Map from Google - Iraq

In Iraq the climate is desert in the south-central part, with mild winters and hot, long summers, it's semi-desert in the north, with relatively cold winters, while in the northern mountains, the climate is cold and rainy (or snowy) in winter, warm and sunny in summer, but with cooler nights due to the high altitude.

Climates in Irak

-The north-eastern part of Iraq (zone 1 on the map), occupied by the mountains of Iraqi Kurdistan (Zagros and Taurus), has cold and rainy winters, while summers are hot and dry, even torrid up to quite high altitudes. The annual precipitation varies between 27 and 40 inches, and occurs between October and April. As a matter of fact, this is the only area of Iraq which receives substantial rainfall. In Sulaymaniyah, 2,800 feet above sea level, the average temperature in January is 39 °F, while in July and August it's 88 °F. So the summer is hot as well as sunny, but the winter is cold, with possible snow and frost, when cold air masses arrive from the north.
Here are the average temperatures of Sulaymaniyah.
Average temperatures - Sulaymaniyah
SulaymaniyahJanFebMarAprMayJunJulAugSepOctNovDec
SulaymaniyahJFMAMJJASOND
Min (°F)323441505968757568574636
Max (°F)46506170829510210295826652

The annual precipitation amounts to 29.3 inches, most of which occurring from November to April, while it never rains from June to September. Here is the average precipitation.
Average precipitation - Sulaymaniyah
SulaymaniyahJanFebMarAprMayJunJulAugSepOctNovDecYear
SulaymaniyahJFMAMJJASONDY
Prec. (in)5.15.75.13.91.600000.634.329.3
Days

In the northernmost mountainous area, in inland valleys, winter becomes freezing cold, and at higher altitudes heavy snowfalls occur. The highest peak of Iraq is Cheekha Dar, 11,850 feet high, on the border with Iran.
-North-west of Mesopotamia, in the hilly area towards Syria (zone 4), the climate is desert, quite cold in winter, with frequent frosts, and hot in summer, but a bit less hot than the plains because of altitude. In Rutbah, 2,000 feet above sea level, the average is between 43.5 °F in January and 86 °F in July. In summer the temperature can sometimes reach 113/117 °F.
Average temperatures - Ar Rutbah
Ar RutbahJanFebMarAprMayJunJulAugSepOctNovDec
Ar RutbahJFMAMJJASOND
Min (°F)364146556472737368614641
Max (°F)525964778695999791826857

Throughout the year, only 4.8 in of rain fall, concentrated in the winter months; during winter. Snow and frost are possible during cold spells. Here is the average precipitation.
Average precipitation - Ar Rutbah
Ar RutbahJanFebMarAprMayJunJulAugSepOctNovDecYear
Ar RutbahJFMAMJJASONDY
Prec. (in)0.60.610.80.400000.20.60.64.7
Days66653100034539

In the rest of Iraq, which is flat or hilly (zones 2 and 3), the climate is arid, mild in winter and scorchingly hot in summer. Summer goes from June to September, but the months of May and October are still very hot. Compared with other desert and depopulated areas, in Mesopotamia the landscape changes locally, only because the rivers can create wetlands, and they also allow for irrigation in large areas.
-In the northern region (zone 2) the climate is arid, but in the cold half of the year, for a few months there can be the passage of fronts, with moderate rainfall. In Mosul, located on the northern plain, on the banks of the Tigris River, not far from the ancient Nineveh, the winter is mild, but certainly it's not tropical: the January average is 44.5 °F. From December to March it rains for 7/10 days per month, and sunny days alternate with periods of bad weather. At night it often gets cold, and sometimes the temperature can drop a few degrees below freezing. The summer in Mosul is very hot, with a relentless sun, and with daytime temperatures of 109 °F in July and August, but with peaks of 117/118 °F; fortunately, however, the air humidity is low.
Average temperatures - Mosul
MosulJanFebMarAprMayJunJulAugSepOctNovDec
MosulJFMAMJJASOND
Min (°F)363745526170777566574539
Max (°F)5459667791102109109100887057

Throughout the year, in Mosul, 14.3 in of rain fall: they are not many, but they are concentrated between November and April, with very few rains in May and October, while between June and September it almost never rains. Here is the average precipitation.
Average precipitation - Mosul
MosulJanFebMarAprMayJunJulAugSepOctNovDecYear
MosulJFMAMJJASONDY
Prec. (in)2.42.62.61.80.600000.41.82.414.4
Days111112960000571071

South-east of Mosul, Kirkuk has a similar climate, because the more southern position is balanced by the slightly higher altitude, that is, 1,150 feet.

Nineveh Gates

-Throughout the south-central Iraq (zone 3) the climate is desert or semi-desert, with mild winters, and becomes progressively warmer as you head south; summers are very hot. Fortunately, even in this area the relative humidity during the summer months is low, because the prevailing winds, often lively and sometimes capable of generating dust storms, come from the west or north-west and therefore from the continent. The wind is more frequent in the south central part of the country.
In the Iraqi capital Baghdad, the average temperature goes from 49 °F in January to 95 °F in July, with average highs of 111 °F. Here too summer is hot and the sunshine reigns supreme, with peaks of around 120 °F: these temperatures make Baghdad one of the hottest capitals in the world. In winter, days are mild but nights are often cold, and the temperature may drop a few degrees below freezing. Here are the average temperatures.
Average temperatures - Baghdad
BaghdadJanFebMarAprMayJunJulAugSepOctNovDec
BaghdadJFMAMJJASOND
Min (°F)394350596873797770614841
Max (°F)6166758699106111111104917563

Throughout the year, only 6 in of rain fall, almost all from November to March; from June to September it never rains. Here is the average precipitation.
Average precipitation - Baghdad
BaghdadJanFebMarAprMayJunJulAugSepOctNovDecYear
BaghdadJFMAMJJASONDY
Prec. (in)111.20.60.300000.10.815.9
Days44431000013424

Baghdad

In the near cities of Kerbala and Ramadi, the climate is similar to that of Baghdad.
Further south, the temperatures rise a bit in winter: in Basra and Nasiriya the average goes from 52 °F in January to 96 °F in July. On the coast of the Persian Gulf it reaches 53.5 °F in January. However, even the south during winter may experience some slight frosts at night. The rainfall in the south goes down to only 4 inches per year, a value typical of a desert climate.
Average temperatures - Nasiriya
NasiriyaJanFebMarAprMayJunJulAugSepOctNovDec
NasiriyaJFMAMJJASOND
Min (°F)434654647579828175665546
Max (°F)63687790102109113113108957966

In Basra, the summer humidity remains quite low, but it rises a little compared with other cities, not because of the proximity of the sea, but rather because of the presence of wetlands in the area: in July the humidity in the afternoon rises to 23%, compared with 10% in Baghdad, and 11% in Nasiriya. Since the prevailing wind comes from the north-west, even in Al-Faw, located on the coast, the air in summer is often dry.

The Persian Gulf is very cool for swimming in winter, while in summer it becomes very warm, exceeding 85 °F for a few months.
Sea temperature - Al-Faw
Al-FawJanFebMarAprMayJunJulAugSepOctNovDec
Al-FawJFMAMJJASOND
Sea (°F)666364707984889088847972

The south-western area of Iraq has a desert climate, and it's the driest area of the country, so that precipitation drops to about 2 inches per year; the area is practically depopulated, because the population is concentrated from ancient times in Mesopotamia, the valley between the two rivers, Euphrates and Tigris.

Between the end of winter and the spring, Iraq can be affected by strong southerly winds, which may give rise to dust storms; these winds may occur even in autumn and winter, though more rarely. On the contrary, during the long summer months, the shamal blows, a moderate northwesterly wind, dry and torrid, which may cause rapid dehydration, and when it's more intense, it can raise dust or sand as well.

When to go

From the point of view of the temperatures, the best times to visit Iraq are spring and autumn: in the north, below 3,300 feet, in cities like Mosul and Sulaymaniyah the best months are April and from mid-October to mid-November, while in the center and south (see Baghdad, Basra), they are March and November: this way you avoid both the scorching summer and the possible cold in winter. Sometimes, however, in these periods it can rain, especially in the north. In May and October the temperatures are already well above 85 °F, and can already approach 105 °F, but on the other hand it almost never rains.

What to pack

In winter: in the north and north-west (Mosul, Nineveh, Rutbah): warm clothes, jacket, hat, raincoat or umbrella, scarf; in the mountains of Kurdistan, mountain and snow outfit, warm boots; in the center and south (Baghdad, Basra), spring/autumn clothes, a jacket and a sweater, hat for cold nights.

In summer: in the whole country at low altitude, from north to south: lightweight, loose fitting, light-colored clothing, light and long shirt and pants of natural fibers (cotton, linen), sun hat, desert turban; in the north and north-west (Mosul, Nineveh, Rutbah), you can bring a light sweatshirt for the night and early morning. In the mountains of Kurdistan, light clothes for the day, sun hat or desert turban, sweatshirt or sweater for the evening, a jacket for the highest peaks; hiking shoes.