Map from Google - Mauritania

In Mauritania, the climate, hot and desert in the centre-north, becomes semi-desert in the south, due to the summer monsoon that brings some rains 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, the wind can bring sandstorms.

Climatic zones in Mauritania

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 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 in winter, when there are frequent morning mists, it is still about 23 °C in July, and reaches 25 °C in September, which is the warmest month. However, when the wind blows from the desert, the temperature can rise and reach 37/38 °C for most of the year (except in winter), but it's still better than in the rest of the country.
Here are the average temperatures of Nouadhibou.
Average temperatures - Nouadhibou
Min (°C)151516161718192021191715
Max (°C)232425252526262728282623

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
Sea (°C)191919191920222424232220

In the inland northern areas we are instead in full desert: winter is cooler, so that the daytime temperatures are around 20 °C in January, the warmer months are the "canonical" ones, July and August, with highs around 40/42 °C; the hottest area is the north-east, where in summer the temperature can sometimes exceed 50 °C. The rains are definitely scarce.
Average temperatures - Bir Moghrein
Bir MoghreinJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)121316171820252524201713
Max (°C)212326273033383935302622

Mauritania, desert

The central-southern region is that of the Sahel (zone 2), which in the summer months is affected by the northern offshoots of the African monsoon, with come chance of clouds and rains moving inland from the Atlantic Ocean.
The Mauritanian capital Nouakchott is warm all year round; in winter, from December to February, the maximum temperatures remains around 29/30 °C, even though in this season the 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 in the rest of the country, thanks to the influence of the ocean, however, the daytime temperature rises up to 33 °C in June, the hottest month. In fact, the temperature can reach 45 °C when the wind blows from inland, and it can even cause sandstorms. From July to September it's the period of the monsoon, which lowers the maximum temperature to 30/32 °C, but it increases moisture, and brings some rains, with a maximum in August. Here is the average precipitation.
Average precipitation - Nouakchott
Prec. (mm)1111112080401051160

In fact, even in summer the wet ocean current have some breaks, during which the winds from the interior return to blow, bringing the temperature above 40 °C. After the monsoon, in September and October the temperature increases to the point that these are the hottest months, with highs generally around 35 °C. Finally, by mid-November the temperature starts to decline, in view of winter. Here are the average temperatures in Nouakchott.
Average temperatures - Nouakchott
Min (°C)151618182022232526232016
Max (°C)273031313233303133353228

The cold sea current has evident effects even at Nouakchott for most of the year, in fact the sea temperature is about 19 °C from February to May, it's still 21 °C in June, and becomes warm, reaching 26/27 °C only between August and October: given that the city is located south of the Tropic, it's still not much.
Sea temperature - Nouakchott
Sea (°C)201919191921242627262422


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 of altitude, in June the daytime temperature is normally about 39 °C. The annual precipitation amounts to 130 mm.
In the south, winter is even warmer than in Nouakchott: night-time temperatures remain around 20 °C on the coast and drop to 17/18 °C in inland areas, while highs are around 28/30 °C, the heat begins to increase in February, and in May highs of 40/41 °C are normal, but then the summer monsoon is more intense, so that in total, from 200 to 400 mm per year fall. In Néma, in August 110 mm of rain fall. The combination of moisture and temperature, which remains around 36 °C during the rainy months, makes the heat annoying.
Average temperatures - Kiffa
Min (°C)171822262930282727262117
Max (°C)283235394141373636373430

In the far south, along the border with Senegal (zone 3 on the map), the summer rains become more abundant, so that they total between 400 and 600 mm per year: this is still a part of the Sahel, but the climatic subdivision called "Sudanese", where even more than 200 mm in August fall, and in the rainy season the landscape changes, becoming definitely green. In Mauritania this happens especially in the southernmost region, called Guidimakha.


When to go

The best time to visit Mauritania is winter, from December to mid-February: the 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 little cold everywhere, quite often in the inland areas of the north, rarely in the south, while in the south it can sometimes be hot even at this time, but more rarely than in the rest of the year.
In winter it's also possible to swim in the sea, even though the water is a bit cool, and sometimes the air can be cold, at least at night and in the early hours of the morning.

What to pack

In winter: for inland areas, light clothing, long 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.