The Tibesti Mountains are within the Sahara Desert. Temperatures vary enormously by season and by altitude. The best expedition window is November through February, when daytime temperatures are tolerable (15–25°C at altitude) and nights are cold but manageable. The Saharan summer (June–September) brings temperatures exceeding 45°C in the lowlands, making travel extremely dangerous.
Even in the cooler season, be prepared for cold nights at altitude — temperatures at 3,000m can fall below 0°C. Wind and dust storms (haboobs) can arrive with little warning and reduce visibility to zero for hours. All expedition supplies, including water, must be self-sufficient.
Sandstorms are most frequent in spring (March–May) when the harmattan wind blows from the northeast. Avoid this period.