Ruhnu weather in September

In September, Ruhnu sees average daytime highs of 15°C and overnight lows near 14°C, with 66 mm of rain across 11.7 wet days and about 12.5 hours of daylight. It is the 3rd-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 17°C in the first days to 13°C by the end. The sky is clear or mostly clear about 27% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 48 min at the start of September to 11 h 18 min by month's end. Set against the rest of the year, September is Ruhnu's 6th-clearest and 6th-windiest month. For the whole year in context, see Ruhnu's year-round climate.

Daytime high: 15°; 3rd warmest
Overnight low: 14°; 10th coldest
Rainfall: 66 mm; 11.7 wet days
Daylight: 12 h 30 min; 6:07 AM – 6:36 PM
Cloud cover: 61%; 6th clearest
Wind: 26 km/h; 6th windiest
Solar energy: 2.89 kWh/m²
Travel score: 4.5; out of 10

← August Ruhnu year-round climate October →Best places to visit in September

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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 13°C by the end.

A typical September day in Ruhnu reaches about 15°C in the afternoon and slips back to 14°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 18°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°C)	18	17	17	17	17	17	17	17	16	16	16	16	16	16	16	15	15	15	15	15	15	15	14	14	14	14	14	14	13	13
Avg low (°C)	16	16	15	15	15	15	15	15	15	14	14	14	14	14	14	14	13	13	13	13	13	13	12	12	12	12	12	12	12	11

	Avg high (°C)	Avg low (°C)
1	18	16
2	17	16
3	17	15
4	17	15
5	17	15
6	17	15
7	17	15
8	17	15
9	16	15
10	16	14
11	16	14
12	16	14
13	16	14
14	16	14
15	16	14
16	15	14
17	15	13
18	15	13
19	15	13
20	15	13
21	15	13
22	15	13
23	14	12
24	14	12
25	14	12
26	14	12
27	14	12
28	14	12
29	13	12
30	13	11

How September really feels in Ruhnu

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

heat index over the day's high

Days feeling ≤ 0°C

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.

Ruhnu weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 4th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	1° / -2°	45	11.9	8.4	7	0.0
Feb	-0° / -3°	37	9.7	7	8.9	0.0
Mar	1° / -1°	33	8.3	4.5	11.4	0.0
Apr	5° / 3°	33	7.4	1.3	14	0.2
May	10° / 8°	34	7.1	0	16.3	2.4
Jun	15° / 13°	57	9.6	0	17.7	4.8
Jul	19° / 17°	60	9.2	0	17.1	6.4
Aug	19° / 17°	79	12	0	15.1	6.0
Sep	15° / 14°	66	11.7	0	12.5	4.5
Oct	10° / 9°	84	14.9	0.2	10	2.1
Nov	6° / 4°	69	14.1	2.3	7.6	0.5
Dec	3° / 1°	56	13.5	6.7	6.3	0.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 27% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 56%. Skies tend to cloud over as the month goes on.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	46	47	45	45	46	45	45	45	45	45	46	45	45	46	46	45	45	44	44	44	44	43	42	41	41	41	39	38	38	38
Cloudier (%)	54	53	55	55	54	55	55	55	55	55	54	55	55	54	54	55	55	56	56	56	56	57	58	59	59	59	61	62	62	62

	Clearer (%)	Cloudier (%)
1	46	54
2	47	53
3	45	55
4	45	55
5	46	54
6	45	55
7	45	55
8	45	55
9	45	55
10	45	55
11	46	54
12	45	55
13	45	55
14	46	54
15	46	54
16	45	55
17	45	55
18	44	56
19	44	56
20	44	56
21	44	56
22	43	57
23	42	58
24	41	59
25	41	59
26	41	59
27	39	61
28	38	62
29	38	62
30	38	62

Chance of precipitation in September

Any precipitation

Ruhnu gets around 66 mm of rain over 11.7 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 40% and peaks near 43% on the wettest days.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	42	41	41	41	40	40	40	40	40	40	40	39	39	39	39	39	39	39	39	39	39	39	39	39	39	40	40	41	42	43

	Rain chance (%)
1	42
2	41
3	41
4	41
5	40
6	40
7	40
8	40
9	40
10	40
11	40
12	39
13	39
14	39
15	39
16	39
17	39
18	39
19	39
20	39
21	39
22	39
23	39
24	39
25	39
26	40
27	40
28	41
29	42
30	43

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 74% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Dry (%)	48	49	51	53	54	56	58	60	62	64	67	69	71	74	76	78	81	82	84	85	87	88	88	89	89	90	91	91	92	93
Comfortable (%)	42	41	41	40	39	38	37	35	34	32	30	28	26	24	22	20	18	17	15	14	13	12	12	11	11	10	9	9	8	7
Humid (%)	10	9	8	7	7	6	5	5	4	4	3	3	3	2	2	2	1	1	1	1	0	0	0	0	0	0	0	0	0	0

	Dry (%)	Comfortable (%)	Humid (%)
1	48	42	10
2	49	41	9
3	51	41	8
4	53	40	7
5	54	39	7
6	56	38	6
7	58	37	5
8	60	35	5
9	62	34	4
10	64	32	4
11	67	30	3
12	69	28	3
13	71	26	3
14	74	24	2
15	76	22	2
16	78	20	2
17	81	18	1
18	82	17	1
19	84	15	1
20	85	14	1
21	87	13	0
22	88	12	0
23	88	12	0
24	89	11	0
25	89	11	0
26	90	10	0
27	91	9	0
28	91	9	0
29	92	8	0
30	93	7	0

Wind in September

Winds average 26 km/h in September.

Across September, daily wind ranges from about 24 km/h on the calmest days to 28 km/h at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (km/h)	24	24	24	24	25	25	25	25	25	26	26	26	26	26	26	26	27	27	27	27	27	27	27	27	27	27	27	27	28	28
Feels	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy	breezy

	Wind speed (km/h)	Feels
1	24	breezy
2	24	breezy
3	24	breezy
4	24	breezy
5	25	breezy
6	25	breezy
7	25	breezy
8	25	breezy
9	25	breezy
10	26	breezy
11	26	breezy
12	26	breezy
13	26	breezy
14	26	breezy
15	26	breezy
16	26	breezy
17	27	breezy
18	27	breezy
19	27	breezy
20	27	breezy
21	27	breezy
22	27	breezy
23	27	breezy
24	27	breezy
25	27	breezy
26	27	breezy
27	27	breezy
28	27	breezy
29	28	breezy
30	28	breezy

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 48 min at the start of September to 11 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 150 minutes over September. Sunrise moves from 5:34 AM to 6:37 AM, and sunset from 7:20 PM to 5:55 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	13.8	13.7	13.6	13.5	13.4	13.3	13.3	13.2	13.1	13.0	12.9	12.8	12.7	12.7	12.6	12.5	12.4	12.3	12.2	12.1	12.1	12.0	11.9	11.8	11.7	11.6	11.6	11.5	11.4	11.3
Sunrise (AM)	5:34	5:36	5:38	5:40	5:43	5:45	5:47	5:49	5:51	5:53	5:56	5:58	6:00	6:02	6:04	6:07	6:09	6:11	6:13	6:15	6:18	6:20	6:22	6:24	6:26	6:29	6:31	6:33	6:35	6:37
Sunset (PM)	7:20	7:17	7:14	7:11	7:08	7:05	7:02	6:59	6:57	6:54	6:51	6:48	6:45	6:42	6:39	6:36	6:33	6:30	6:27	6:24	6:21	6:18	6:16	6:13	6:10	6:07	6:04	6:01	5:58	5:55

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.8	5:34	7:20
2	13.7	5:36	7:17
3	13.6	5:38	7:14
4	13.5	5:40	7:11
5	13.4	5:43	7:08
6	13.3	5:45	7:05
7	13.3	5:47	7:02
8	13.2	5:49	6:59
9	13.1	5:51	6:57
10	13.0	5:53	6:54
11	12.9	5:56	6:51
12	12.8	5:58	6:48
13	12.7	6:00	6:45
14	12.7	6:02	6:42
15	12.6	6:04	6:39
16	12.5	6:07	6:36
17	12.4	6:09	6:33
18	12.3	6:11	6:30
19	12.2	6:13	6:27
20	12.1	6:15	6:24
21	12.1	6:18	6:21
22	12.0	6:20	6:18
23	11.9	6:22	6:16
24	11.8	6:24	6:13
25	11.7	6:26	6:10
26	11.6	6:29	6:07
27	11.6	6:31	6:04
28	11.5	6:33	6:01
29	11.4	6:35	5:58
30	11.3	6:37	5:55

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.89 kWh/m².

For context, solar energy here swings from a low near 0.26 kWh/m² to a high of 6.22 kWh/m² in June across the year — September's 2.89 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	3.7	3.6	3.6	3.5	3.5	3.4	3.4	3.3	3.3	3.2	3.1	3.1	3.0	3.0	2.9	2.9	2.8	2.8	2.7	2.6	2.6	2.5	2.5	2.5	2.4	2.4	2.3	2.2	2.2	2.1
Level	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	3.7	Moderate
2	3.6	Moderate
3	3.6	Moderate
4	3.5	Moderate
5	3.5	Moderate
6	3.4	Moderate
7	3.4	Moderate
8	3.3	Moderate
9	3.3	Moderate
10	3.2	Moderate
11	3.1	Moderate
12	3.1	Moderate
13	3.0	Moderate
14	3.0	Moderate
15	2.9	Moderate
16	2.9	Moderate
17	2.8	Moderate
18	2.8	Moderate
19	2.7	Moderate
20	2.6	Moderate
21	2.6	Moderate
22	2.5	Moderate
23	2.5	Moderate
24	2.5	Moderate
25	2.4	Moderate
26	2.4	Moderate
27	2.3	Moderate
28	2.2	Moderate
29	2.2	Moderate
30	2.1	Moderate

Planning a trip in September

Is September a good time to visit Ruhnu?

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

4.5

Sightseeing

4th-best month of the year

0.5

Beach & pool

3rd-best month of the year

September is a reasonable time to visit Ruhnu for sightseeing.

What to pack for Ruhnu in September

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

In September, Ruhnu sees daytime highs around 15°C and nights near 14°C. Worth packing: a warm layer, rain gear and a windbreaker. About 12 days see rain.

a warm layerrain geara windbreaker

Sea temperature near Ruhnu 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 offshore is warmest in August at about 18°C and coldest in February near 1°C.

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Sea temperature (°C)	2	1	1	3	7	13	17	18	15	11	8	5
Comfort	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Cool	Cool	Cool	Bracing	Bracing	Bracing

	Sea temperature (°C)	Comfort
Jan	2	Bracing
Feb	1	Bracing
Mar	1	Bracing
Apr	3	Bracing
May	7	Bracing
Jun	13	Bracing
Jul	17	Cool
Aug	18	Cool
Sep	15	Cool
Oct	11	Bracing
Nov	8	Bracing
Dec	5	Bracing

UV index in Ruhnu in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 3. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Ruhnu 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 5 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	0	1	2	3	4	6	5	5	3	1	1	0
Level	Low	Low	Low	Moderate	Moderate	High	Moderate	Moderate	Moderate	Low	Low	Low

	UV index (midday)	Level
Jan	0	Low
Feb	1	Low
Mar	2	Low
Apr	3	Moderate
May	4	Moderate
Jun	6	High
Jul	5	Moderate
Aug	5	Moderate
Sep	3	Moderate
Oct	1	Low
Nov	1	Low
Dec	0	Low

Location & terrain

Where is Ruhnu?

Ruhnu sits at 57.8°N, 23.2°E, 0 m above sea level, in Estonia. The nearest listed city is Kuressaare, 67 km away.

Topography around Ruhnu

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

Within 3 km, the terrain around Ruhnu has only modest variations in elevation — a maximum elevation change of 38 m around an average of 4 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 38 m; within 80 km, only modest variations in elevation — a maximum elevation change of 184 m.

The land around Ruhnu is covered by water (63%) and trees (23%) within 3 km, water (99%) within 16 km, and water (70%) and trees (21%) within 80 km.

3 km

38 m

water 63%

16 km

38 m

water 99%

80 km

184 m

water 70%

treesgrasslandcroplandwaterwetland

← August Ruhnu year-round climate October →Best places to visit in September

September weather nearby: Kuressaare 67 km · Muhu 89 km · Tukums 93 km · Jūrmala 98 km · Pärnu 98 km · Riga 108 km · Dārzciems 110 km · Ventspils 110 km

Estonia travel facts

Travel advisory: Level 1; Exercise Normal Precautions
Power plugs: Type C / F; 230 V · 50 Hz
Prices: ≈ 66% of US; price level, 2025
GDP per capita: $34,418; 2025
Happiness: 6.4 / 10; World Happiness, 2025
Safe drinking water: 99%; of population, 2024
Homicide rate: 1.5; per 100k, 2023
Road deaths: 4.5; per 100k/yr, 2019
Income group: High; World Bank
English: High; EF EPI 561
Religion

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 Ruhnu (57.8003°, 23.2483°, elevation 0 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).

	Avg high (°C)	Avg low (°C)
1	18	16
2	17	16
3	17	15
4	17	15
5	17	15
6	17	15
7	17	15
8	17	15
9	16	15
10	16	14
11	16	14
12	16	14
13	16	14
14	16	14
15	16	14
16	15	14
17	15	13
18	15	13
19	15	13
20	15	13
21	15	13
22	15	13
23	14	12
24	14	12
25	14	12
26	14	12
27	14	12
28	14	12
29	13	12
30	13	11

	Clearer (%)	Cloudier (%)
1	46	54
2	47	53
3	45	55
4	45	55
5	46	54
6	45	55
7	45	55
8	45	55
9	45	55
10	45	55
11	46	54
12	45	55
13	45	55
14	46	54
15	46	54
16	45	55
17	45	55
18	44	56
19	44	56
20	44	56
21	44	56
22	43	57
23	42	58
24	41	59
25	41	59
26	41	59
27	39	61
28	38	62
29	38	62
30	38	62

	Rain chance (%)
1	42
2	41
3	41
4	41
5	40
6	40
7	40
8	40
9	40
10	40
11	40
12	39
13	39
14	39
15	39
16	39
17	39
18	39
19	39
20	39
21	39
22	39
23	39
24	39
25	39
26	40
27	40
28	41
29	42
30	43

	Dry (%)	Comfortable (%)	Humid (%)
1	48	42	10
2	49	41	9
3	51	41	8
4	53	40	7
5	54	39	7
6	56	38	6
7	58	37	5
8	60	35	5
9	62	34	4
10	64	32	4
11	67	30	3
12	69	28	3
13	71	26	3
14	74	24	2
15	76	22	2
16	78	20	2
17	81	18	1
18	82	17	1
19	84	15	1
20	85	14	1
21	87	13	0
22	88	12	0
23	88	12	0
24	89	11	0
25	89	11	0
26	90	10	0
27	91	9	0
28	91	9	0
29	92	8	0
30	93	7	0

	Avg high (°C)	Avg low (°C)
1	18	16
2	17	16
3	17	15
4	17	15
5	17	15
6	17	15
7	17	15
8	17	15
9	16	15
10	16	14
11	16	14
12	16	14
13	16	14
14	16	14
15	16	14
16	15	14
17	15	13
18	15	13
19	15	13
20	15	13
21	15	13
22	15	13
23	14	12
24	14	12
25	14	12
26	14	12
27	14	12
28	14	12
29	13	12
30	13	11

	Clearer (%)	Cloudier (%)
1	46	54
2	47	53
3	45	55
4	45	55
5	46	54
6	45	55
7	45	55
8	45	55
9	45	55
10	45	55
11	46	54
12	45	55
13	45	55
14	46	54
15	46	54
16	45	55
17	45	55
18	44	56
19	44	56
20	44	56
21	44	56
22	43	57
23	42	58
24	41	59
25	41	59
26	41	59
27	39	61
28	38	62
29	38	62
30	38	62

	Rain chance (%)
1	42
2	41
3	41
4	41
5	40
6	40
7	40
8	40
9	40
10	40
11	40
12	39
13	39
14	39
15	39
16	39
17	39
18	39
19	39
20	39
21	39
22	39
23	39
24	39
25	39
26	40
27	40
28	41
29	42
30	43

	Dry (%)	Comfortable (%)	Humid (%)
1	48	42	10
2	49	41	9
3	51	41	8
4	53	40	7
5	54	39	7
6	56	38	6
7	58	37	5
8	60	35	5
9	62	34	4
10	64	32	4
11	67	30	3
12	69	28	3
13	71	26	3
14	74	24	2
15	76	22	2
16	78	20	2
17	81	18	1
18	82	17	1
19	84	15	1
20	85	14	1
21	87	13	0
22	88	12	0
23	88	12	0
24	89	11	0
25	89	11	0
26	90	10	0
27	91	9	0
28	91	9	0
29	92	8	0
30	93	7	0

	Avg high (°C)	Avg low (°C)
1	18	16
2	17	16
3	17	15
4	17	15
5	17	15
6	17	15
7	17	15
8	17	15
9	16	15
10	16	14
11	16	14
12	16	14
13	16	14
14	16	14
15	16	14
16	15	14
17	15	13
18	15	13
19	15	13
20	15	13
21	15	13
22	15	13
23	14	12
24	14	12
25	14	12
26	14	12
27	14	12
28	14	12
29	13	12
30	13	11

	Clearer (%)	Cloudier (%)
1	46	54
2	47	53
3	45	55
4	45	55
5	46	54
6	45	55
7	45	55
8	45	55
9	45	55
10	45	55
11	46	54
12	45	55
13	45	55
14	46	54
15	46	54
16	45	55
17	45	55
18	44	56
19	44	56
20	44	56
21	44	56
22	43	57
23	42	58
24	41	59
25	41	59
26	41	59
27	39	61
28	38	62
29	38	62
30	38	62

	Rain chance (%)
1	42
2	41
3	41
4	41
5	40
6	40
7	40
8	40
9	40
10	40
11	40
12	39
13	39
14	39
15	39
16	39
17	39
18	39
19	39
20	39
21	39
22	39
23	39
24	39
25	39
26	40
27	40
28	41
29	42
30	43

	Dry (%)	Comfortable (%)	Humid (%)
1	48	42	10
2	49	41	9
3	51	41	8
4	53	40	7
5	54	39	7
6	56	38	6
7	58	37	5
8	60	35	5
9	62	34	4
10	64	32	4
11	67	30	3
12	69	28	3
13	71	26	3
14	74	24	2
15	76	22	2
16	78	20	2
17	81	18	1
18	82	17	1
19	84	15	1
20	85	14	1
21	87	13	0
22	88	12	0
23	88	12	0
24	89	11	0
25	89	11	0
26	90	10	0
27	91	9	0
28	91	9	0
29	92	8	0
30	93	7	0