Why the spring window specifically — and why nine nights
The autumn window gets the standard photographer's recommendation for Bhutan, and rightly — the clear post-monsoon skies are unmatched. But spring is the better window for a particular subset: cherry blossom along the Paro Chhu in late March (the Bhutanese pink-and-white that few photographers outside the country have shot at scale), rhododendron in the Dochu La ridge and the higher passes through April (the country's national flower; substantial stands in the buffer zones of the protected areas), and the Paro Tshechu at Rinpung Dzong — the country's most internationally-attended festival — typically falling early-to-mid April with the pre-dawn unfurling of the thongdrel as the photographic peak of any Bhutanese trip. The nine-night version covers all three, with three nights deliberately placed at Paro to give you the festival in full.