There are only two seasons across the Congos: dry and rainy, though depending on where you are, the times for these will change. In the rainforest the rainy season arrives like clockwork in the winter, from about October to April; frequent downpours and scattered clouds will greet the traveller, and could heed movement across the moist and muddy lowlands.
In general, through the northern belt of equatorial rainforest the rainy season runs from October to April, and in the Katanga region the rains come from December to March.
Monsoon rains are the norm, meaning short outbursts of rain that will last one or two hours and drench everything in sight. These tend to occur in the afternoon and early evening.
Temperatures in the plains of the south of DR Congo can be as much as 35°C in the summer, but averaging about 25°C across the rainforest, with heavy humidity. In the mountains along the east it can get cooler in the day and evening, sometimes going as low as 10°C.
The Congos have two seasons: dry and rainy. In the dry season the roads tend to be better for overlanding, though it can get hot and dusty at times. In the rainy season some roads may be impassable due to mud and flooding, so visits into the deep rainforest are usually done in the dry months.
There is an exception to this as the southern reaches of DR Congo are in the African savanna belt and experience a later rainy season, but can be oppressively hot in the summer.