İznik weather in September

In September, İznik sees average daytime highs of 26°C and overnight lows near 15°C, with 40 mm of rain across 6.8 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 28°C in the first days to 24°C by the end. The sky is clear or mostly clear about 59% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is İznik's 3rd-clearest and 7th-windiest month. For the whole year in context, see İznik's year-round climate.

Daytime high
26°
4th warmest
Overnight low
15°
9th coldest
Rainfall
40 mm
6.8 wet days
Daylight
12 h 18 min
5:48 AM – 6:03 PM
Cloud cover
35%
3rd clearest
Wind
7 km/h
7th windiest
Solar energy
4.57 kWh/m²
Travel score
7.7
out of 10

İznik is district and town in the Province of Bursa, Turkey.

Density
30/km²
people per km²

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 28°C in the first days to 24°C by the end.

A typical September day in İznik reaches about 26°C in the afternoon and slips back to 15°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 31°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
12817
22817
32816
42716
52716
62716
72716
82716
92716
102715
112615
122615
132615
142615
152615
162615
172615
182515
192515
202514
212514
222514
232514
242514
252414
262414
272414
282413
292413
302413

How September really feels in İznik

Once humidity and wind are folded in, September 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

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

İznik weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 7411.75.99.41.1
Feb / 6311.15.110.41.8
Mar12° / 7512.43.211.73.2
Apr17° / 6010.50.5135.5
May22° / 11°569.2014.27.0
Jun26° / 15°579.4014.87.1
Jul29° / 18°284.9014.66.6
Aug29° / 18°254.2013.66.5
Sep26° / 15°406.8012.37.7
Oct21° / 11°578.6010.96.7
Nov15° / 578.61.19.84.5
Dec / 7811.949.21.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 59% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 22%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18713
28614
38614
48515
58416
68416
78416
88317
98317
108317
118218
128119
138119
148020
157921
167921
177822
187723
197624
207525
217426
227327
237228
247129
257129
266931
276931
286832
296832
306832

Chance of precipitation in September

Any precipitation

İznik gets around 40 mm of rain over 6.8 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 22% and peaks near 27% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
119
219
319
419
519
619
719
819
919
1019
1119
1219
1319
1420
1520
1620
1721
1822
1922
2023
2124
2224
2325
2426
2526
2627
2727
2827
2926
3026

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 39% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
11735399
21935388
32036377
42236356
52437346
62537325
72738315
82838294
92939284
103040274
113140263
123241253
133341243
143341233
153442222
163442222
173542212
183642202
193742192
203942182
214041171
224241161
234340151
244540141
254739131
264939120
275138110
285238100
295337100
30553690

Wind in September

Winds average 7 km/h in September.

Across September, daily wind ranges from about 6 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 min 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 78 minutes over September. Sunrise moves from 5:33 AM to 6:02 AM, and sunset from 6:29 PM to 5:39 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:336:29
212.95:346:27
312.95:356:26
412.85:366:24
512.85:376:22
612.75:386:21
712.75:396:19
812.65:406:17
912.65:416:15
1012.55:426:14
1112.55:436:12
1212.45:446:10
1312.45:456:09
1412.45:466:07
1512.35:476:05
1612.35:486:03
1712.25:496:02
1812.25:506:00
1912.15:515:58
2012.15:525:56
2112.05:535:55
2212.05:545:53
2311.95:555:51
2411.95:565:49
2511.95:575:48
2611.85:585:46
2711.85:595:44
2811.76:005:43
2911.76:015:41
3011.66:025:39

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.57 kWh/m².

For context, solar energy here swings from a low near 1.55 kWh/m² to a high of 6.77 kWh/m² in July across the year — September's 4.57 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.2Bright
45.2Bright
55.1Bright
65.1Bright
75.0Bright
85.0Bright
94.9Bright
104.9Bright
114.8Bright
124.8Bright
134.7Bright
144.7Bright
154.6Bright
164.6Bright
174.5Bright
184.5Bright
194.4Bright
204.3Bright
214.3Bright
224.2Bright
234.2Bright
244.1Bright
254.1Bright
264.0Bright
274.0Moderate
283.9Moderate
293.9Moderate
303.8Moderate
Planning a trip in September

Is September a good time to visit İznik?

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

7.7
Sightseeing
1st-best month of the year
7.2
Beach & pool
3rd-best month of the year

September is one of the better times to visit İznik for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for İznik in September

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

In September, İznik sees daytime highs around 26°C and nights near 15°C. Worth packing: light clothes and sun protection. About 7 days see rain.

light clothessun protection

Sea temperature near İznik in September

The nearest coast averages about 22°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 55 km away) is warmest in August at about 24°C and coldest in February near 8°C.

It's comfortable for a long swim from Jun 12 to Oct 6 — about 3.8 months when the water holds above 20°C.

5°10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan9Bracing
Feb8Bracing
Mar9Bracing
Apr11Bracing
May16Cool
Jun21Refreshing
Jul23Refreshing
Aug24Warm
Sep22Refreshing
Oct19Cool
Nov15Cool
Dec12Bracing

UV index in İznik in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in İznik peaks around August 10 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateVery highModerateLowAug 10UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr7Very high
May7Very high
Jun9Very high
Jul9Very high
Aug9Very high
Sep7High
Oct4Moderate
Nov2Moderate
Dec2Low

Air quality in İznik 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 İznik is worst in March — around 16 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (December, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodMar 2316 µg/m³Dec 198 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar16Moderate
Apr16Moderate
May15Moderate
Jun13Moderate
Jul10Good
Aug10Good
Sep10Good
Oct10Good
Nov10Good
Dec8Good
Location & terrain

Where is İznik?

İznik sits at 40.4°N, 29.7°E, 99 m above sea level, in Turkey. The nearest listed city is Yenişehir, 19 km away.

Topography around İznik

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

Within 3 km, the terrain around İznik has significant variations in elevation — a maximum elevation change of 319 m around an average of 114 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,174 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,527 m.

The land around İznik is covered by trees (40%) and water (28%) within 3 km, trees (54%) within 16 km, and trees (57%) within 80 km.

3 km
319 m
16 km
1,174 m
80 km
2,527 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Yenişehir 19 km · Osmaneli 26 km · Karamürsel 31 km · Gölcük 33 km · Orhangazi 36 km · Derince 37 km · Körfez 38 km · Bilecik 39 km

Turkey travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 41% of US
price level, 2025
GDP per capita
$18,599
2025
Happiness
5.3 / 10
World Happiness, 2025
Homicide rate
3.2
per 100k, 2023
Road deaths
6.7
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 488
Religion
Muslim 100%other 0%

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 İznik (40.4286°, 29.7211°, elevation 99 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).