In Rwanda, the "land of a thousand hills", just south of the Equator, the climate is pleasantly warm because of the altitude all year round, with cool nights. In fact, most of the country is located on a plateau, around 1,500 meters (5,000 feet) above sea level. The altitude decreases below a thousand meters (3,300 feet) only in the westernmost part, along the Rusizi River, which marks the border with the Democratic Republic of the Congo and is therefore the only area where it can get hot, and the temperature can sometimes reach 35 °C (95 °F).

Precipitation ranges from 1,000 to 1,400 millimeters (40 to 55 inches) per year depending on area; there's a dry season from June to August (and July is the driest month) and a rainy season from September to May. On closer view, there would be two rainy seasons, caused by the zenith passages of the sun, from March to May and September to November. However, from December to February the decrease in rainfall is small, and it's just more pronounced in the north, where it drops below 100 mm (4 in) per month, so we cannot properly speak of dry season. Between the two rainy seasons, the more intense is the former, and the rainiest months are usually April and May, when precipitation reaches 150 mm (6 in) per month, or even more.

The capital, Kigali, is located at the center of the country, at 1,500 meters (5,000 feet) above sea level, and receives 950 mm (37.5 in) of rain per year, with a maximum in April and a minimum from June to August, when it almost never rains. From December to February, the rains are still quite frequent. Here is the average precipitation.
Kigali - Average precipitation

The rains in Rwanda usually occur in the form of downpours or thunderstorms, but there is not much sun, in fact the sky is often cloudy, although in the driest months, especially in June and July, the sun comes out more often.
Kigali - Sunshine

Temperatures are stable all year round, and hover around 26/27 °C (79/81 °F) during the day, and 15/16 °C (59/61 °F) at night. Here are the average temperatures.
Kigali - Average temperatures
Min (°C)161616161615151616161616
Max (°C)272727262626272828272626
Min (°F)616161616159596161616161
Max (°F)818181797979818282817979

In the east, the Akagera National Park is located around 1,300/1,400 meters (4,200/4,600 feet) above sea level. In the west, Lake Kivu is at 1,450 meters (4,757 feet).
In the cities located at higher altitudes (see Nyanza, Butare, Ruhengeri), the temperatures are a bit lower, and at night it's cool, if not a bit cold.
Here are the average temperatures of Ruhengeri (or Musanze), located in the north, 1,800 meters (5,900 feet) above sea level, near the Volcanoes National Park.
Ruhengeri - Average temperatures
Min (°C)111111131312111211111111
Max (°C)252524242323242424242424
Min (°F)525252555554525452525252
Max (°F)777775757373757575757575

Here, 1,200 mm (50 in) of rain fall per year, with a similar trend to that of Kigali (a more pronounced dry season from June to August, and a less pronounced one from December to February).
In the south, the decrease in rainfall from December to February is felt even less, so much so that there is only one rainy season from September to May, as you can see from the rainfall of Cyangugu, on the southern shores of Lake Kivu.
Cyangugu - Average precipitation

In Rwanda there are also mountainous areas, in particular in the north we find the Virunga Mountains, a volcanic chain whose highest peak is Mount Karisimbi, 4,507 meters (14,787 feet) high, located in the Volcanoes National Park. Along the mountain slopes, the sky is often covered with clouds. At medium-low altitude a cloud forest grows, while above 3,000 meters (9,800 ft) the climate is colder, the vegetation is sparser and the forest is replaced by shrubs, and at night the temperature can drop below freezing (0 °C or 32 °F). Finally, at high altitude we find a high-altitude desert.
South of the Virungas, the whole western area of the country is mountainous: in the west, in the Murambi province, the highest peaks reach 2,700 meters (8,900 ft), while in the south-west, in the Nyungwe Forest National Park, they reach 2,500 meters (8,200 ft). Above 2,000 meters (6,500 feet), at night it can get cold throughout the year.
In mountainous areas, rainfall is more abundant, and showers may occur throughout the year.

Landscape in Rwanda

Best Time

The best time to visit Rwanda runs from June to August, since it is the driest of the year. June and July are the best months, while usually from the second half of August the rains start to get a bit more frequent.

What to pack

In winter (June to August): bring spring/autumn clothes (light for the day), a sweater and a jacket for the evening, a sun hat, hiking shoes. For the Virunga Mountains, warm clothes, such as a down jacket, a hat, gloves.
In the rest of the year: bring spring/autumn clothes (light for the day), a sweatshirt, a raincoat, hiking shoes, a light jacket for the evening above 1,500 meters (5,000 feet). For the Virunga Mountains, warm clothes, such as a down jacket, a hat, gloves.