Vieng Xai weather in May

In May, Vieng Xai sees average daytime highs of 29°C and overnight lows near 20°C, with 205 mm of rain across 23.2 wet days and about 13 hours of daylight. It is the 2nd-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 10% of the time in May, and the air most often feels muggy.

Daylight stretches from about 12 h 42 min at the start of May to 13 h 06 min by month's end. Set against the rest of the year, May is Vieng Xai's 9th-clearest and 7th-windiest month. For the whole year in context, see Vieng Xai's year-round climate.

Daytime high
29°
2nd warmest
Overnight low
20°
9th coldest
Rainfall
205 mm
23.2 wet days
Daylight
13 hours
5:30 AM – 6:28 PM
Cloud cover
78%
9th clearest
Wind
5 km/h
7th windiest
Solar energy
5.13 kWh/m²
Travel score
3.7
out of 10

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 29°C through the month.

A typical May day in Vieng Xai reaches about 29°C in the afternoon and slips back to 20°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 32°C. Set against its neighbours, May runs about 1°C warmer than April and on par with June.

15°20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12819
22819
32919
42919
52919
62920
72920
82920
92920
102920
112920
122920
132920
142920
152920
162920
172920
182920
192920
202920
212921
222921
232921
242921
252921
262921
272921
282921
292921
302921
312921

How May really feels in Vieng Xai

Once humidity and wind are folded in, May averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Vieng Xai weather by month

How May compares with the rest of the year at a glance. May is the 2nd-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan20° / 11°224.410.97.0
Feb22° / 12°143.811.37.6
Mar25° / 15°6010.611.96.8
Apr28° / 18°10917.712.55.1
May29° / 20°20523.2133.7
Jun29° / 22°20124.213.23.2
Jul29° / 22°26426.213.13.3
Aug28° / 21°30226.812.73.6
Sep27° / 20°19320.112.14.7
Oct25° / 18°9114.211.56.1
Nov23° / 15°326.3117.3
Dec20° / 11°194.210.87.1

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

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%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13961
23862
33862
43763
53664
63565
73367
83268
93169
103070
112971
122773
132674
142476
152278
162278
172080
181882
191882
201684
211486
221387
231288
241189
251189
26991
27991
28991
29991
30991
31991

Chance of precipitation in May

Any precipitation

Vieng Xai gets around 205 mm of rain over 23.2 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 75% and peaks near 82% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
170
270
370
470
570
670
770
870
971
1071
1172
1273
1374
1474
1575
1675
1776
1876
1977
2077
2178
2278
2379
2480
2580
2681
2781
2882
2982
3082
3182

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

Most of May feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, May lands in the muggy band about 59% of days. Sticky, muggy-or-worse air turns up on roughly 89% of them.

0%25%50%75%100%151015202531
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1413767
2413767
3412768
4412759
54117411
64117312
74107313
84107115
9497017
10496918
11486820
12486721
13486523
14476425
15476227
16476029
17475831
18375733
19375535
20375337
21375139
22375041
23374843
24264645
25264447
26264350
27264151
28154054
29153955
30143857
31143758

Wind in May

Winds average 5 km/h in May.

Across May, daily wind ranges from about 5 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 12 h 42 min at the start of May to 13 h 06 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 5:38 AM to 5:26 AM, and sunset from 6:22 PM to 6:35 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:386:22
212.85:386:23
312.85:376:23
412.85:366:24
512.85:366:24
612.85:356:24
712.85:356:25
812.85:346:25
912.95:346:25
1012.95:336:26
1112.95:336:26
1212.95:326:27
1312.95:326:27
1412.95:316:27
1513.05:316:28
1613.05:306:28
1713.05:306:29
1813.05:306:29
1913.05:296:30
2013.05:296:30
2113.05:296:30
2213.05:286:31
2313.15:286:31
2413.15:286:32
2513.15:286:32
2613.15:276:33
2713.15:276:33
2813.15:276:33
2913.15:276:34
3013.15:276:34
3113.15:266:35

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.13 kWh/m².

For context, solar energy here swings from a low near 3.16 kWh/m² to a high of 5.2 kWh/m² in April across the year — May's 5.13 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.3Bright
45.3Bright
55.3Bright
65.3Bright
75.3Bright
85.3Bright
95.3Bright
105.3Bright
115.2Bright
125.2Bright
135.2Bright
145.2Bright
155.2Bright
165.1Bright
175.1Bright
185.1Bright
195.1Bright
205.0Bright
215.0Bright
225.0Bright
235.0Bright
245.0Bright
255.0Bright
265.0Bright
274.9Bright
284.9Bright
294.9Bright
304.9Bright
314.9Bright
Planning a trip in May

Hazard calendar for Vieng Xai

In seasonPeak

In May, Vieng Xai sits inside its monsoon season. The full year is below, with each hazard's peak months called out.

Vieng Xai's monsoon runs May–September, when most of the year's rain falls.

Monsoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is May a good time to visit Vieng Xai?

Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

3.7
Sightseeing
9th-best month of the year
4.7
Beach & pool
7th-best month of the year

May is a weaker month for outdoor sightseeing in Vieng Xai.

What to pack for Vieng Xai in May

From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In May, Vieng Xai sees daytime highs around 29°C and nights near 20°C. Pack light clothes and rain gear. Worth having: sun protection. About 23 days see rain.

light clothesrain gearsun protection

UV index in Vieng Xai in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Vieng Xai peaks around August 12 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 7 (high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highHighAug 12UV 14Dec 17UV 7
UV index (midday)Level
Jan8Very high
Feb9Very high
Mar10Very high
Apr9Very high
May10Extreme
Jun14Extreme
Jul13Extreme
Aug14Extreme
Sep10Very high
Oct9Very high
Nov8Very high
Dec7High

Air quality in Vieng Xai in May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.

Air quality in Vieng Xai is worst in April — around 288 µg/m³ PM2.5 (very unhealthy), about 35.5× the cleanest month (August, 8 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0306090120150180210240270JanFebMarAprMayJunJulAugSepOctNovDecModerateUnhealthyVery unhealthyUnhealthyGoodModerateApr 15263 µg/m³Aug 128 µg/m³
PM2.5 (µg/m³)Level
Jan20Moderate
Feb28Moderate
Mar98Unhealthy
Apr288Very unhealthy
May64Unhealthy
Jun14Moderate
Jul9Good
Aug8Good
Sep11Good
Oct15Moderate
Nov15Moderate
Dec19Moderate
Location & terrain

Where is Vieng Xai?

Vieng Xai sits at 20.4°N, 104.2°E, 0 m above sea level, in Laos. The nearest listed city is Xam Nua, 19 km away.

Bản Na HỷSơn LaHòa BìnhÍt OngThị Trấn Thuận ChâuThị Trấn Lam SơnNghĩa Lộ

Topography around Vieng Xai

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Vieng Xai.

Within 3 km, the terrain around Vieng Xai has large variations in elevation — a maximum elevation change of 661 m around an average of 915 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,259 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,998 m.

The land around Vieng Xai is covered by trees (65%) and grassland (25%) within 3 km, trees (86%) within 16 km, and trees (82%) within 80 km.

3 km
661 m
16 km
1,259 m
80 km
1,998 m
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Xam Nua 19 km · Bản Na Hỷ 99 km · Sơn La 107 km · Hòa Bình 125 km · Ít Ong 125 km · Thị Trấn Thuận Châu 127 km · Thị Trấn Lam Sơn 135 km · Nghĩa Lộ 136 km

Laos travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B / C / E / F
230 V · 50 Hz
Prices
≈ 23% of US
price level, 2025
GDP per capita
$2,325
2025
Happiness
5.5 / 10
World Happiness, 2025
Safe drinking water
35%
of population, 2024
Road deaths
17.9
per 100k/yr, 2019
Income group
Lower middle
World Bank
English
Low
EF EPI 461
Religion
Buddhist 65%none 31%other/not stated 2%Christian 2%

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 Vieng Xai (20.4068°, 104.2238°, elevation 0 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).