If you are traveling to Somalia, the security situation will govern your timing far more than the weather. That said, climate is worth factoring in.
December to February is the most comfortable period across most of the country. The long dry season (Jiilaal) brings cooler temperatures, lower humidity, and passable road conditions. Mogadishu averages around 27°C in January. This is widely considered the best time to visit.
April to June brings the Gu rains, Somalia's main rainy season. Inland roads become muddy or impassable. The landscape turns green and dramatic, but travel becomes harder. The coast remains accessible.
July to September is hot and dry in the south, with the southwest monsoon bringing strong winds and rough seas along the Indian Ocean coast. The northern regions (Puntland) are extremely hot and humid during this period.
October to November brings the shorter Dayr rains. Conditions are similar to the Gu but less severe.
Ramadan affects operating hours, restaurant availability, and the general pace of life. Traveling during Ramadan requires more flexibility but also offers the chance to witness Somali communal life at its most vibrant, particularly the evening iftar meals.