Lạng Sơn weather in May
In May, Lạng Sơn sees average daytime highs of 29°C and overnight lows near 23°C, with 221 mm of rain across 21.2 wet days and about 13 hours of daylight. It is the 5th-warmest and 4th-wettest month of the year here.
Highs climb over the month, from about 28°C in the first days to 30°C by the end. The sky is clear or mostly clear about 10% of the time in May, and the air most often feels oppressive.
Daylight stretches from about 12 h 48 min at the start of May to 13 h 12 min by month's end. Set against the rest of the year, May is Lạng Sơn's 5th-clearest and 6th-windiest month. For the whole year in context, see Lạng Sơn's year-round climate.
- Daytime high
- 29°
- 5th warmest
- Overnight low
- 23°
- 8th coldest
- Rainfall
- 221 mm
- 21.2 wet days
- Daylight
- 13 hours
- 5:18 AM – 6:20 PM
- Cloud cover
- 77%
- 5th clearest
- Wind
- 10 km/h
- 6th windiest
- Solar energy
- 4.61 kWh/m²
- Travel score
- 4.0
- out of 10
Lạng Sơn is provincial city of Vietnam.
- Density
- 2,533/km²
- people per km²
- Founded
- 2002
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in May
Highs climb over the month, from about 28°C in the first days to 30°C by the end.
A typical May day in Lạng Sơn reaches about 29°C in the afternoon and slips back to 23°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 33°C. Set against its neighbours, May runs about 3°C warmer than April and about 1°C cooler than June.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 28 | 28 | 28 | 28 | 28 | 28 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 |
| Avg low (°C) | 22 | 22 | 22 | 22 | 22 | 22 | 22 | 22 | 22 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 24 | 24 | 24 | 24 | 24 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| 1 | 28 | 22 |
| 2 | 28 | 22 |
| 3 | 28 | 22 |
| 4 | 28 | 22 |
| 5 | 28 | 22 |
| 6 | 28 | 22 |
| 7 | 29 | 22 |
| 8 | 29 | 22 |
| 9 | 29 | 22 |
| 10 | 29 | 23 |
| 11 | 29 | 23 |
| 12 | 29 | 23 |
| 13 | 29 | 23 |
| 14 | 29 | 23 |
| 15 | 29 | 23 |
| 16 | 29 | 23 |
| 17 | 29 | 23 |
| 18 | 29 | 23 |
| 19 | 29 | 23 |
| 20 | 29 | 23 |
| 21 | 29 | 23 |
| 22 | 29 | 23 |
| 23 | 29 | 23 |
| 24 | 30 | 23 |
| 25 | 30 | 23 |
| 26 | 30 | 23 |
| 27 | 30 | 24 |
| 28 | 30 | 24 |
| 29 | 30 | 24 |
| 30 | 30 | 24 |
| 31 | 30 | 24 |
How May really feels in Lạng Sơn
Once humidity and wind are folded in, May averages 17 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.
The story in May is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Lạng Sơn weather by month
How May compares with the rest of the year at a glance. May is the 5th-warmest and 4th-wettest month here — the current month is highlighted below.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 17° / 11° | 57 | 11.1 | 10.8 | 5.1 |
| Feb | 19° / 13° | 44 | 10.1 | 11.2 | 5.6 |
| Mar | 21° / 16° | 79 | 14.4 | 11.8 | 5.5 |
| Apr | 26° / 20° | 97 | 14.9 | 12.5 | 5.5 |
| May | 29° / 23° | 221 | 21.2 | 13 | 4.0 |
| Jun | 30° / 25° | 257 | 23.6 | 13.3 | 3.0 |
| Jul | 31° / 25° | 270 | 24.9 | 13.2 | 2.9 |
| Aug | 30° / 24° | 285 | 25.3 | 12.7 | 3.0 |
| Sep | 29° / 23° | 164 | 18.3 | 12.1 | 4.2 |
| Oct | 27° / 20° | 75 | 10.9 | 11.5 | 6.4 |
| Nov | 23° / 16° | 50 | 7.9 | 11 | 7.1 |
| Dec | 19° / 12° | 45 | 8.2 | 10.7 | 6.3 |
Cloud cover in May
The sky is clear or mostly clear about 10% of the time in May.
Beyond those clear spells, partly cloudy skies cover about 12% of May, with mostly cloudy or overcast conditions the remaining 78%.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 24 | 24 | 25 | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 25 | 24 | 24 | 24 | 24 | 22 | 22 | 22 | 21 | 21 | 20 | 20 | 19 | 18 | 18 | 18 | 17 | 17 | 16 | 15 | 15 |
| Cloudier (%) | 76 | 76 | 75 | 74 | 74 | 74 | 74 | 74 | 74 | 75 | 75 | 76 | 76 | 76 | 76 | 78 | 78 | 78 | 79 | 79 | 80 | 80 | 81 | 82 | 82 | 82 | 83 | 83 | 84 | 85 | 85 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 24 | 76 |
| 2 | 24 | 76 |
| 3 | 25 | 75 |
| 4 | 26 | 74 |
| 5 | 26 | 74 |
| 6 | 26 | 74 |
| 7 | 26 | 74 |
| 8 | 26 | 74 |
| 9 | 26 | 74 |
| 10 | 25 | 75 |
| 11 | 25 | 75 |
| 12 | 24 | 76 |
| 13 | 24 | 76 |
| 14 | 24 | 76 |
| 15 | 24 | 76 |
| 16 | 22 | 78 |
| 17 | 22 | 78 |
| 18 | 22 | 78 |
| 19 | 21 | 79 |
| 20 | 21 | 79 |
| 21 | 20 | 80 |
| 22 | 20 | 80 |
| 23 | 19 | 81 |
| 24 | 18 | 82 |
| 25 | 18 | 82 |
| 26 | 18 | 82 |
| 27 | 17 | 83 |
| 28 | 17 | 83 |
| 29 | 16 | 84 |
| 30 | 15 | 85 |
| 31 | 15 | 85 |
Chance of precipitation in May
Lạng Sơn gets around 221 mm of rain over 21.2 wet days in May. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 68% and peaks near 74% on the wettest days. The odds climb toward the end of the month.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 66 | 67 | 67 | 68 | 68 | 68 | 68 | 68 | 68 | 69 | 69 | 69 | 69 | 69 | 70 | 70 | 70 | 71 | 71 | 72 | 72 | 73 | 73 | 74 |
| Rain chance (%) | |
|---|---|
| 1 | 60 |
| 2 | 61 |
| 3 | 62 |
| 4 | 63 |
| 5 | 64 |
| 6 | 65 |
| 7 | 66 |
| 8 | 66 |
| 9 | 67 |
| 10 | 67 |
| 11 | 68 |
| 12 | 68 |
| 13 | 68 |
| 14 | 68 |
| 15 | 68 |
| 16 | 68 |
| 17 | 69 |
| 18 | 69 |
| 19 | 69 |
| 20 | 69 |
| 21 | 69 |
| 22 | 70 |
| 23 | 70 |
| 24 | 70 |
| 25 | 71 |
| 26 | 71 |
| 27 | 72 |
| 28 | 72 |
| 29 | 73 |
| 30 | 73 |
| 31 | 74 |
Humidity in May
Most of May feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, May lands in the oppressive band about 47% of days. Sticky, muggy-or-worse air turns up on roughly 90% of them.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Comfortable (%) | 5 | 5 | 4 | 4 | 4 | 3 | 3 | 3 | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Humid (%) | 10 | 10 | 10 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 8 | 8 | 8 | 8 | 8 | 8 | 7 | 7 | 6 | 6 | 6 | 5 | 5 | 4 | 4 | 3 | 3 | 2 |
| Muggy (%) | 24 | 23 | 23 | 22 | 21 | 20 | 20 | 19 | 18 | 17 | 17 | 17 | 16 | 16 | 16 | 16 | 16 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 14 | 14 | 13 | 12 | 11 | 11 | 10 |
| Oppressive (%) | 54 | 54 | 54 | 55 | 55 | 55 | 54 | 53 | 53 | 52 | 50 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 44 | 43 | 42 | 42 | 41 | 41 | 41 | 41 | 41 | 40 | 40 | 39 | 39 |
| Miserable (%) | 7 | 8 | 9 | 10 | 11 | 13 | 14 | 16 | 17 | 19 | 20 | 22 | 23 | 25 | 26 | 27 | 29 | 30 | 31 | 33 | 34 | 35 | 36 | 37 | 39 | 40 | 42 | 43 | 45 | 47 | 48 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|---|
| 1 | 0 | 5 | 10 | 24 | 54 | 7 |
| 2 | 0 | 5 | 10 | 23 | 54 | 8 |
| 3 | 0 | 4 | 10 | 23 | 54 | 9 |
| 4 | 0 | 4 | 9 | 22 | 55 | 10 |
| 5 | 0 | 4 | 9 | 21 | 55 | 11 |
| 6 | 0 | 3 | 9 | 20 | 55 | 13 |
| 7 | 0 | 3 | 9 | 20 | 54 | 14 |
| 8 | 0 | 3 | 9 | 19 | 53 | 16 |
| 9 | 0 | 3 | 9 | 18 | 53 | 17 |
| 10 | 0 | 3 | 9 | 17 | 52 | 19 |
| 11 | 1 | 3 | 9 | 17 | 50 | 20 |
| 12 | 1 | 2 | 9 | 17 | 50 | 22 |
| 13 | 1 | 2 | 9 | 16 | 49 | 23 |
| 14 | 1 | 2 | 8 | 16 | 48 | 25 |
| 15 | 1 | 2 | 8 | 16 | 47 | 26 |
| 16 | 1 | 2 | 8 | 16 | 46 | 27 |
| 17 | 1 | 2 | 8 | 16 | 45 | 29 |
| 18 | 1 | 2 | 8 | 15 | 44 | 30 |
| 19 | 1 | 2 | 8 | 15 | 44 | 31 |
| 20 | 1 | 1 | 7 | 15 | 43 | 33 |
| 21 | 0 | 1 | 7 | 15 | 42 | 34 |
| 22 | 0 | 1 | 6 | 15 | 42 | 35 |
| 23 | 0 | 1 | 6 | 15 | 41 | 36 |
| 24 | 0 | 1 | 6 | 15 | 41 | 37 |
| 25 | 0 | 1 | 5 | 14 | 41 | 39 |
| 26 | 0 | 1 | 5 | 14 | 41 | 40 |
| 27 | 0 | 1 | 4 | 13 | 41 | 42 |
| 28 | 0 | 1 | 4 | 12 | 40 | 43 |
| 29 | 0 | 1 | 3 | 11 | 40 | 45 |
| 30 | 0 | 1 | 3 | 11 | 39 | 47 |
| 31 | 0 | 1 | 2 | 10 | 39 | 48 |
Wind in May
Winds average 10 km/h in May.
Across May, daily wind ranges from about 9 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 11 | 11 | 11 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| 1 | 11 | calm |
| 2 | 11 | calm |
| 3 | 11 | calm |
| 4 | 11 | calm |
| 5 | 11 | calm |
| 6 | 11 | calm |
| 7 | 10 | calm |
| 8 | 10 | calm |
| 9 | 10 | calm |
| 10 | 10 | calm |
| 11 | 10 | calm |
| 12 | 10 | calm |
| 13 | 10 | calm |
| 14 | 10 | calm |
| 15 | 10 | calm |
| 16 | 10 | calm |
| 17 | 10 | calm |
| 18 | 10 | calm |
| 19 | 10 | calm |
| 20 | 10 | calm |
| 21 | 10 | calm |
| 22 | 9 | calm |
| 23 | 9 | calm |
| 24 | 9 | calm |
| 25 | 9 | calm |
| 26 | 9 | calm |
| 27 | 9 | calm |
| 28 | 9 | calm |
| 29 | 9 | calm |
| 30 | 9 | calm |
| 31 | 9 | calm |
Sunrise & sunset in May
Daylight runs from about 12 h 48 min at the start of May to 13 h 12 min by month's end. The lit band spans sunrise to sunset each day.
Days grow by about 24 minutes over May. Sunrise moves from 5:26 AM to 5:14 AM, and sunset from 6:14 PM to 6:27 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 12.8 | 12.8 | 12.8 | 12.8 | 12.9 | 12.9 | 12.9 | 12.9 | 12.9 | 12.9 | 13.0 | 13.0 | 13.0 | 13.0 | 13.0 | 13.0 | 13.1 | 13.1 | 13.1 | 13.1 | 13.1 | 13.1 | 13.1 | 13.1 | 13.2 | 13.2 | 13.2 | 13.2 | 13.2 | 13.2 | 13.2 |
| Sunrise (AM) | 5:26 | 5:26 | 5:25 | 5:24 | 5:24 | 5:23 | 5:23 | 5:22 | 5:21 | 5:21 | 5:20 | 5:20 | 5:19 | 5:19 | 5:18 | 5:18 | 5:18 | 5:17 | 5:17 | 5:16 | 5:16 | 5:16 | 5:15 | 5:15 | 5:15 | 5:15 | 5:14 | 5:14 | 5:14 | 5:14 | 5:14 |
| Sunset (PM) | 6:14 | 6:14 | 6:15 | 6:15 | 6:16 | 6:16 | 6:16 | 6:17 | 6:17 | 6:18 | 6:18 | 6:19 | 6:19 | 6:20 | 6:20 | 6:20 | 6:21 | 6:21 | 6:22 | 6:22 | 6:23 | 6:23 | 6:24 | 6:24 | 6:24 | 6:25 | 6:25 | 6:26 | 6:26 | 6:27 | 6:27 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 12.8 | 5:26 | 6:14 |
| 2 | 12.8 | 5:26 | 6:14 |
| 3 | 12.8 | 5:25 | 6:15 |
| 4 | 12.8 | 5:24 | 6:15 |
| 5 | 12.9 | 5:24 | 6:16 |
| 6 | 12.9 | 5:23 | 6:16 |
| 7 | 12.9 | 5:23 | 6:16 |
| 8 | 12.9 | 5:22 | 6:17 |
| 9 | 12.9 | 5:21 | 6:17 |
| 10 | 12.9 | 5:21 | 6:18 |
| 11 | 13.0 | 5:20 | 6:18 |
| 12 | 13.0 | 5:20 | 6:19 |
| 13 | 13.0 | 5:19 | 6:19 |
| 14 | 13.0 | 5:19 | 6:20 |
| 15 | 13.0 | 5:18 | 6:20 |
| 16 | 13.0 | 5:18 | 6:20 |
| 17 | 13.1 | 5:18 | 6:21 |
| 18 | 13.1 | 5:17 | 6:21 |
| 19 | 13.1 | 5:17 | 6:22 |
| 20 | 13.1 | 5:16 | 6:22 |
| 21 | 13.1 | 5:16 | 6:23 |
| 22 | 13.1 | 5:16 | 6:23 |
| 23 | 13.1 | 5:15 | 6:24 |
| 24 | 13.1 | 5:15 | 6:24 |
| 25 | 13.2 | 5:15 | 6:24 |
| 26 | 13.2 | 5:15 | 6:25 |
| 27 | 13.2 | 5:14 | 6:25 |
| 28 | 13.2 | 5:14 | 6:26 |
| 29 | 13.2 | 5:14 | 6:26 |
| 30 | 13.2 | 5:14 | 6:27 |
| 31 | 13.2 | 5:14 | 6:27 |
Solar energy in May
Average shortwave solar energy reaching the ground each day in May, about 4.61 kWh/m².
For context, solar energy here swings from a low near 2.23 kWh/m² to a high of 4.72 kWh/m² in July across the year — May's 4.61 kWh/m² sits near the top of that range.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 4.5 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 | 4.6 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 4.5 | Bright |
| 2 | 4.6 | Bright |
| 3 | 4.6 | Bright |
| 4 | 4.6 | Bright |
| 5 | 4.6 | Bright |
| 6 | 4.6 | Bright |
| 7 | 4.6 | Bright |
| 8 | 4.6 | Bright |
| 9 | 4.6 | Bright |
| 10 | 4.6 | Bright |
| 11 | 4.6 | Bright |
| 12 | 4.6 | Bright |
| 13 | 4.6 | Bright |
| 14 | 4.6 | Bright |
| 15 | 4.6 | Bright |
| 16 | 4.6 | Bright |
| 17 | 4.6 | Bright |
| 18 | 4.6 | Bright |
| 19 | 4.6 | Bright |
| 20 | 4.6 | Bright |
| 21 | 4.6 | Bright |
| 22 | 4.6 | Bright |
| 23 | 4.6 | Bright |
| 24 | 4.6 | Bright |
| 25 | 4.6 | Bright |
| 26 | 4.6 | Bright |
| 27 | 4.6 | Bright |
| 28 | 4.6 | Bright |
| 29 | 4.6 | Bright |
| 30 | 4.6 | Bright |
| 31 | 4.6 | Bright |
Hazard calendar for Lạng Sơn
In May, Lạng Sơn sits inside its monsoon season. The full year is below, with each hazard's peak months called out.
Lạng Sơn's monsoon runs May–September, when most of the year's rain falls.
Is May a good time to visit Lạng Sơn?
Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
May is a reasonable time to visit Lạng Sơn for sightseeing.
What to pack for Lạng Sơn in May
From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In May, Lạng Sơn sees daytime highs around 29°C and nights near 23°C. Pack light clothes and rain gear. Worth having: sun protection. About 21 days see rain.
UV index in Lạng Sơn in May
Clear-sky midday UV in May peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Lạng Sơn peaks around June 23 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 at about 6 (high).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 6 | 7 | 9 | 7 | 9 | 12 | 12 | 10 | 10 | 8 | 6 | 6 |
| Level | High | High | Very high | High | Very high | Extreme | Extreme | Extreme | Very high | Very high | High | High |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 6 | High |
| Feb | 7 | High |
| Mar | 9 | Very high |
| Apr | 7 | High |
| May | 9 | Very high |
| Jun | 12 | Extreme |
| Jul | 12 | Extreme |
| Aug | 10 | Extreme |
| Sep | 10 | Very high |
| Oct | 8 | Very high |
| Nov | 6 | High |
| Dec | 6 | High |
Air quality in Lạng Sơn in May
Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.
Air quality in Lạng Sơn is worst in December — around 58 µg/m³ PM2.5 (unhealthy), about 2.3× the cleanest month (July, 25 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 57 | 55 | 55 | 54 | 37 | 29 | 25 | 29 | 36 | 43 | 50 | 58 |
| Level | Unhealthy | Unhealthy | Poor | Poor | Poor | Moderate | Moderate | Moderate | Poor | Poor | Poor | Unhealthy |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 57 | Unhealthy |
| Feb | 55 | Unhealthy |
| Mar | 55 | Poor |
| Apr | 54 | Poor |
| May | 37 | Poor |
| Jun | 29 | Moderate |
| Jul | 25 | Moderate |
| Aug | 29 | Moderate |
| Sep | 36 | Poor |
| Oct | 43 | Poor |
| Nov | 50 | Poor |
| Dec | 58 | Unhealthy |
Where is Lạng Sơn?
Lạng Sơn sits at 21.9°N, 106.8°E, 265 m above sea level, in Vietnam. The nearest listed city is Thị Trấn Na Dương, 26 km away.
Topography around Lạng Sơn
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Lạng Sơn.
Within 3 km, the terrain around Lạng Sơn has only modest variations in elevation — a maximum elevation change of 171 m around an average of 282 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 978 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,481 m.
The land around Lạng Sơn is covered by trees (46%) and artificial surfaces (32%) within 3 km, trees (80%) within 16 km, and trees (89%) within 80 km.
Vietnam travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B / C / F
- 220 V · 50 Hz
- Prices
- ≈ 29% of US
- price level, 2025
- GDP per capita
- $5,066
- 2025
- Happiness
- 6.4 / 10
- World Happiness, 2025
- Safe drinking water
- 59%
- of population, 2024
- Homicide rate
- 1.5
- per 100k, 2011
- Road deaths
- 30.6
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Moderate
- EF EPI 500
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Lạng Sơn (21.8526°, 106.761°, elevation 265 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).