Rumia weather in September

In September, Rumia sees average daytime highs of 17°C and overnight lows near 11°C, with 65 mm of rain across 11.4 wet days and about 12.5 hours of daylight. It is the 4th-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 19°C in the first days to 15°C by the end. The sky is clear or mostly clear about 21% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 36 min at the start of September to 11 h 24 min by month's end. Set against the rest of the year, September is Rumia's 6th-clearest and 7th-windiest month. For the whole year in context, see Rumia's year-round climate.

Daytime high
17°
4th warmest
Overnight low
11°
9th coldest
Rainfall
65 mm
11.4 wet days
Daylight
12 h 24 min
5:28 AM – 5:54 PM
Cloud cover
64%
6th clearest
Wind
17 km/h
7th windiest
Solar energy
2.96 kWh/m²
Travel score
5.0
out of 10

Rumia is city and urban gmina in the Kashubia region of north-western Poland.

Density
1,363/km²
people per km²
Founded
1224

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 19°C in the first days to 15°C by the end.

A typical September day in Rumia reaches about 17°C in the afternoon and slips back to 11°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 21°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11913
21913
31913
41813
51812
61812
71812
81812
91812
101812
111712
121712
131711
141711
151711
161711
171711
181611
191611
201611
211610
221610
231610
241610
251510
261510
271510
281510
29159
30159

How September really feels in Rumia

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.

Rumia weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -2°4711.96.57.60.0
Feb / -2°3810.16.19.30.0
Mar / 4410.84.411.50.2
Apr10° / 429.31.113.72.2
May14° / 6211.1015.84.2
Jun18° / 12°7312.8016.95.4
Jul20° / 14°9213.6016.45.9
Aug21° / 14°8112.6014.76.1
Sep17° / 11°6511.4012.55.0
Oct12° / 6311.90.210.22.8
Nov / 5011.728.20.6
Dec / -0°5211.957.10.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% 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 60%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14555
24357
34357
44258
54258
64159
74060
83961
93961
103961
113961
123961
134060
143961
153961
163961
173961
183961
194060
204060
214060
224060
234159
244159
254159
264159
274159
284159
294159
304060

Chance of precipitation in September

Any precipitation

Rumia gets around 65 mm of rain over 11.4 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 39% and peaks near 47% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
147
247
347
447
547
646
746
845
944
1043
1142
1241
1340
1439
1537
1636
1735
1834
1934
2033
2133
2232
2332
2432
2533
2633
2733
2834
2935
3036

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 79% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
156368
258357
360337
461327
563307
665296
767276
868266
971245
1072235
1174215
1276204
1377194
1480173
1581163
1682153
1784142
1885132
1987121
2087121
2188111
2289101
2390100
249190
259190
269190
279280
289280
299280
309280

Wind in September

Winds average 17 km/h in September.

Across September, daily wind ranges from about 16 km/h on the calmest days to 19 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202530
Wind speed (km/h)Feels
116light breeze
217light breeze
317light breeze
417light breeze
517light breeze
617light breeze
717light breeze
817light breeze
917light breeze
1017light breeze
1117light breeze
1217light breeze
1317light breeze
1417light breeze
1517light breeze
1617light breeze
1718light breeze
1818light breeze
1918light breeze
2018light breeze
2118light breeze
2218light breeze
2318light breeze
2418light breeze
2518light breeze
2618light breeze
2718light breeze
2818light breeze
2918light breeze
3019light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 36 min at the start of September to 11 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 132 minutes over September. Sunrise moves from 4:59 AM to 5:54 AM, and sunset from 6:33 PM to 5:17 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.64:596:33
213.55:016:30
313.45:036:28
413.35:056:25
513.35:076:23
613.25:096:20
713.15:116:17
813.05:136:15
913.05:156:12
1012.95:166:10
1112.85:186:07
1212.75:206:04
1312.75:226:02
1412.65:245:59
1512.55:265:56
1612.45:285:54
1712.45:305:51
1812.35:325:49
1912.25:335:46
2012.15:355:43
2112.15:375:41
2212.05:395:38
2311.95:415:35
2411.85:435:33
2511.85:455:30
2611.75:475:27
2711.65:495:25
2811.55:515:22
2911.55:535:20
3011.45:545:17

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.96 kWh/m².

For context, solar energy here swings from a low near 0.43 kWh/m² to a high of 5.73 kWh/m² in June across the year — September's 2.96 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.7Moderate
23.6Moderate
33.5Moderate
43.5Moderate
53.4Moderate
63.4Moderate
73.3Moderate
83.3Moderate
93.2Moderate
103.2Moderate
113.1Moderate
123.1Moderate
133.0Moderate
143.0Moderate
153.0Moderate
162.9Moderate
172.9Moderate
182.9Moderate
192.8Moderate
202.8Moderate
212.7Moderate
222.7Moderate
232.7Moderate
242.6Moderate
252.6Moderate
262.5Moderate
272.5Moderate
282.4Moderate
292.4Moderate
302.3Moderate
Planning a trip in September

Is September a good time to visit Rumia?

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

5.0
Sightseeing
4th-best month of the year
1.1
Beach & pool
4th-best month of the year

September is a reasonable time to visit Rumia for sightseeing.

What to pack for Rumia in September

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

In September, Rumia sees daytime highs around 17°C and nights near 11°C. Worth packing: a warm layer and rain gear. About 11 days see rain.

a warm layerrain gear

Sea temperature near Rumia in September

The nearest coast averages about 16°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 16 km away) is warmest in August at about 19°C and coldest in February near 3°C.

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

0°5°10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan4Bracing
Feb3Bracing
Mar3Bracing
Apr5Bracing
May9Bracing
Jun14Bracing
Jul17Cool
Aug19Cool
Sep16Cool
Oct13Bracing
Nov9Bracing
Dec6Bracing

UV index in Rumia in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Rumia peaks around June 19 at about 6 (high) — a little sun protection helps at midday. It bottoms out near December 20 at about 0 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 6 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJun 19UV 6Dec 20UV 0
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May5Moderate
Jun6High
Jul6High
Aug5Moderate
Sep4Moderate
Oct2Low
Nov1Low
Dec0Low
Location & terrain

Where is Rumia?

Rumia sits at 54.6°N, 18.4°E, 23 m above sea level, in Poland. The nearest listed city is Reda, 5.0 km away.

Topography around Rumia

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

Within 3 km, the terrain around Rumia has only modest variations in elevation — a maximum elevation change of 178 m around an average of 58 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 248 m; within 80 km, significant variations in elevation — a maximum elevation change of 339 m.

The land around Rumia is covered by trees (53%) and artificial surfaces (24%) within 3 km, trees (45%) within 16 km, and water (40%), trees (26%) and cropland (22%) within 80 km.

3 km
178 m
16 km
248 m
80 km
339 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Reda 5.0 km · Wejherowo 11 km · Gdynia 11 km · Osowa 16 km · Sopot 18 km · Przymorze Wielkie 22 km · Wrzeszcz Górny 25 km · Wrzeszcz Dolny 25 km

Poland travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / E
230 V · 50 Hz
Prices
≈ 52% of US
price level, 2025
GDP per capita
$28,420
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
89%
of population, 2024
Homicide rate
0.8
per 100k, 2023
Road deaths
9.4
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 600
Religion
Roman Catholic 71%refused to answer 21%no religion 7%

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 Rumia (54.5709°, 18.388°, 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).