The best time to visit Nouakchott is November to February, when daytime temperatures sit between 25 and 32 °C, nights are pleasantly cool, and the harmattan wind has not yet become dangerously hot. This is also when migratory birds peak at Banc d'Arguin, and the fishing beach is at its most active.
March to May sees temperatures climbing rapidly toward 38–42 °C, with occasional dust storms. It is manageable but physically demanding. June to October is the off-season: searing heat (regularly above 40 °C), very high humidity near the coast, and — in August and September — the brief but intense rainy season that can flood unpaved streets. Accommodation prices drop significantly in the hot season, and the city is quieter, but travel is uncomfortable without strong air conditioning.
For desert excursions to Chinguetti or the Adrar Plateau, November to January is absolutely the ideal window: cool enough for camping, clear skies, and manageable driving conditions on piste tracks.