Choluteca is in one of the hottest parts of Central America, and when to go depends largely on your tolerance for heat and rain. The dry season runs from November to April, with temperatures regularly hitting 35–38°C in March and April — the hottest months of the year. This is technically the "best" time in terms of travel conditions, but it is brutally hot.
The wet season (May to October) brings daily afternoon rain that breaks the heat briefly before the humidity rises. Travel is harder during this period due to flooded roads and river crossings, particularly in September and October. However, the surrounding countryside is green and the Choluteca River fills properly, making boat trips on the Gulf of Fonseca more worthwhile.
The most comfortable months are December to February — still warm, with less extreme heat and dry roads. This is when most travellers pass through on the Pan-American Highway. If you are visiting for the sea turtle nesting at Punta Ratón, July to December is the relevant season.