In Mauritania, the climate, hot and desert in the centre-north, becomes semi-desert in the south, due to the summer monsoon, which brings some rainfall between June and early October. On the coast the heat is tempered by sea breezes, but the climate is mild only in the northernmost part, which is also affected by a cool sea current. Across the country, wind can bring sandstorms.



The north (zone 1 on the map) is occupied by the western part of the Sahara desert; along the coast, however, a cold current flows, so that the sea temperature reaches a maximum of 24 °C (75 °F) in August and September in the north; the cold current affects the climate in the northern part of the coast, to the point that in Nouadhibou, the air is often mild or pleasantly warm: the daily average is 20 °C (68 °F) in winter, when there are frequent morning mists, it is still about 23 °C (73 °F) in July, and reaches 25 °C (77 °F) in September, which is the warmest month. However, when the wind blows from the desert, the temperature can rise by several degrees and reach 37/38 °C (99/100 °F) for most of the year (except in winter), however, these heatwaves are less intense than in the rest of the country. However, the months in which hot days are more frequent are September and October.
Here are the average temperatures of Nouadhibou.
Average temperatures - Nouadhibou

Nouadhibou	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Nouadhibou	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	15	15	16	16	17	18	19	20	21	19	17	15
Max (°C)	23	24	25	25	25	26	26	27	28	28	26	23
Min (°F)	59	59	61	61	63	64	66	68	70	66	63	59
Max (°F)	73	75	77	77	77	79	79	81	82	82	79	73

In Nouadhibou the rains are definitely scarce, since they do not even reach 20 millimeters (0.8 inches) per year. The sun shines all year round, though a little less than in the inland areas, due to morning fogs and mists.
Sunshine - Nouadhibou

Nouadhibou	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Nouadhibou	J	F	M	A	M	J	J	A	S	O	N	D
Sun (hours)	7	8	8	9	9	8	8	8	8	8	8	6

As mentioned, the sea temperature in this northern part of the coast is very cool for much of the year, while it becomes warm enough for swimming from August to October.
Sea temperature - Nouadhibou

Nouadhibou	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Nouadhibou	J	F	M	A	M	J	J	A	S	O	N	D
Sea (°C)	19	19	19	19	19	20	22	24	24	23	22	20
Sea (°F)	66	66	66	66	66	68	72	75	75	73	72	68

In inland northern areas we are instead in full desert: winter is cooler, so that the daytime temperatures are around 20 °C (68 °F) in January, the warmest months are the "canonical" ones, July and August, with highs around 40/42 °C (104/108 °F); the hottest area is the north-east, where in summer the temperature can sometimes reach 50 °C (122 °F). The rains are definitely scarce.
Here are the average temperatures of Zouérat, located in the north, near the border with Western Sahara, and 350 meters (1,150 feet) above sea level.
Average temperatures - Zouérat

Zouérat	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Zouérat	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	12	15	16	18	20	23	26	27	26	22	18	14
Max (°C)	22	25	27	31	33	36	40	40	37	32	27	23
Min (°F)	54	59	61	64	68	73	79	81	79	72	64	57
Max (°F)	72	77	81	88	91	97	104	104	99	90	81	73

In Zouérat it almost never rains: in a year, 55 mm (2.1 in) of rain fall, with a maximum of 20 mm (0.8 in) in September.
In the desert the sun shines all year round, however there is a slight decrease in the sunshine hours in summer, when sometimes there may be some clouds.
Sunshine - Zouérat

Zouérat	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Zouérat	J	F	M	A	M	J	J	A	S	O	N	D
Sun (hours)	9	9	10	11	11	10	10	10	9	9	9	8

The south-central region is that of the Sahel (zone 2), which in the summer months is affected by the northern offshoots of the African monsoon, which brings clouds and rains from the Atlantic Ocean.
The Mauritanian capital Nouakchott, located in the central-southern part of the coast, is warm all year round; in winter, from December to February, highs remain around 29/30 °C (84/86 °F), but nights are cool. In addition, in winter the Harmattan, the dry north-east wind, often blows, carrying dust and sand. In March, the temperature increases, though not as much as in the rest of the country, thanks to the influence of the ocean; however, the daytime temperature rises up to 33 °C (91 °F) in June, which is the hottest month. In fact, the temperature can reach 45 °C (113 °F) when the wind blows from inland, which can even cause sandstorms. From July to September it's the period of the monsoon, which lowers the maximum temperature to 30/32 °C (86/90 °F), but in return increases moisture, and brings some rainfall, with a peak in August. However, in Nouakchott the influence of the monsoon is limited, so that the rains are still at desert levels. Here is the average precipitation.
Average precipitation - Nouakchott

Nouakchott	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Nouakchott	J	F	M	A	M	J	J	A	S	O	N	D	Y
Prec. (mm)	1	1	1	1	1	1	20	80	40	10	5	1	160
Prec.(in)	0	0	0	0	0	0	0.8	3.1	1.6	0.4	0.2	0	6.3
Days	0	0	0	0	0	1	2	4	4	1	1	0	13

Even in midsummer the wet currents coming from the ocean have some breaks, during which the winds from the interior start to blow again, raising the temperature above 40 °C (104 °F). After the monsoon, during the month of September and in October, the temperature increases again, to the point that these are the hottest months, with highs generally around 35 °C (95 °F). Finally, in mid-November the temperature starts to decline, in view of winter. Here are the average temperatures in Nouakchott.
Average temperatures - Nouakchott

Nouakchott	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Nouakchott	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	15	16	18	18	20	22	23	25	26	23	20	16
Max (°C)	27	30	31	31	32	33	30	31	33	35	32	28
Min (°F)	59	61	64	64	68	72	73	77	79	73	68	61
Max (°F)	81	86	88	88	90	91	86	88	91	95	90	82

In Nouakchott too, the sun shines all year round, however in the summer cloud banks can pass, due to the monsoon.
Sunshine - Nouakchott

Nouakchott	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Nouakchott	J	F	M	A	M	J	J	A	S	O	N	D
Sun (hours)	8	9	9	10	9	8	9	9	8	9	8	7

The cool sea current has evident effects even at Nouakchott for most of the year, in fact the sea temperature is about 19 °C (66 °F) from February to May, it's still 21 °C (70 °F) in June, and becomes warm, reaching 26/27 °C (79/81 °F) only between August and October: given that the city is located south of the Tropic, these values are not so high.
Sea temperature - Nouakchott

Nouakchott	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Nouakchott	J	F	M	A	M	J	J	A	S	O	N	D
Sea (°C)	20	19	19	19	19	21	24	26	27	26	24	22
Sea (°F)	68	66	66	66	66	70	75	79	81	79	75	72

East of the capital, the heat is more intense for most of the year, excluding the winter months, due to the distance from the sea. In Tijikja, at 400 metres (1,300 feet) of altitude, in June the daytime temperature is normally about 39 °C (102 °F); annual precipitation amounts to 130 mm (5.1 in).
In the southern inland areas, winter is even warmer than in Nouakchott: night-time temperatures remain around 20 °C (68 °F) on the coast and drop to 17/18 °C (63/64 °F) in inland areas, while highs are around 28/30 °C (82/86 °F), the heat begins to increase already in February, and in May highs of 40/41 °C (104/406 °F) are normal, but then the summer monsoon is more intense, so that rainfall goes from 200 to 400 mm (8 to 16 in) per year. In Néma, 110 mm (4.3 in) of rain fall in August. The combination of moisture and temperature, which remains around 36 °C (97 °F) during the rainy months, makes the heat uncomfortable.
Here are the average temperatures of Kiffa, located in the south of the country, 500 kilometres (310 miles) away from the sea.
Average temperatures - Kiffa

Kiffa	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Kiffa	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	17	18	22	26	29	30	28	27	27	26	21	17
Max (°C)	28	32	35	39	41	41	37	36	36	37	34	30
Min (°F)	63	64	72	79	84	86	82	81	81	79	70	63
Max (°F)	82	90	95	102	106	106	99	97	97	99	93	86

In the far south, along the border with Senegal (zone 3 on the map), the summer rains become even more abundant, so that the total is between 400 and 600 mm (16 to 23.5 in) per year: we are still in the Sahel, but in the climatic subdivision called "Sudanese", where even more than 200 mm (8 in) in August can fall, and in the rainy season the landscape changes, becoming definitely green. In Mauritania this happens especially in the southernmost region, called Guidimakha.
Here is the average rainfall of Sélibaby, the region's capital.
Average precipitation - Sélibaby

Sélibaby	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Sélibaby	J	F	M	A	M	J	J	A	S	O	N	D	Y
Prec. (mm)	0	0	0	0	5	50	110	160	120	25	2	0	475
Prec.(in)	0	0	0	0	0.2	2	4.3	6.3	4.7	1	0.1	0	18.7
Days	0	0	0	0	2	5	10	11	9	3	0	0	40

In the extreme south, winter is hot, and even in December and January, daytime temperatures exceed 30 °C (86 °F). Already in February the temperature exceeds 35 °C (95 °F), and spring is torrid, but then in summer the decrease is evident.
Average temperatures - Sélibaby

Sélibaby	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Sélibaby	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	16	19	22	25	28	27	25	25	24	24	20	17
Max (°C)	33	36	39	41	42	39	35	34	34	37	37	33
Min (°F)	61	66	72	77	82	81	77	77	75	75	68	63
Max (°F)	91	97	102	106	108	102	95	93	93	99	99	91

The best time to visit Mauritania is winter, from December to mid-February: temperatures are hot in the south and mild in the north, the sun shines and it almost never rains. At night it can get a bit cold everywhere, quite often in inland areas of the north, rarely in the south, while in the south it can sometimes be hot even in this season, but more rarely than in the rest of the year.
In winter it's also possible to swim in the sea, even though the sea is a bit cool, and sometimes the air can be cold, at least at night and in the early hours of the morning.


In winter: for inland areas, light clothing, long and loose-fitting shirt and pants, a scarf for the sand and dust, sunglasses (even graduated instead of contact lenses), a jacket and a sweater for the evening, especially in the north, desert boots or sandals; for Nouakchott and the coast, light clothes for the day, a sweatshirt and a jacket for the evening, scarf for the sand.
In summer: lightweight clothes, long and natural fabric (cotton or linen), desert turban, a sweatshirt for the night, sleeping bag for night outdoors. For women, it is best to avoid shorts and miniskirts. On the coast north of Nouakchott, a light sweatshirt; for the south, a light raincoat for the rain showers.