Sơn Tây weather in January

In January, Sơn Tây sees average daytime highs of 20°C and overnight lows near 15°C, with 37 mm of rain across 8.3 wet days and about 10.9 hours of daylight. It is the 12th-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 20°C through the month. The sky is clear or mostly clear about 13% of the time in January, and the air most often feels dry.

Daylight stretches from about 10 h 42 min at the start of January to 11 hours by month's end. Set against the rest of the year, January is Sơn Tây's 7th-clearest and 8th-windiest month. For the whole year in context, see Sơn Tây's year-round climate.

Daytime high
20°
12th warmest
Overnight low
15°
1st coldest
Rainfall
37 mm
8.3 wet days
Daylight
10 h 48 min
6:42 AM – 5:33 PM
Cloud cover
76%
7th clearest
Wind
5 km/h
8th windiest
Solar energy
2.1 kWh/m²
Travel score
6.2
out of 10

Sơn Tây is district-level town of Vietnam.

Density
2,032/km²
people per km²
Founded
2009

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 20°C through the month.

A typical January day in Sơn Tây reaches about 20°C in the afternoon and slips back to 15°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 26°C. Set against its neighbours, January runs about 2°C cooler than December and about 2°C cooler than February.

10°15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12115
22115
32115
42115
52115
62115
72015
82015
92015
102015
112015
122015
132015
142015
152015
162015
172015
182015
192015
202015
212015
222015
232015
242015
252015
262015
272015
282015
292015
302015
312015

How January really feels in Sơn Tây

Once humidity and wind are folded in, January 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

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

Sơn Tây weather by month

How January compares with the rest of the year at a glance. January is the 12th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan20° / 15°378.310.96.2
Feb22° / 16°267.911.36.5
Mar25° / 19°4810.411.96.4
Apr29° / 22°8110.712.55.2
May32° / 25°20117.4133.2
Jun33° / 27°21518.213.32.4
Jul33° / 27°25120.513.22.4
Aug33° / 26°31122.112.72.5
Sep32° / 25°20117.912.13.3
Oct29° / 23°10010.511.55.4
Nov26° / 19°486.7117.2
Dec22° / 16°296.510.77.1

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 13% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 10% of January, with mostly cloudy or overcast conditions the remaining 77%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13268
23070
32971
42773
52674
62674
72575
82575
92575
102377
112377
122377
132278
142278
152278
162278
172377
182278
192278
202278
212278
222278
232278
242179
252179
262179
272179
282179
292179
302179
312278

Chance of precipitation in January

Any precipitation

Sơn Tây gets around 37 mm of rain over 8.3 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 26% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
126
227
327
428
528
628
728
829
929
1028
1128
1228
1328
1427
1527
1627
1727
1827
1926
2026
2126
2225
2325
2425
2525
2625
2725
2824
2924
3024
3124

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the dry band about 45% of days. Sticky, muggy-or-worse air turns up on roughly 14% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1402028120
2402027130
3412026130
4412026140
5412025140
6422024150
7422023150
8422022150
9432121150
10432120150
11432220150
12432319150
13442318150
14442418140
15442418140
16442418130
17452418130
18452418130
19462418120
20462318120
21472318120
22472219121
23472119121
24482119121
25482019121
26491919121
27491819121
28491819131
29491719131
30491720132
31481720132

Wind in January

Winds average 5 km/h in January.

Across January, daily wind ranges from about 5 km/h on the calmest days to 6 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
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 10 h 42 min at the start of January to 11 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 18 minutes over January. Sunrise moves from 6:39 AM to 6:40 AM, and sunset from 5:23 PM to 5:42 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
110.76:395:23
210.76:395:24
310.76:405:24
410.76:405:25
510.86:405:26
610.86:415:26
710.86:415:27
810.86:415:27
910.86:415:28
1010.86:415:29
1110.86:415:29
1210.86:425:30
1310.86:425:31
1410.86:425:31
1510.86:425:32
1610.86:425:33
1710.96:425:33
1810.96:425:34
1910.96:425:35
2010.96:425:35
2110.96:425:36
2210.96:425:36
2310.96:425:37
2410.96:425:38
2510.96:425:38
2611.06:415:39
2711.06:415:40
2811.06:415:40
2911.06:415:41
3011.06:415:42
3111.06:405:42

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.1 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.1 kWh/m² to a high of 4.78 kWh/m² in June across the year — January's 2.1 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.3Moderate
22.3Moderate
32.3Moderate
42.2Moderate
52.2Moderate
62.2Moderate
72.1Moderate
82.1Moderate
92.1Moderate
102.1Moderate
112.1Moderate
122.1Moderate
132.1Moderate
142.1Moderate
152.1Moderate
162.1Moderate
172.1Moderate
182.1Moderate
192.1Moderate
202.1Moderate
212.1Moderate
222.1Moderate
232.1Moderate
242.1Moderate
252.1Moderate
262.1Moderate
272.2Moderate
282.2Moderate
292.2Moderate
302.2Moderate
312.3Moderate
Planning a trip in January

Hazard calendar for Sơn Tây

In seasonPeak

In January, Sơn Tây sits inside its pacific typhoon season. The full year is below, with each hazard's peak months called out.

Sơn Tây sits in the Pacific typhoon belt; the season peaks July–October.

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

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

Is January a good time to visit Sơn Tây?

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

6.2
Sightseeing
5th-best month of the year
3.4
Beach & pool
12th-best month of the year

January is a reasonable time to visit Sơn Tây for sightseeing.

What to pack for Sơn Tây in January

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

In January, Sơn Tây sees daytime highs around 20°C and nights near 15°C. Worth packing: rain gear. About 8 days see rain.

rain gear

UV index in Sơn Tây in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sơn Tây peaks around June 20 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 21 at about 6 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecHighVery highHighVery highExtremeVery highVery highHighJun 20UV 11Nov 21UV 6
UV index (midday)Level
Jan6High
Feb7High
Mar9Very high
Apr6High
May7Very high
Jun11Extreme
Jul10Extreme
Aug9Very high
Sep7High
Oct8Very high
Nov6High
Dec6High

Air quality in Sơn Tây in January

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Sơn Tây is worst in December — around 171 µg/m³ PM2.5 (very unhealthy), about 3.4× the cleanest month (July, 50 µg/m³).

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

0306090120150180JanFebMarAprMayJunJulAugSepOctNovDecVery unhealthyUnhealthyPoorUnhealthyVery unhealthyDec 19170 µg/m³Jul 1452 µg/m³
PM2.5 (µg/m³)Level
Jan161Very unhealthy
Feb136Unhealthy
Mar122Unhealthy
Apr106Unhealthy
May76Unhealthy
Jun59Unhealthy
Jul50Poor
Aug68Unhealthy
Sep96Unhealthy
Oct125Unhealthy
Nov152Very unhealthy
Dec171Very unhealthy
Location & terrain

Where is Sơn Tây?

Sơn Tây sits at 21.1°N, 105.5°E, 16 m above sea level, in Vietnam. The nearest listed city is Ba Vì, 14 km away.

Topography around Sơn Tây

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

Within 3 km, the terrain around Sơn Tây has only modest variations in elevation — a maximum elevation change of 32 m around an average of 13 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 694 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,677 m.

The land around Sơn Tây is covered by trees (42%), artificial surfaces (22%) and cropland (21%) within 3 km, trees (44%) and cropland (33%) within 16 km, and trees (66%) and cropland (22%) within 80 km.

3 km
32 m
16 km
694 m
80 km
1,677 m
treesgrasslandcroplandartificial surfacesbare terrainwater
January weather nearby: Ba Vì 14 km · Đan Phượng 17 km · Vĩnh Yên 21 km · Cổ Đô 21 km · Việt Trì 23 km · Phúc Yên 23 km · Thượng Cát 24 km · Bắc Từ Liêm 26 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
none 86%Catholic 6%Buddhist 6%Protestant 1%

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 Sơn Tây (21.1405°, 105.5069°, elevation 16 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).