Lappeenranta weather in September

In September, Lappeenranta sees average daytime highs of 14°C and overnight lows near 8°C, with 56 mm of rain across 10.7 wet days and about 12.6 hours of daylight. It is the 4th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 17°C in the first days to 12°C by the end. The sky is clear or mostly clear about 15% of the time in September, and the air most often feels dry.

Daylight stretches from about 14 hours at the start of September to 11 h 12 min by month's end. Set against the rest of the year, September is Lappeenranta's 7th-clearest and 7th-windiest month. For the whole year in context, see Lappeenranta's year-round climate.

Daytime high
14°
4th warmest
Overnight low
9th coldest
Rainfall
56 mm
10.7 wet days
Daylight
12 h 36 min
5:45 AM – 6:18 PM
Cloud cover
71%
7th clearest
Wind
12 km/h
7th windiest
Solar energy
2.37 kWh/m²
Travel score
4.0
out of 10

Lappeenranta is urban settlement in South Karelia, Finland.

Air quality
Excellent
PM2.5 4.9 µg/m³ · 2019
Density
1,335/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 17°C in the first days to 12°C by the end.

A typical September day in Lappeenranta reaches about 14°C in the afternoon and slips back to 8°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 10°C and 18°C. Set against its neighbours, September runs about 6°C cooler than August and about 7°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11710
21710
31710
41710
51710
61610
7169
8169
9169
10169
11159
12159
13158
14158
15148
16148
17148
18147
19147
20137
21137
22137
23137
24137
25126
26126
27126
28126
29126
30116

How September really feels in Lappeenranta

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.

Lappeenranta weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-4° / -8°4210.311.66.10.0
Feb-4° / -9°3899.48.50.0
Mar / -6°3698.311.30.0
Apr / -1°338.43.314.21.0
May14° / 469.20.3174.3
Jun19° / 11°6611.9018.75.7
Jul22° / 14°73120186.2
Aug20° / 12°7512.4015.55.8
Sep14° / 5610.7012.64.0
Oct / 5711.21.69.71.0
Nov / -2°5411.26.16.90.0
Dec-2° / -6°5211.310.25.30.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 15% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 69%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12971
23070
33070
43169
53169
63169
73268
83268
93268
103268
113268
123268
133268
143367
153268
163268
173268
183268
193169
203169
213070
223070
233070
242971
252971
262971
272971
282971
292872
302872

Chance of precipitation in September

Any precipitation

Lappeenranta gets around 56 mm of rain over 10.7 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 36% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
136
236
336
436
536
636
736
836
937
1037
1137
1237
1337
1437
1537
1637
1736
1836
1936
2035
2135
2235
2335
2435
2534
2634
2734
2834
2934
3035

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September 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%151015202530
Dry (%)Comfortable (%)Humid (%)
177221
279201
380191
482171
583161
684151
786131
887121
989110
1090100
119190
129280
139370
149460
159460
169550
179640
189640
199730
209730
219820
229820
239820
249910
259910
269910
279910
2810000
2910000
3010000

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 12 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
112calm
212calm
312calm
412calm
512calm
612calm
712light breeze
812light breeze
912light breeze
1012light breeze
1112light breeze
1212light breeze
1312light breeze
1412light breeze
1512light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 14 hours at the start of September to 11 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 168 minutes over September. Sunrise moves from 5:07 AM to 6:21 AM, and sunset from 7:07 PM to 5:32 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
114.05:077:07
213.95:097:04
313.85:127:01
413.75:146:58
513.65:176:54
613.55:196:51
713.45:226:48
813.35:246:45
913.25:276:41
1013.15:306:38
1113.05:326:35
1212.95:356:31
1312.95:376:28
1412.85:406:25
1512.75:426:22
1612.65:456:18
1712.55:476:15
1812.45:506:12
1912.35:526:08
2012.25:556:05
2112.15:586:02
2212.06:005:59
2311.96:035:55
2411.86:055:52
2511.76:085:49
2611.66:105:46
2711.56:135:42
2811.46:155:39
2911.36:185:36
3011.26:215:32

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.37 kWh/m².

For context, solar energy here swings from a low near 0.12 kWh/m² to a high of 5.55 kWh/m² in June across the year — September's 2.37 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.1Moderate
23.0Moderate
33.0Moderate
43.0Moderate
52.9Moderate
62.8Moderate
72.8Moderate
82.7Moderate
92.7Moderate
102.6Moderate
112.6Moderate
122.5Moderate
132.5Moderate
142.4Moderate
152.4Moderate
162.3Moderate
172.3Moderate
182.2Moderate
192.2Moderate
202.1Moderate
212.1Moderate
222.0Moderate
232.0Dim
241.9Dim
251.9Dim
261.8Dim
271.8Dim
281.7Dim
291.7Dim
301.6Dim
Planning a trip in September

Is September a good time to visit Lappeenranta?

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

4.0
Sightseeing
5th-best month of the year
0.3
Beach & pool
4th-best month of the year

September is a reasonable time to visit Lappeenranta for sightseeing.

What to pack for Lappeenranta in September

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

In September, Lappeenranta sees daytime highs around 14°C and nights near 8°C. Worth packing: a warm layer and rain gear. About 11 days see rain.

a warm layerrain gear

Sea temperature near Lappeenranta in September

The nearest coast averages about 15°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 49 km away) is warmest in August at about 18°C and coldest in February near -0°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan1Bracing
Feb0Bracing
Mar0Bracing
Apr1Bracing
May7Bracing
Jun13Bracing
Jul17Cool
Aug18Cool
Sep15Bracing
Oct10Bracing
Nov6Bracing
Dec3Bracing

UV index in Lappeenranta in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Lappeenranta peaks around June 22 at about 5 (moderate) — a little sun protection helps at midday. It bottoms out near December 19 at about 0 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 4 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateLowJun 22UV 5Dec 19UV 0
UV index (midday)Level
Jan0Low
Feb1Low
Mar2Low
Apr3Moderate
May4Moderate
Jun5Moderate
Jul5Moderate
Aug4Moderate
Sep2Moderate
Oct1Low
Nov0Low
Dec0Low
Location & terrain

Where is Lappeenranta?

Lappeenranta sits at 61.1°N, 28.2°E, 104 m above sea level, in Finland. The nearest listed city is Imatra, 33 km away.

HaminaKouvolaAnjalaMikkeliKarhula

Topography around Lappeenranta

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

Within 3 km, the terrain around Lappeenranta has only modest variations in elevation — a maximum elevation change of 180 m around an average of 85 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 188 m; within 80 km, only modest variations in elevation — a maximum elevation change of 242 m.

The land around Lappeenranta is covered by trees (36%), artificial surfaces (29%) and water (27%) within 3 km, trees (63%) and water (20%) within 16 km, and trees (72%) and water (22%) within 80 km.

3 km
180 m
16 km
188 m
80 km
242 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Imatra 33 km · Svetogorsk 37 km · Vyborg 50 km · Hamina 76 km · Kouvola 83 km · Anjala 84 km · Mikkeli 85 km · Karhula 91 km

Finland travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 85% of US
price level, 2025
GDP per capita
$56,149
2025
Happiness
7.8 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1
per 100k, 2023
Road deaths
3.9
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 603
Religion
Lutheran 67%none 31%other 2%Greek Orthodox 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 Lappeenranta (61.0587°, 28.1887°, elevation 104 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).