Tanzania has two major seasons. Although weather patterns can vary widely from year to year typically, the dry season starts around June and last through until October and the green or rainy season commences from November until around May with a short dry season typically between January and February.
The parks located in the popular northern safari circuit are located at a high elevation making the climate pleasant for game viewing even during midday. The average temperature in the Serengeti during the warmer months of October to March can range from a high of 29C to a low of 17C and during the colder months of April to September a high of 26C to a low of 13C. The rim of the Ngorongoro Crater has an elevation of over 2,200 meters and the night time temperatures can drop below freezing. It is always advisable to bring warmer jumpers or a light jacket for evenings and early mornings.