Sikkim in May sits in a specific window: the last reliably dry weeks before monsoon, peak rhododendron tail in the high valleys, and the most crowded month of the year because of Indian school holidays. Gangtok daytime temperatures range 19 to 22°C, North Sikkim is fully open with the Lachen-Gurudongmar circuit at full capacity, and prices climb 30 to 40 per cent above shoulder rates. I have run May trips every year since 2012 and the pattern is consistent: the weather is beautiful, the hotels are packed, and the guests who book by late February have a much better trip than the guests who book in April.
May weather across Sikkim
Gangtok (1,650 m) sees daytime highs of 19 to 22°C and overnight lows of 12 to 15°C — the most comfortable city-level weather of the year. Pelling (2,150 m) runs 2-3°C cooler. Lachung and Lachen at 2,750 m see daytime 14-18°C and chilly nights of 6-10°C. Gurudongmar Lake at 5,430 m has its highest pre-monsoon temperatures — 8 to 12°C at the lake at 9 a.m. Rainfall starts climbing through the month: first half is dry, second half sees afternoon thunderstorms more frequently, and the monsoon onset happens any time between 15 and 25 May depending on the year.
What is open in May
- North Sikkim — fully open and at peak season. Lachung, Lachen, Yumthang, Zero Point, Gurudongmar all accessible.
- Old Silk Route — open but pre-monsoon, with some afternoon visibility loss at Thambi View Point in second half
- Singalila / Sandakphu trek — second-best window of the year (after October), full rhododendron bloom on the ridge
- Goecha La trek — peak window for the approach to Kanchenjunga south face
- All monasteries — Rumtek, Pemayangtse, Enchey, Tashiding, Yuksom Dubdi
- Tea garden tours — Temi (Sikkim), Happy Valley/Glenburn/Makaibari (Darjeeling) all in second-flush prep
The late rhododendron bloom
May is the upper-altitude rhododendron tail. The lower-valley species (R. arboreum, R. dalhousiae) have already bloomed in March-April. May is when the high-altitude species — R. anthopogon, R. setosum, R. lepidotum — bloom at 3,500 to 4,500 metres. Yumthang Valley peaks in the first two weeks of May for the famous mass bloom; Shingba Sanctuary above Yumthang holds bloom through mid-May. Barsey on the Singalila ridge peaks late April to mid-May. If rhododendrons are the reason for your trip, target the first 15 days of May.
The crowd and price reality
Indian school summer holidays usually run from the first week of May to mid-June. Family travellers from across India arrive in waves. By 10 May, MG Marg is at maximum capacity in the evenings. Tsomgo Lake on a Saturday in May has 60+ vehicles parked. The road from Gangtok to Lachung takes an extra hour because of bus traffic at Mangan. Hotel rates climb 30 to 40 per cent above November shoulder rates. Mid-range Gangtok hotels (Summit Golden Crescent, Denzong Regency) move from ₹6,500 to ₹9,500 a night. North Sikkim Bhutia lodges go from ₹3,500 to ₹5,500 with full meals.
What we tell people to skip in May
Tsomgo Lake on a Saturday or Sunday — the parking is chaotic, the yak-ride queues are 30 minutes long, the lake itself is hard to photograph without crowds. Shift to Monday or Tuesday if you can. Tiger Hill sunrise in Darjeeling in May — clear-view probability drops to 35 per cent because of pre-monsoon haze. October-November is dramatically better. Rumtek Monastery any time after 10 a.m. — same as year-round, but worse in May because the bus tour count is higher. Stick to our 5:30 a.m. dawn visit.
What to pack
- Daytime: light shirts, cotton trousers or jeans, comfortable walking shoes — Gangtok 22°C in May is genuinely warm
- Evening: a light fleece or windbreaker — MG Marg cools quickly after 7 p.m.
- High altitude (Gurudongmar, Zero Point): full down jacket, gloves, beanie, thermal base layer — you need them at altitude regardless of season
- Rain gear: a packable rain shell — second-half May thunderstorms are real
- Sunscreen and sunglasses: UV at altitude is intense even in cloud
- Camera: peak rhododendron bloom is the photographer's reward for tolerating crowds