Kandahar has a semi-arid climate with very hot summers and cold winters. Temperatures in July and August regularly exceed 40°C; December and January see frost and occasional snow. Spring — March to May — and autumn — September to November — are the most comfortable seasons, with warm days and cool nights.
The pomegranate and grape harvest in September and October is when the Arghandab valley is at its most productive and the city's fruit stalls are fullest. If you are travelling specifically to understand the agricultural heartland of southern Afghanistan, this is the season to choose.
Security conditions rather than climate will typically determine when it is possible to visit. No season is inherently safe; all travel should be assessed against current conditions at the time of planning.