Iida weather in May

In May, Iida sees average daytime highs of 19°C and overnight lows near 9°C, with 191 mm of rain across 13.7 wet days and about 13.8 hours of daylight. It is the 5th-warmest and 5th-wettest month of the year here.

Highs climb over the month, from about 17°C in the first days to 20°C by the end. The sky is clear or mostly clear about 25% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 24 min at the start of May to 14 h 12 min by month's end. Set against the rest of the year, May is Iida's 10th-clearest and 5th-windiest month. For the whole year in context, see Iida's year-round climate.

Daytime high
19°
5th warmest
Overnight low
8th coldest
Rainfall
191 mm
13.7 wet days
Daylight
13 h 54 min
4:49 AM – 6:41 PM
Cloud cover
67%
10th clearest
Wind
6 km/h
5th windiest
Solar energy
5.47 kWh/m²
Travel score
5.4
out of 10

Iida is city in Nagano Prefecture, Japan.

Density
154/km²
people per km²
Founded
1937

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 17°C in the first days to 20°C by the end.

A typical May day in Iida reaches about 19°C in the afternoon and slips back to 9°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 23°C. Set against its neighbours, May runs about 5°C warmer than April and about 3°C cooler than June.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
1177
2177
3177
4177
5177
6178
7178
8188
9188
10188
11188
12189
13189
14189
15199
16199
17199
18199
191910
201910
211910
221910
231910
242010
252010
262011
272011
282011
292011
302011
312011

How May really feels in Iida

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.

Iida 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 / -7°9911.7119.90.0
Feb / -6°10710.28.110.70.0
Mar / -2°17113.1711.71.1
Apr14° / 17412.91.412.93.6
May19° / 19113.7013.85.4
Jun22° / 14°26318014.45.0
Jul25° / 18°30820.3014.25.0
Aug27° / 19°18418.6013.35.3
Sep23° / 15°22815.5012.25.7
Oct18° / 21012.9011.15.3
Nov11° / 12610.41.210.12.9
Dec / -3°100127.99.60.3

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 25% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 11% of May, with mostly cloudy or overcast conditions the remaining 64%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14258
24159
34159
44159
54060
64060
73961
83862
93763
103664
113664
123664
133664
143664
153565
163664
173664
183664
193565
203565
213565
223565
233466
243466
253367
263367
273268
283268
293169
303070
312971

Chance of precipitation in May

Any precipitation

Iida gets around 191 mm of rain over 13.7 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 44% and peaks near 46% on the wettest days.

0%20%40%60%151015202531
Rain chance (%)
141
241
341
442
542
643
743
844
944
1045
1145
1246
1346
1446
1546
1645
1745
1845
1944
2044
2144
2244
2343
2443
2543
2643
2743
2843
2943
3044
3144

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 92% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
19730
29730
39730
49640
59640
69550
79550
89550
99451
109361
119361
129361
139361
149271
159271
169271
179271
189271
199181
209181
219181
229091
239091
249091
2589101
2689101
2788111
2887121
2987121
3086131
3185141

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
236calm
246calm
256calm
266calm
276calm
285calm
295calm
305calm
315calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 24 min at the start of May to 14 h 12 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 5:03 AM to 4:40 AM, and sunset from 6:28 PM to 6:52 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.45:036:28
213.55:026:29
313.55:016:30
413.55:006:31
513.54:596:32
613.64:586:33
713.64:576:34
813.64:566:34
913.74:556:35
1013.74:546:36
1113.74:536:37
1213.84:526:38
1313.84:516:39
1413.84:516:39
1513.84:506:40
1613.94:496:41
1713.94:486:42
1813.94:476:43
1913.94:476:43
2014.04:466:44
2114.04:456:45
2214.04:456:46
2314.04:446:46
2414.14:436:47
2514.14:436:48
2614.14:426:49
2714.14:426:49
2814.14:416:50
2914.24:416:51
3014.24:406:51
3114.24:406:52

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.47 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.52 kWh/m² to a high of 5.47 kWh/m² in May across the year — May's 5.47 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.4Bright
25.4Bright
35.4Bright
45.4Bright
55.4Bright
65.4Bright
75.4Bright
85.4Bright
95.4Bright
105.4Bright
115.4Bright
125.4Bright
135.4Bright
145.4Bright
155.5Bright
165.5Bright
175.5Bright
185.5Bright
195.5Bright
205.5Bright
215.5Bright
225.6Bright
235.6Bright
245.6Bright
255.6Bright
265.6Bright
275.5Bright
285.5Bright
295.5Bright
305.5Bright
315.5Bright
Planning a trip in May

Is May a good time to visit Iida?

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

5.4
Sightseeing
2nd-best month of the year
2.1
Beach & pool
5th-best month of the year

May is a reasonable time to visit Iida for sightseeing.

What to pack for Iida in May

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

In May, Iida sees daytime highs around 19°C and nights near 9°C. Worth packing: rain gear and sun protection. About 14 days see rain.

rain gearsun protection

UV index in Iida 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 Iida peaks around July 13 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 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 13UV 11Dec 20UV 2
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Extreme
Jul11Extreme
Aug9Very high
Sep10Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Iida 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 Iida is worst in April — around 18 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (December, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1818 µg/m³Dec 168 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar16Moderate
Apr18Moderate
May17Moderate
Jun15Moderate
Jul11Good
Aug11Good
Sep10Good
Oct9Good
Nov8Good
Dec8Good
Location & terrain

Where is Iida?

Iida sits at 35.5°N, 137.8°E, 517 m above sea level, in Japan. The nearest listed city is Komagane, 24 km away.

Topography around Iida

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

Within 3 km, the terrain around Iida has large variations in elevation — a maximum elevation change of 733 m around an average of 565 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 2,037 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,167 m.

The land around Iida is covered by artificial surfaces (53%) and trees (36%) within 3 km, trees (86%) within 16 km, and trees (90%) within 80 km.

3 km
733 m
16 km
2,037 m
80 km
3,167 m
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Komagane 24 km · Nakatsugawa 29 km · Ina 36 km · Ena 40 km · Minamiminowa 42 km · Kinoshita 45 km · Tatsuno 54 km · Mizunami 54 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 Iida (35.5196°, 137.8207°, elevation 517 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).