The best times to visit Darjeeling are October–November and March–May, when the skies are clear enough to see Kanchenjunga and the surrounding Himalayan peaks. October and November bring crisp air and sharp views; March and April bring the flowering of rhododendrons and magnolias in the botanical garden and surrounding forests, and the first flush of the tea season begins in late March.
Avoid June through September. The monsoon drenches the hills in almost continuous rainfall, the mountain views disappear entirely behind cloud, and the trails become slippery and leech-ridden. The toy train service is sometimes disrupted by landslides during this period.
December through February can be cold — temperatures drop near freezing at night and the upper ridges sometimes see frost. The views can be spectacular on clear winter mornings, and the town is quieter, but come prepared for cold.
The tea seasons are worth knowing if you want to buy: first flush (late March–April) is the lightest and most prized; second flush (May–June) is fuller-bodied; monsoon and autumnal flushes are available from August through November.