Short version: June to October for classic big-game viewing, December to February for birds, babies and low rates. March to May is the rainy low season, when most camps close.
If you only want the answer
June to September. July here is genuinely rainless, 0 mm on the thirty-year average, against 181 mm in January. Nothing concentrates animals like water that has stopped falling.
PrimeDry but hotShoulderGreen seasonBar height is average rainfall, the figure above it is the daytime high.
The year, season by season
The periods below are how this park actually divides its year, with thirty-year climate averages against each month. Averages hide bad years: a dry January still happens, and so does a wet July.
June – July
Prime
Dry season begins; coolest months (days ±30°C, nights down to 8°C. Pack warm layers for morning drives). Bush thinning, game viewing improving fast. Wild dog denning season starts.
June27.8° day, 15.8° night1 mm, and rarely a whole wet day
July27.5° day, 15.2° nightNo rain on the average
August – October
PrimeShoulder
Peak season. Wildlife crowds the shrinking river pools; predator action at its best. October turns properly hot (to 40°C). Balloon safaris run in this window.
August28.5° day, 16.0° nightNo rain on the average
September30.6° day, 17.5° nightNo rain on the average
October32.5° day, 19.4° night3 mm, and rarely a whole wet day
November
Shoulder
Shoulder month: game viewing still strong, first rains possible, low prices and almost no visitors.
November32.4° day, 20.4° night32 mm over 5 wet days
December – February
Green season
Green season: landscape transforms, newborn animals everywhere, and birding peaks as migrants arrive (Eleonora's falcon Dec–Jan). Hot, with rain showers. Excellent lodge rates.
December28.6° day, 19.7° night162 mm over 20 wet days
January27.7° day, 19.3° night181 mm over 22 wet days
February27.3° day, 19.1° night179 mm over 18 wet days
March – May
Green seasonShoulder
The long rains. Most camps close (typically March through May); black-cotton roads get difficult; malaria risk peaks. The park stays open and the Iringa road is passable year-round. This is the specialist's season, not the first-timer's.
March28.0° day, 19.1° night135 mm over 15 wet days
April28.1° day, 18.8° night45 mm over 7 wet days
May28.2° day, 17.5° night5 mm over 1 wet day
Climate figures are Open-Meteo climate normals, 1991 to 2020, measured at -7.3, 34.8. Prime, shoulder and green are worked out against this park's own year, not a fixed threshold: the four months with the least rain, the four with the most, and the rest in between. Full charts on the weather page.
The pattern
Ruaha has a single rainy season, roughly late November to May, and a long bone-dry stretch from June to October. As the dry season deepens, the bush thins out and wildlife concentrates on the Great Ruaha River and the last remaining pools, which is exactly what makes August to October so spectacular for predators.
Unlike Tanzania's northern parks, Ruaha's park fees don't change with season: the lower green-season prices you'll see are lodge rates, not TANAPA discounts.
Which camps stay open?
Almost everything inside the park closes for the April–May rains. The exceptions: Ruaha River Lodge and the TANAPA bandas stay open year-round, Mwagusi operates most of the year, and every lodge outside the gate (Tandala, Hilltop, Tungamalenga, Chogela) runs all twelve months. If you must travel in the rains, that's your shortlist. See the lodges page for details.