast.
Rasht - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)2351014182020181384
Max (°C)111113192428303027221714
Min (°F)363741505764686864554639
Max (°F)525255667582868681726357

The annual precipitation amounts to 800/1,200 millimeters (32/47 inches), with a maximum in autumn and a minimum in summer. Here is the average precipitation in Rasht.
Rasht - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)13512011565554540701552151851551360
Prec.(in)5.34.74.52.62.21.81.62.86.18.57.36.153.5
Days131316121176912141313138

In Rasht, the sun rarely shines from October to April, but even in summer, it is not seen so often: on average, it shines just 7 hours a day in June and July. In fact, the summer is not always sunny: some days are cloudy, and as mentioned, some thunderstorms may occur.
Rasht - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours332457755433

The southern Caspian Sea is warm enough for swimming from June to October, as you can see in the following table.
Rasht - Lake temperature
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Temp (°C)131111141924272826231916
Temp (°F)555252576675818279736661

On the slopes at the foot of the Alborz Mountains, the landscape is particularly green, and covered with forests. This is the wettest area of Iran.

Rudkhan Castle

In the area to the east of the Caspian Sea, occupied by plains and hills (Golestan), the climate is arid, almost desert, with hot summers.
Since autumn, though mild, is rainy, if you want to visit this area, the best time is spring, especially the month of May.

The Plateau



Climate of the plateau

Much of Iran is covered by high plateaus and mountain ranges. The plateaus experience high temperature variations between winter and summer, and have a continental climate in the north, with cold winters and hot summers, while the climate is sub-tropical in the central-southern part, where winters are a bit milder, and summers are scorching and sunny. In the northernmost part, winter is very cold because of the influence of cold air masses coming from Russia. In summer, the Iranian plateau heats up a lot, so much so that a thermal low pressure forms, but because of the low humidity, the heat is usually bearable, at least when the temperature is not too high.

Tabriz

In Tabriz, located in the north-west, at 1,350 meters (4,400 feet) above sea level, winter is definitely cold: the average January temperature is -3 °C (27 °F). From November to March, it often snows, and frosts can be intense: the temperature at night can drop to -20 °C (-4 °F). Summer is hot and sunny, though not as hot as in the rest of the plateau: the daily average in July and August is 26.5 °C (79.5 °F), however, there can be scorching days, with peaks of 38/40 °C (100/104 °F). Here are the average temperatures.
Tabriz - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)-7-506111520191482-3
Max (°C)141017232933322820125
Min (°F)192332435259686657463627
Max (°F)343950637384919082685441

Annual precipitation in Tabriz is typical of a semi-arid climate, about 310 mm (12 in) per year. There's a maximum in spring and a minimum in summer, with some rain also in May, and occasional showers in June and September. Here is the average precipitation.
Tabriz - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)252545554020349303025310
Prec.(in)111.82.21.60.80.10.20.41.21.2112.2
Days668107411165660

In Tabriz, the sun regularly shines in summer, while in winter, there is an alternation between cloudy and sunny days.
Tabriz - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours4567911111110764

In Lake Urmia, west of the city, the climate is similar to that of Tabriz.

Tehran

Since the Alborz Mountains partially protect it from the north wind, the capital city, Tehran, has a milder winter compared to other northern cities such as Tabriz. Of course, in winter it can snow and freeze here as well, although less often, and with less intense frosts: the lowest records are around -8/-10 °C (14/18 °F). Tehran is a vast city, close to the mountains, so the northern suburbs, located at an altitude of up to 1,700 meters (5,600 feet) above sea level, are colder than the central and southern areas, which are located around 1,000/1,200 meters (3,300/4,000 feet). So, the average daily temperature in January ranges from 2 °C (35.5 °F) in the northern area to 4 °C (39 °F) in the southern one, while in July, it ranges from 28 °C to 30 °C (82 °C to 86 °F). Summer in Tehran is hot, with scorching days, usually around 35/37 °C (95/99 °F) in July and August, but the humidity is low and the wind blows frequently. Here are the average temperatures.
Tehran - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)-1151116212423191371
Max (°C)71015222834373532241710
Min (°F)303441526170757366554534
Max (°F)455059728293999590756350

In Tehran, only 230 mm (9 in) of rain fall per year, most of which occurring from November to April: the desert is not far from here. Here is the average precipitation.
Tehran - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)35353530153311152035230
Prec.(in)1.41.41.41.20.60.10.1000.60.81.49.1
Days65654110033641

In Tehran too, the sun shines regularly in summer, while in winter, there is an alternation between cloudy and sunny days.
Tehran - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours4567911111110864

In Mashhad, in the north-east of the country, at an altitude of 1,000 meters (3,300 feet), the daily average ranges from 1.5 °C (34.5 °F) in January to 26 °C (79 °F) in July. In winter, snowfalls and severe frosts are possible, and the temperature can drop to around -20 °C (-4 °F), while in summer, the heat is often scorching, with peaks of 40/42 °C (104/108 °F). In a typical year, 250 mm (10 in) of rain fall.
In the south-central and the eastern parts of the plateau, the climate is a bit milder in winter, although the temperature varies with altitude, and frosts are generally possible at night, especially at high altitudes.

Isfahan

In Isfahan, located in the center of the country and at 1,500 meters (5,000 feet) above sea level, the daily average temperature ranges from 3 °C (37.5 °F) in January to 29 °C (84 °F) in July; therefore, the temperatures are similar to those of Tehran. Here are the average temperatures.
Isfahan - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)-2049141922201594-1
Max (°C)91217222834363531241711
Min (°F)283239485766726859483930
Max (°F)485463728293979588756352

Precipitation in Isfahan is very scarce and desert-like: only 110 mm (4.4 in) per year.
Isfahan - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)1515202010110051020112
Prec.(in)0.60.60.80.80.400000.20.40.84.4
Days43442000012424

Sheikh Lotfollah Mosque

At 2,000 meters (6,500 feet) above sea level, the average in January at the latitude of Isfahan is 0 °C (32 °F), while in July it's 25 °C (77 °F): this gives an idea on how much the Iranian plateau heats up in summer.
Qom is located at 900 meters (3,000 feet) above sea level, south of Tehran, at the edge of the Kavir desert. In a typical year, only 135 mm (5.3 in) of rain fall; the average January temperature is 4 °C (39 °F), while summer is particularly hot, so much so that the average in July is 31 °C (88 °F), with highs generally around 40 °C (104 °F).

Shiraz

Shiraz is located in the south, at an altitude of 1,500 meters (5,000 feet); at this latitude, the winter is quite mild even at an altitude so high. The average temperature ranges from 6 °C (43 °F) in January to 29 °C (84 °F) in July.
Shiraz - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)01591317201914941
Max (°C)121519243136383734282114
Min (°F)323441485563686657483934
Max (°F)5459667588971009993827057

Precipitation in Shiraz amounts to 305 mm (12 in) per year, as usual, with a minimum in summer.
Shiraz - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)805050305010052065306
Prec.(in)3.1221.20.200000.20.82.612
Days76641000012633

In addition to the temperature, the southern location of Shiraz is evident also in the fact that the sun shines very often even in winter.
Shiraz - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours788810121111111087

Persepolis is located about 50 kilometers (30 miles) north of Shiraz, at 1,600 meters (5,250 feet) above sea level, and therefore has a climate similar to that of Shiraz.

The Kavir desert (Dasht-e-Kavir, "Great Salt Desert") is a large, arid and inhospitable area, located south-east of Tehran (see the green area in the map). There are sand dunes, but also salt lakes fed by rivers flowing down from the mountains, which are dried for much of the year, partly because of the strong evaporation. The desert is located at an altitude of about 700 meters (2,300 feet). Here, winter is quite cold, while summer is scorchingly hot.

If you want to visit Tehran and the cities of the plateau, the best times are spring and autumn, especially the months of April and October. In the coldest northern cities such as Tabriz, you can move the date by two weeks towards summer (so, mid-April to mid-May and mid-September to mid-October), while in warmer cities like Qom, you can move it by two weeks towards winter (ie mid-March to mid-April and mid-October to mid-November).

The mountains



Mountain zones in Iran

Iran is a particularly mountainous country. This map only gives an indication of the distribution of the main mountain ranges. The major ranges are Alborz, whose highest point is Mount Damavand, 5,610 meters (18,405 feet) high and located south of the Caspian Sea, and Zagros, a long chain located in the west, whose highest peaks are around 4,200 meters (13,800 ft), and which shelter the Iranian plateau from the mild currents of Mediterranean origin. In winter, high mountains experience snowfalls, frosts and strong winds. On the summits, snow cover lasts for many months, but it melts almost everywhere in summer because this season is hot even at high altitudes. Only in the north, on the peaks of Alborz, there are glaciers above 3,500 meters (11,500 ft), for example, on Damavand and Alam Kuh.

The south



Climate of southern Iran

The southern part of Iran, compared with the rest of the country is really a world apart, in fact, it is warm to hot for most of the year, semi-desert and with virtually no winter.
The winter is mild in the west, at the border with Iraq, in the plain of the Shatt-al-Arab, where cities like Dezful, Ahwaz and Abadan are found, and where the average in January is about 11 °C (52 °F), while summer is scorchingly hot, with highs around 43/45 °C in July and August, and peaks of 52 °C (125.5 °F). In winter, cold air masses can sometimes lower the temperature, and there may be some frosts at night. Only the northern part is relatively rainy: in Dezful, 385 mm (15 in) of rain fall per year, with moderate rainfall from December to February, while in Ahvaz, rainfall drops to 230 mm (9 in), and in Abadan, in drops to 150 mm (6 in) per year.

Ahwaz

Here are the average temperatures of Ahwaz, which in summer is one of the hottest cities in the world.
Ahwaz - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)791218232628272319139
Max (°C)182026323945464642362619
Min (°F)454854647379828173665548
Max (°F)64687990102113115115108977966

In Ahvaz, the sun shines for a good number of hours in winter, while in summer, the sky is normally clear.
Ahvaz - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours6778911111110876

Along the coast of the Persian Gulf, winter is even milder, with January averages ranging from 14.5 °C (58 °F) in Busher to 18 °C (64 °F) in Bandar-e-Abbas (the latter is located in the Strait of Hormuz). Here are the average temperatures in Bushehr.
Bushehr - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)101114192426282825211612
Max (°C)192024303436383837332721
Min (°F)505257667579828277706154
Max (°F)66687586939710010099918170

The Persian Gulf is a bit cool for swimming in winter, while it gets very warm in summer, exceeding 30 °C (86 °F) for a few months.
Bushehr - Sea temperature
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Temp (°C)201919222629313232302623
Temp (°F)686666727984889090867973

In summer, the temperatures are high during the day, with highs around 37/38 °C (99/100 °F), and even the night temperatures remain very high, around 28/30 °C (82/86 °F); the humidity coming from the sea makes the heat sweltering and hard to bear. The amount of rainfall is low, typical of a semi-desert climate: 230 mm (9 in) per year in Bushehr and 170 mm (6.7 in) in Bandar-e-Abbas.

Bandar-e-Abbas

Here are the average temperatures of Bandar-e-Abbas.
Bandar-e-Abbas - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)121418212528303028241814
Max (°C)242428323638383837353026
Min (°F)545764707782868682756457
Max (°F)757582909710010010099958679

In Bandar-e-Abbas, the sun often shines all the year round, but there is a certain increase in cloudiness in summer, due to the effects of the summer monsoon, which however, in this area are still poor.
Bandar-e-Abbas - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours78881010999987

In winter, the Strait of Hormuz is a bit warmer than the Persian Gulf, and it's still warm enough for swimming, in fact it does not drop below 23 °C (73 °F) in February and March.
Bandar-e-Abbas - Sea temperature
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Temp (°C)242323262932333332312825
Temp (°F)757373798490919190888277

East of the Strait of Hormuz, on the Gulf of Oman, the climate is practically tropical, since the average temperature of January reaches 20 °C (68 °F). Summer becomes progressively less hot as you move to the east because this area begins to be affected by the Indian monsoon circulation.

Chabahar

In Chabahar (or Chah-Bahar, formerly Bandar Beheshti), the hottest month is June, when average highs are around 35 °C (95 °F), while in July and August, they drop to 32/34 °C (90/93 °F), and there may be overcast and muggy days, though with very little rainfall.
Chabahar - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)151619222528282725231916
Max (°C)252528313435343232323026
Min (°F)596166727782828177736661
Max (°F)777782889395939090908679

In Chabahar, there is a certain decrease in the sunshine hours in summer, which is even more evident than in Bandar-e-Abbas.
Chabahar - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours88991198891098

The Gulf of Oman is warm enough for swimming even in winter, while it becomes very warm in summer, but a little less than in the Strait of Hormuz.
Chabahar - Sea temperature
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Temp (°C)242324262931313029292725
Temp (°F)757375798488888684848177

North of this area, and south-east of the Kavir desert, we find another desert, even more inhospitable, the Lut Desert (Dasht-e-Lut, the area circled in orange in the map). The Lut, generally sandy, is mild in winter during the day, but nights are cold, while it's very hot in summer, especially in the southern part, where the altitude drops to 200 meters (650 feet) above sea level. The peaks of summer heat, around 55 °C (131 °F), make it one of the hottest deserts in the world.
Further south, the region of Sistan and Baluchistan, at least in the part where altitude is below 1,000 meters (3,300 feet), has a similar climate.

Iranshahr

In Iranshahr, at 550 meters (1,800 feet) of altitude, the average ranges from 14.5 °C (58 °F) in January to 37 °C (99 °F) in July, when the average maximum temperature is 45 °C (113 °F): this is one of the hottest cities in the world.
Iranshahr - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)8101419242930282419139
Max (°C)212329354145454441363024
Min (°F)465057667584868275665548
Max (°F)70738495106113113111106978675

In this southern region of Iran, the best months are March and November in the area of the Persian Gulf, while in the eastern part, from the Strait of Hormuz to the east, and also in Sistan and Baluchistan, the best period runs from December to February.

Tropical cyclones



The southeastern part of Iran, overlooking the Gulf of Oman, in the provinces of Hormozgan and Sistan and Baluchestan, may be affected by tropical cyclones. Cyclones typically do not directly affect Iran, but pass to the south, towards the Arabian Peninsula, or to the east, towards Pakistan, bringing nonetheless rain and wind in the southeastern tip of Iran (as happened with Cyclone Phet in early June 2010). More rarely, it can happen that they can reach the coast, and maybe penetrate a bit inland, before dissipating, as happened twice in June 2007, at the beginning of the month with Cyclone Gonu, and at the end of the month with Cyclone Yemyin.
Cyclones form from May to November, and are more frequent at the beginning of the period (May-June), and a little less at the end (October-November).

Best Time



Given the vastness of Iran and its different climates, it is difficult to find a period that is best for all the country, however, you can choose spring, in particular the month of April, which, however, can still be a bit cold in the north and in the mountains, and can already be hot in the south, in the Arabian Gulf and the Gulf of Oman, and even more so in Sistan and Baluchistan. Autumn can be nice as well, especially the month of October, but in the south, it's even hotter than in April, while it may be rainy on the Caspian Sea.

What to pack



In winter: on the coast of the Caspian Sea, bring warm clothes, such as a sweater, a jacket, and a raincoat or umbrella. In Tabriz, the northern plateau and high mountains, very warm clothes, such as a down jacket, a hat, a scarf, and gloves. In Tehran and Isfahan, warm clothes, such as a sweater, a coat, and a hat. In the Lut Desert, spring/autumn clothes (light for the day), a sweater, a jacket, and a scarf for the sand. On the coast of the Persian Gulf and in Bandar-e-Abbas, spring/autumn clothes, a jacket and a sweater; for the Gulf of Oman, spring/autumn clothes (light for the day), a light jacket and a sweater.

In summer: on the coast of the Caspian Sea, bring light clothes, a light sweatshirt for the evening, a scarf for the breeze, and possibly a light raincoat or umbrella. In Tehran and the major cities of the plateau, loose-fitting, light-colored clothing, light and long shirts and pants of natural fibers (cotton, linen), a wide-brimmed hat, sunglasses, comfortable and breathable shoes, a desert turban, and a sweatshirt for the evening. Above 2,000 meters (6,500 feet), you can add a jacket for the evening.
On high mountains, bring warmer clothes depending on the altitude. On the shores of the Persian Gulf and the Gulf of Oman, bring tropics-friendly, lightweight clothes, a desert turban, a sweatshirt and a scarf for air conditioned.
When visiting mosques, you must cover your shoulders and knees, and take off your shoes. Women should avoid low-cut dresses.