Hi there,
Zambia's rainy season is mainly between the months of December and March so, usually April and May is the better time to go in terms of weather and prices.
If you intend to travel during the months of June to August, you will be traveling in high season which is when prices tend to shoot up and accommodation prices go up.
The weather in September, October and November can get very hot and dry although if you are planning a
safari tour these months would offer the best time to do so.
Hope this helps
VacationBuddy