Tonight's frost risk and today's fog, hour by hour, read from the forecast on the published Met Office frost and WMO fog scales — for the roads and the terraces.
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Sa Pa's weather question isn't 'is it hot' — it's frost and fog. This page reads the forecast for frost risk on the high ground and for fog that drops visibility on the roads and leaves the streets grey, in plain words. It's a modelled estimate, not a measurement.
No frost expected today. Fog likely before 4 am.
As of 10 July at 4:07. Modelled forecast for the area around central Sa Pa (around 1,560 m), refreshed about every half hour.
| Day | Lowest temp | Frost risk | Worst visibility |
|---|---|---|---|
| Saturday 11 July | 17°C | No frost | Fog |
| Sunday 12 July | 18°C | No frost | Fog |
A modelled estimate, not a measurement
Frost uses the UK Met Office frost definitions, applied to the forecast minimum air temperature: Ground-frost risk when the low is between 0 and 4 °C (surfaces can still cool below the air on a clear, calm night), Air frost when the air itself reaches 0 °C or below, and we call the coldest nights — around −2 °C and below — Hard frost.
Fog uses the standard WMO and Met Office fog definitions, applied to the modelled visibility: Mist from 1 to 5 km, Fog below 1 km, and Dense fog below 200 m. The number is the model’s visibility for the area, not a reading on your road.
Here the real driving hazards are fog and frost, not heat. Fog can drop visibility to a few hundred metres on the Ô Quý Hồ and Lào Cai bends, and frost ices the road on cold nights. When fog or frost is flagged, slow right down and use low beams.
Frost (băng giá) can burn tender vegetables, flowers and young black cardamom on the high ground. A frost night is the time to cover or bring in what you can.
Frost forms on Sa Pa's high ground during the December–January cold spells, and ice or thin snow occasionally reaches the Fansipan summit and the Ô Quý Hồ pass. Snow here is rare and, by recent reporting, getting rarer.
Source: Climate of Sa Pa, checked 2026-06-15
Sa Pa sits in cloud for much of the year. Mornings and evenings often close in even in summer, leaving the streets grey and the passes hard to see. This page reads the forecast fog as well as the cold, so it stays useful in every season.
Fetched 10 July at 4:07. These are modelled estimates for the area around central Sa Pa (around 1,560 m), not measurements — a frost pocket or a fog bank on one slope won’t show in an area-wide number. Weather data by Open-Meteo (CC BY 4.0). Frost categories from the UK Met Office; fog bands from the WMO and Met Office.