Saikai weather in January

In January, Saikai sees average daytime highs of 10°C and overnight lows near 7°C, with 70 mm of precipitation across 9.6 wet days and about 10.1 hours of daylight. It is the 12th-warmest and 12th-wettest month of the year here.

Day-to-day highs hold fairly steady near 10°C through the month. The sky is clear or mostly clear about 17% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 h 54 min at the start of January to 10 h 24 min by month's end. Set against the rest of the year, January is Saikai's 11th-clearest and 1st-windiest month. For the whole year in context, see Saikai's year-round climate.

Daytime high
10°
12th warmest
Overnight low
1st coldest
Precipitation
70 mm
9.6 wet days
Daylight
10 hours
7:29 AM – 5:32 PM
Cloud cover
69%
11th clearest
Wind
17 km/h
1st windiest
Solar energy
2.27 kWh/m²
Travel score
2.1
out of 10

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 10°C through the month.

A typical January day in Saikai reaches about 10°C in the afternoon and slips back to 7°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 6°C and 13°C. Set against its neighbours, January runs about 3°C cooler than December and on par with February.

10°15°151015202531
Avg high (°C)Avg low (°C)
1117
2107
3107
4107
5107
6107
7107
8107
9107
10107
11107
12107
13107
14107
15106
16106
1796
1896
1996
2096
2196
2296
2396
2496
2596
2696
2796
2896
2996
3096
3196

How January really feels in Saikai

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.

Saikai weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan10° / 709.60.510.12.1
Feb10° / 8590.410.82.4
Mar13° / 13411.1011.73.6
Apr17° / 13°15810.7012.85.3
May21° / 17°17710.4013.76.3
Jun24° / 21°37215.8014.15.7
Jul27° / 25°30616.20145.3
Aug29° / 26°18214.1013.25.2
Sep26° / 23°18811.3012.26.5
Oct22° / 19°1096.7011.27.4
Nov17° / 14°988010.35.8
Dec12° / 819.209.93.3

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 17% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 16% of January, with mostly cloudy or overcast conditions the remaining 67%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13961
23961
33961
43862
53763
63565
73565
83466
93367
103367
113268
123268
133169
143070
153070
162971
172971
183070
193070
203070
213169
223169
233169
243268
253268
263268
273268
283367
293367
303466
313466

Chance of precipitation in January

Any precipitationSnow

Saikai gets around 70 mm of rain and snow over 9.6 wet days in January, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 31% and peaks near 35% on the wettest days, and about 1 day brings snow. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)Snow chance (%)
1270
2270
3270
4271
5271
6271
7271
8271
9281
10281
11291
12301
13301
14312
15322
16332
17332
18342
19342
20353
21353
22353
23353
24353
25353
26343
27343
28343
29333
30333
31323

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 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1991
2991
3991
4991
5991
6991
7991
8991
9991
10991
11991
12991
13991
14991
15991
16991
17991
18991
19991
20991
21991
22991
23991
241000
251000
261000
271000
281000
29991
30991
31991

Wind in January

Winds average 17 km/h in January, the windiest month of the year.

Across January, daily wind ranges from about 17 km/h on the calmest days to 17 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
117light breeze
217light breeze
317light breeze
417light breeze
517light breeze
617light breeze
717light breeze
817light breeze
917light breeze
1017light breeze
1117light breeze
1217light breeze
1317light breeze
1417light breeze
1517light breeze
1617light breeze
1717light breeze
1817light breeze
1917light breeze
2017light breeze
2117light breeze
2217light breeze
2317light breeze
2417light breeze
2517light breeze
2617light breeze
2717light breeze
2817light breeze
2917light breeze
3017light breeze
3117light breeze

Sunrise & sunset in January

DaylightNight

Daylight runs from about 9 h 54 min at the start of January to 10 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 30 minutes over January. Sunrise moves from 7:29 AM to 7:24 AM, and sunset from 5:20 PM to 5:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.97:295:20
29.97:295:21
39.97:295:22
49.97:295:22
59.97:295:23
69.97:305:24
79.97:305:25
89.97:305:25
99.97:305:26
1010.07:305:27
1110.07:305:28
1210.07:305:29
1310.07:305:29
1410.07:295:30
1510.07:295:31
1610.07:295:32
1710.17:295:33
1810.17:295:34
1910.17:295:35
2010.17:285:35
2110.17:285:36
2210.27:285:37
2310.27:275:38
2410.27:275:39
2510.27:275:40
2610.27:265:41
2710.37:265:42
2810.37:255:43
2910.37:255:44
3010.37:245:45
3110.47:245:46

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.27 kWh/m².

For context, solar energy here swings from a low near 2.14 kWh/m² to a high of 5.41 kWh/m² in May across the year — January's 2.27 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.2Moderate
22.2Moderate
32.2Moderate
42.2Moderate
52.2Moderate
62.2Moderate
72.2Moderate
82.2Moderate
92.2Moderate
102.2Moderate
112.2Moderate
122.2Moderate
132.2Moderate
142.2Moderate
152.2Moderate
162.2Moderate
172.2Moderate
182.2Moderate
192.3Moderate
202.3Moderate
212.3Moderate
222.3Moderate
232.4Moderate
242.4Moderate
252.4Moderate
262.5Moderate
272.5Moderate
282.5Moderate
292.5Moderate
302.6Moderate
312.6Moderate
Planning a trip in January

Hazard calendar for Saikai

In seasonPeak

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

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

Saikai's rainy season runs May–September, when most of the year's rain falls.

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

Is January a good time to visit Saikai?

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

2.1
Sightseeing
12th-best month of the year
0.0
Beach & pool
11th-best month of the year

January is a weaker month for outdoor sightseeing in Saikai.

What to pack for Saikai in January

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

In January, Saikai sees daytime highs around 10°C and nights near 7°C. Pack a warm layer. Worth having: rain gear. About 10 days see rain.

a warm layerrain gear

Sea temperature near Saikai in January

The nearest coast averages about 16°C in January — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 13 km away) is warmest in August at about 27°C and coldest in February near 15°C.

It's comfortable for a long swim from May 27 to Nov 29 — about 6.1 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Cool
Mar16Cool
Apr17Cool
May19Cool
Jun22Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct24Refreshing
Nov21Refreshing
Dec19Cool

UV index in Saikai in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 3 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Saikai peaks around July 15 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highVery highModerateJul 15UV 10Dec 21UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr7Very high
May8Very high
Jun9Very high
Jul10Extreme
Aug8Very high
Sep9Very high
Oct7High
Nov4Moderate
Dec3Moderate

Air quality in Saikai 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 Saikai is worst in April — around 24 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (October, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateModerateGoodModerateApr 1324 µg/m³Oct 1212 µg/m³
PM2.5 (µg/m³)Level
Jan16Moderate
Feb19Moderate
Mar23Moderate
Apr24Moderate
May21Moderate
Jun17Moderate
Jul12Good
Aug12Moderate
Sep12Good
Oct11Good
Nov14Moderate
Dec13Moderate
Location & terrain

Where is Saikai?

Saikai sits at 33.0°N, 129.7°E, 184 m above sea level, in Japan. The nearest listed city is Sasebo, 21 km away.

Topography around Saikai

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

Within 3 km, the terrain around Saikai has significant variations in elevation — a maximum elevation change of 353 m around an average of 182 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 564 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,455 m.

The land around Saikai is covered by trees (96%) within 3 km, water (55%) and trees (42%) within 16 km, and water (68%) and trees (24%) within 80 km.

3 km
353 m
16 km
564 m
80 km
1,455 m
treesgrasslandcroplandartificial surfaceswater
January weather nearby: Sasebo 21 km · Togitsu 23 km · Ōmura 26 km · Obita 27 km · Arita 30 km · Nagasaki 32 km · Ureshinomachi-shimojuku 33 km · Imarichō-kō 37 km

Japan travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B
100 V · 50 / 60 Hz
Prices
≈ 65% of US
price level, 2025
GDP per capita
$35,951
2025
Happiness
6.1 / 10
World Happiness, 2025
Safe drinking water
99%
of population, 2024
Homicide rate
0.2
per 100k, 2023
Road deaths
3.6
per 100k/yr, 2019
Income group
High
World Bank
English
Very low
EF EPI 446
Religion
Shintoism 49%Buddhism 46%other 4%Christianity 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 Saikai (32.9839°, 129.6809°, elevation 184 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). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).