Irun weather in September

In September, Irun sees average daytime highs of 21°C and overnight lows near 14°C, with 96 mm of rain across 12.7 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 23°C in the first days to 20°C by the end. The sky is clear or mostly clear about 30% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Irun's 2nd-clearest and 9th-windiest month. For the whole year in context, see Irun's year-round climate.

Daytime high
21°
3rd warmest
Overnight low
14°
10th coldest
Rainfall
96 mm
12.7 wet days
Daylight
12 h 18 min
6:53 AM – 7:10 PM
Cloud cover
56%
2nd clearest
Wind
8 km/h
9th windiest
Solar energy
4.17 kWh/m²
Travel score
6.1
out of 10

Irun is capital town of the municipality of Irun, Spain.

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 23°C in the first days to 20°C by the end.

A typical September day in Irun reaches about 21°C in the afternoon and slips back to 14°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 17°C and 27°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12315
22315
32315
42315
52214
62214
72214
82214
92214
102214
112214
122214
132214
142214
152214
162114
172114
182113
192113
202113
212113
222113
232113
242113
252113
262013
272013
282013
292013
302013

Irun weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan10° / 12314.71.29.22.1
Feb11° / 11113.31.910.22.4
Mar14° / 10713.90.911.63.6
Apr15° / 12716.30.113.23.9
May18° / 11°12415.3014.55.1
Jun21° / 14°9812.6015.26.0
Jul23° / 15°8312.3014.96.5
Aug24° / 16°9012.6013.86.7
Sep21° / 14°9612.7012.36.1
Oct18° / 11°12413.8010.85.3
Nov14° / 15315.40.29.53.3
Dec11° / 12614.50.88.82.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 52%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15149
25149
35149
45248
55248
65248
75248
85149
95149
105149
115149
124951
135050
145050
154852
164654
174753
184654
194654
204654
214654
224654
234555
244555
254555
264555
274555
284456
294357
304258

Chance of precipitation in September

Any precipitation

Irun gets around 96 mm of rain over 12.7 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 43% and peaks near 46% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
142
241
341
441
541
641
741
841
941
1042
1142
1242
1343
1443
1544
1644
1745
1845
1945
2045
2145
2245
2345
2445
2545
2645
2745
2846
2946
3046

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the comfortable band about 37% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
118363313
219363312
320363311
421373210
52337329
62437318
72537317
82637307
92737306
102837296
112937295
123037285
133137284
143337274
153437263
163537263
173637252
183837242
193937222
204037211
214138201
224238191
234338181
244438171
254538161
264638160
274738150
284838140
294937130
305137120

Wind in September

Winds average 8 km/h in September.

Across September, daily wind ranges from about 8 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over September. Sunrise moves from 6:36 AM to 7:09 AM, and sunset from 7:38 PM to 6:44 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.06:367:38
213.06:377:36
312.96:387:34
412.96:397:33
512.86:407:31
612.86:417:29
712.76:427:27
812.76:447:25
912.66:457:23
1012.66:467:22
1112.56:477:20
1212.56:487:18
1312.46:497:16
1412.46:507:14
1512.36:527:12
1612.36:537:10
1712.26:547:08
1812.26:557:06
1912.16:567:05
2012.16:577:03
2112.06:587:01
2212.07:006:59
2311.97:016:57
2411.97:026:55
2511.87:036:53
2611.87:046:51
2711.77:056:49
2811.77:076:48
2911.67:086:46
3011.67:096:44

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.17 kWh/m².

For context, solar energy here swings from a low near 1.38 kWh/m² to a high of 5.85 kWh/m² in June across the year — September's 4.17 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.7Bright
44.6Bright
54.6Bright
64.6Bright
74.5Bright
84.5Bright
94.4Bright
104.4Bright
114.3Bright
124.3Bright
134.2Bright
144.2Bright
154.1Bright
164.1Bright
174.0Bright
184.0Bright
194.0Moderate
203.9Moderate
213.9Moderate
223.8Moderate
233.8Moderate
243.7Moderate
253.7Moderate
263.6Moderate
273.6Moderate
283.6Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Is September a good time to visit Irun?

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

6.1
Sightseeing
3rd-best month of the year
4.0
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Irun for sightseeing.

What to pack for Irun in September

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

In September, Irun sees daytime highs around 21°C and nights near 14°C. Worth packing: rain gear. About 13 days see rain.

rain gear

Sea temperature near Irun in September

The nearest coast averages about 21°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 22°C and coldest in February near 12°C.

It's comfortable for a long swim from Jul 1 to Sep 25 — about 2.9 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb12Bracing
Mar13Bracing
Apr14Bracing
May16Cool
Jun19Cool
Jul21Refreshing
Aug22Refreshing
Sep21Refreshing
Oct18Cool
Nov16Cool
Dec14Bracing

UV index in Irun in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Irun peaks around July 15 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 15UV 8Dec 22UV 1
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar5Moderate
Apr6High
May6High
Jun8Very high
Jul8Very high
Aug8Very high
Sep5High
Oct4Moderate
Nov2Low
Dec1Low

Air quality in Irun in September

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Irun is worst in February — around 16 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (November, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodFeb 2116 µg/m³Nov 207 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb16Moderate
Mar15Moderate
Apr12Good
May9Good
Jun9Good
Jul9Good
Aug9Good
Sep9Good
Oct8Good
Nov7Good
Dec8Good
Location & terrain

Where is Irun?

Irun sits at 43.3°N, 1.8°W, 23 m above sea level, in Spain. The nearest listed city is Hondarribia, 3.0 km away.

Topography around Irun

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

Within 3 km, the terrain around Irun has significant variations in elevation — a maximum elevation change of 342 m around an average of 53 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 883 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,044 m.

The land around Irun is covered by trees (47%) and artificial surfaces (26%) within 3 km, trees (45%) and water (36%) within 16 km, and trees (47%) and water (25%) within 80 km.

3 km
342 m
16 km
883 m
80 km
2,044 m
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Hondarribia 3.0 km · Errenteria 10 km · Pasaia 11 km · San Sebastian 15 km · Hernani 17 km · Lasarte 20 km · Oria 21 km · Biarritz 25 km

Spain travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 65% of US
price level, 2025
GDP per capita
$38,627
2025
Happiness
6.5 / 10
World Happiness, 2025
Safe drinking water
99%
of population, 2024
Homicide rate
0.7
per 100k, 2023
Road deaths
3.9
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 540
Religion
Roman Catholic 58%atheist 16%agnostic 11%non-believer 11%

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 Irun (43.339°, -1.7894°, elevation 23 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. 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).