Victoria Falls, where they are located

In the area of the Victoria Falls, the climate is sub-tropical, with a mild and dry winter from mid-May to mid-August (during which, however, nights are cold), and a hot, muggy and rainy summer from mid-November to mid-March. The rains occur in the form of downpour or thunderstorm. Between September and November, before the rainy season, there is a hot period, in fact the hottest of the year, in which the temperature easily reaches 35 °C (95 °F), and sometimes even 40 °C (104 °F), even though the humidity is not as high as in summer. October is the hottest month of the year. On the contrary, in winter, when during the day the weather is nice, the temperature at night may approach freezing (0 °C or 32 °F).
Here are the average temperatures.
Victoria Falls - Average temperatures
Min (°C)191918151076914181919
Max (°C)303030302826262832343330
Min (°F)666664595045434857646666
Max (°F)868686868279798290939186

Precipitation is not abundant, since it amounts to 690 millimetres (27 inches) per year, but it is quite abundant from December to February, while it almost never rains from May to September.
Here is the average precipitation.
Victoria Falls - Average precipitation

The amount of sunshine in the Victoria Falls is very good from April to October, ie the dry season, while it is acceptable in the rainy season, in which, between a shower and the other, the sun shines.
Victoria Falls - Sunshine

108 metres (354 feet) deep and 1,700 metres (5,600 ft) wide, the Victoria Falls, probably the most spectacular in the world, are located on the border between Zambia and Zimbabwe, about 900 metres (3,000 feet) above sea level, and are formed by the waters of the Zambezi River. Due to the altitude, the heat is tempered in the hot season (September to March), while nights are cold in the period mid-May to mid-August. The falls can be accessed from both countries, although the most equipped part is that of Zimbabwe. The falls are a UNESCO World Heritage Site.
The season of high river discharge runs from February to May, with a spike in April. The river reaches its minimum flow in November, when it becomes ten times smaller than in April. When the flow rate is highest, you cannot see some parts of the falls because of splash and mist, and it is difficult to take pictures. During the period in which the flow rate is lower, from October to December, the waterfall is divided into several streams, and some parts become dry. In December, the river begins to grow again, but in this period we are in the rainy season, with a sultry heat and frequent afternoon showers.
The spray caused by the waterfalls exceeds 400 metres (1,300 feet) in height, and is visible from a distance of 50 km (30 mi); it also feeds a nearby rainforest.
The Victoria Falls National Park is home to a rich fauna, including elephants, giraffes and zebras.
You can go rafting in the rapids produced by the waterfalls. There is also a natural waterhole, the "Devil's Pool", where someone bathes on the edge of the falls, at least when the river flow is not at the highest level, however, this is a dangerous and not advisable activity.

Victoria Falls

When to go

The best time to visit the Victoria Falls goes from June to mid-August, being the coolest, as well as driest and sunniest, and in which the river flow rate is halfway between the minimum and the maximum. It is advisable to dress in layers, because nights are often cold, while during the day the air becomes mild or pleasantly warm. It can also be useful to bring a raincoat for the spray. From mid-August to mid-November, it's still the dry season, but it is a period in which the heat becomes intense, while the river becomes increasingly drier.