Provenance
Sources & method
Most Bhutan weather pages online are written from other Bhutan weather pages. This one is written from Bhutan’s own meteorological record, and every figure on the site traces back to a named source you can go and check. Here is exactly what we use, what we refuse to use, and what we know is due for a re-check.
The climate numbers
NCHM station normals, transcribed by hand
Every long-term average on this site — the monthly high/low and rainfall figures on the month pages, the best-time comparison table and the six-town grid on the forecast page — comes from a single source: the Climate Data Book of Bhutan 2018, published by the National Center for Hydrology and Meteorology (NCHM), Royal Government of Bhutan. The figures are 1996–2018 station normals for six stations: Thimphu, Paro, Punakha, Phobjikha, Bumthang and Phuentsholing.
They are transcribed exactly as published — not rounded, not smoothed, not gap-filled. Where the Climate Data Book doesn’t publish a value (monthly means for Phuentsholing, rain days for three of the six stations), the site shows nothing rather than an estimate. All 312 cells were re-checked against the source tables in a verification pass on 14 July 2026; 312 of 312 matched, and the annual totals were recomputed from the monthly figures rather than copied.
Elevations and coordinates for the six towns are the Wikidata values, verified the same day. Metres are authoritative throughout; any figure in feet is derived from the metres, never the other way round.
The live forecast
Model output, labelled as model output
The current conditions and 7-day outlook on the home and forecast pages come from Open-Meteo, requested live in your browser. We pass each town’s true valley-floor elevation with the request, because the ~9 km model grid smooths Himalayan terrain badly enough to put a valley floor hundreds of metres off without it.
Two honest caveats. First, these are forecasts, not station readings — model output for a grid cell, not what a thermometer in Thimphu recorded. Second, the same models run systematically cool on Himalayan valley floors: a forecast high can sit a few degrees below what NCHM stations actually measure for that time of year. That is why the live numbers and the climate normals are never presented as a comparison on this site, even though they sit on the same page.
What we won’t publish
The refusals matter as much as the sources
- Reanalysis rainfall. ERA5 and the Open-Meteo historical archive are widely used for “average rainfall” figures — and in Bhutan they are unusable. The reanalysis precipitation disagrees with the ground stations badly enough that we derive no rain figure from it anywhere on this site. Every millimetre you read here is a station measurement.
- Statistics without a source. A number that can’t be traced to a named publication stays out. Notably absent: Paro flight diversion and cancellation percentages. They are quoted confidently all over the web and we could not source a single one, so the Paro page explains the mechanism instead of inventing a rate.
- Cheap-season pricing as an “SDF discount”. Bhutan’s Sustainable Development Fee is flat year-round. Monsoon and winter travel can be cheaper in hotels and flights — never in the government fee — and framing it otherwise misleads people planning a budget.
- Legend presented as fact. Where a story is told as tradition in Bhutan rather than established as history, it is labelled as tradition on the page.
Corrections
Things we got wrong, or the internet has
A verification pass in July 2026 re-checked the site’s claims against primary sources and overturned several that are repeated widely elsewhere:
- “October is Bhutan’s busiest month” — false. Department of Tourism arrival figures make May the biggest month. Autumn wins on weather, not on crowds; if you came here to avoid people, that changes the answer.
- The elevation lapse rate. Corrected to roughly 5 °C cooler per 1,000 m climbed, measured at Bhutan’s own stations rather than the textbook global figure often quoted.
- Black-necked crane counts were updated to the current RSPN winter totals, and the Paro approach-procedure attribution was corrected to its actual source.
Standing re-checks
What has a shelf life
Some figures are true today and won’t be indefinitely. These carry visible reconfirm notes on the pages that use them, and they sit on a standing re-verification list:
- Festival dates are lunar and shift every year. 2026 tshechu dates are confirmed; 2027 dates conflict between operators with no official calendar published yet. Always reconfirm against bhutan.travel before booking around one.
- The Sustainable Development Fee rate is stated valid until 31 August 2027.
- Crane counts and tourism arrival statistics are refreshed when RSPN and the Department of Tourism publish new totals.
- Pilot numbers and Paro airport infrastructure details are flagged for re-checking against primary aviation sources rather than press coverage.
Found something that looks wrong? It probably is — tell us and we will check it against the source rather than defend it.
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