Ōmachi weather in May

In May, Ōmachi sees average daytime highs of 14°C and overnight lows near 6°C, with 237 mm of precipitation across 17.8 wet days and about 13.9 hours of daylight. It is the 5th-warmest and 5th-wettest month of the year here.

Highs climb over the month, from about 12°C in the first days to 17°C by the end. The sky is clear or mostly clear about 22% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 30 min at the start of May to 14 h 18 min by month's end. Set against the rest of the year, May is Ōmachi's 5th-clearest and 6th-windiest month. For the whole year in context, see Ōmachi's year-round climate.

Daytime high
14°
5th warmest
Overnight low
8th coldest
Precipitation
237 mm
17.8 wet days
Daylight
13 h 54 min
4:47 AM – 6:43 PM
Cloud cover
69%
5th clearest
Wind
6 km/h
6th windiest
Solar energy
5.74 kWh/m²
Travel score
3.5
out of 10

Ōmachi is dissolved municipality in Kitaazumi district, Nagano prefecture, Japan.

Founded
1889

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

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 12°C in the first days to 17°C by the end.

A typical May day in Ōmachi reaches about 14°C in the afternoon and slips back to 6°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 10°C and 19°C. Set against its neighbours, May runs about 7°C warmer than April and about 4°C cooler than June.

10°20°151015202531
Avg high (°C)Avg low (°C)
1112
2113
3123
4123
5123
6123
7134
8134
9134
10134
11145
12145
13145
14145
15145
16156
17156
18156
19156
20156
21167
22167
23167
24167
25167
26168
27168
28168
29178
30178
31178

How May really feels in Ōmachi

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.

Ōmachi weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-5° / -11°19322.4249.80.0
Feb-3° / -10°16718.319.610.60.0
Mar / -6°2111919.111.70.0
Apr / -1°20016.69.912.90.9
May14° / 23717.81.313.93.5
Jun18° / 11°34420.6014.44.1
Jul22° / 15°45124.4014.24.3
Aug23° / 16°29721.9013.44.9
Sep19° / 12°29219.1012.24.6
Oct13° / 22716.31.111.13.2
Nov / -2°18317.311.110.10.6
Dec-2° / -8°19621.421.49.60.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 22% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 13% of May, with mostly cloudy or overcast conditions the remaining 65%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14159
24159
34159
44060
54060
63961
73961
83862
93862
103763
113763
123664
133664
143664
153565
163565
173466
183466
193367
203268
213268
223268
233169
243169
253070
263070
273070
282971
292971
302872
312872

Chance of precipitation in May

Any precipitationSnow

Ōmachi gets around 237 mm of rain and snow over 17.8 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 57% and peaks near 60% on the wettest days, and about 1 day brings snow. The odds climb toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)Snow chance (%)
15315
25214
35313
45312
55311
65310
7549
8548
9557
10557
11566
12566
13565
14575
15574
16574
17583
18583
19583
20582
21582
22591
23591
24591
25591
26591
27591
28590
29590
30590
31600

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May 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 (%)
11000
21000
31000
41000
51000
61000
71000
81000
91000
101000
11991
12991
13991
14991
15991
16991
17991
18991
19991
20991
21991
22991
23991
24991
25991
26991
27991
28991
29982
30982
31982

Wind in May

Winds average 6 km/h in May.

Across May, 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
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 30 min at the start of May to 14 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 48 minutes over May. Sunrise moves from 5:02 AM to 4:37 AM, and sunset from 6:30 PM to 6:54 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.55:026:30
213.55:006:31
313.54:596:32
413.64:586:33
513.64:576:33
613.64:566:34
713.74:556:35
813.74:546:36
913.74:536:37
1013.84:526:38
1113.84:516:39
1213.84:506:39
1313.94:496:40
1413.94:486:41
1513.94:486:42
1613.94:476:43
1714.04:466:44
1814.04:456:45
1914.04:446:45
2014.04:446:46
2114.14:436:47
2214.14:426:48
2314.14:426:49
2414.14:416:49
2514.24:406:50
2614.24:406:51
2714.24:396:52
2814.24:396:52
2914.24:386:53
3014.34:386:54
3114.34:376:54

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.74 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.39 kWh/m² to a high of 5.74 kWh/m² in May across the year — May's 5.74 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.8Bright
25.8Bright
35.8Bright
45.8Bright
55.8Bright
65.8Bright
75.8Bright
85.8Bright
95.7Bright
105.7Bright
115.7Bright
125.7Bright
135.7Bright
145.7Bright
155.7Bright
165.7Bright
175.7Bright
185.8Bright
195.8Bright
205.8Bright
215.8Bright
225.8Bright
235.8Bright
245.8Bright
255.8Bright
265.8Bright
275.8Bright
285.8Bright
295.8Bright
305.7Bright
315.7Bright
Planning a trip in May

Hazard calendar for Ōmachi

In seasonPeak

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

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

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

Is May a good time to visit Ōmachi?

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

3.5
Sightseeing
5th-best month of the year
0.2
Beach & pool
5th-best month of the year

May is a weaker month for outdoor sightseeing in Ōmachi.

What to pack for Ōmachi in May

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

In May, Ōmachi sees daytime highs around 14°C and nights near 6°C. Pack rain gear. Worth having: a warm layer and sun protection. About 18 days see rain.

rain geara warm layersun protection

Sea temperature near Ōmachi in May

The nearest coast averages about 15°C in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 61 km away) is warmest in August at about 27°C and coldest in March near 10°C.

It's comfortable for a long swim from Jun 18 to Nov 3 — about 4.6 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb11Bracing
Mar10Bracing
Apr11Bracing
May15Cool
Jun20Cool
Jul24Refreshing
Aug27Warm
Sep25Warm
Oct22Refreshing
Nov19Cool
Dec16Cool

UV index in Ōmachi in May

LowModerateHighVery highExtreme

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 Ōmachi peaks around July 20 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highModerateJul 20UV 10Dec 21UV 2
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Very high
Jul10Extreme
Aug10Extreme
Sep9Very high
Oct6High
Nov3Moderate
Dec2Moderate

Air quality in Ōmachi 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 Ōmachi is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1721 µg/m³Dec 1510 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar20Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug13Moderate
Sep12Good
Oct11Good
Nov11Good
Dec10Good
Location & terrain

Where is Ōmachi?

Ōmachi sits at 36.5°N, 137.9°E, 714 m above sea level, in Japan. The nearest listed city is Hotaka, 18 km away.

Topography around Ōmachi

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

Within 3 km, the terrain around Ōmachi has significant variations in elevation — a maximum elevation change of 486 m around an average of 823 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 2,371 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,120 m.

The land around Ōmachi is covered by trees (50%) and artificial surfaces (26%) within 3 km, trees (83%) within 16 km, and trees (75%) within 80 km.

3 km
486 m
16 km
2,371 m
80 km
3,120 m
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Hotaka 18 km · Chikuma 20 km · Toyoshina 22 km · Azumino 24 km · Sakaki 29 km · Matsumoto 31 km · Nagano 33 km · Ueda 39 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 Ōmachi (36.5°, 137.8667°, elevation 714 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).