The Samburu National Reserve has an arid and semi-arid climate characterized by hot, dry days and cold nights and with a moisture level between 42 and 57, this indicates that the evapotranspiration is more than the available moisture.
The season of the long rains is from April to May, while the small rainy season runs from mid-October to mid-December, but usually the rains are concentrated in November; while the dry season runs from June to early October and January to March.
The long dry season from late June to October and the short dry season from December to March are the best times to travel to the reserve for wildlife observation.
The lack of rain and the hot sun quickly dry up the land and drain a lot of water reserves; then the animals are concentrated around the only permanent sources of water, like the Ewaso Ngiro river, where they can find water and food they need to survive; during this time, the vegetation is generally poor and this further facilitates the sightings.
The months from late October to April are the best for bird watchers because, in addition to the many resident species, also the birds that migrate here from Europe and Asia to escape palearctic winter are found in the park
The months coinciding with the rainy seasons are the best time for those who love greenery, in these periods in fact, thanks to rainfall, the park comes to life, the grasslands turn green and the trees and the bushes become lush; but, as a consequence to the rains, park roads can become difficult to get to.