Coos Bay weather in September

In September, Coos Bay sees average daytime highs of 67°F and overnight lows near 53°F, with 1.1 in of rain across 4.2 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 68°F in the first days to 65°F by the end. The sky is clear or mostly clear about 58% of the time in September, and the air most often feels dry.

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 Coos Bay's 3rd-clearest and 12th-windiest month. For the whole year in context, see Coos Bay's year-round climate.

Daytime high
67°
3rd warmest
Overnight low
53°
10th coldest
Rainfall
1.1 in
4.2 wet days
Daylight
12 h 18 min
6:02 AM – 6:20 PM
Cloud cover
37%
3rd clearest
Wind
8 mph
12th windiest
Solar energy
4.94 kWh/m²
Travel score
7.4
out of 10

Coos Bay is city in Coos County, Oregon, United States.

Density
393/km²
people per km²
Founded
1853

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 68°F in the first days to 65°F by the end.

A typical September day in Coos Bay reaches about 67°F in the afternoon and slips back to 53°F overnight — a 13°F spread between the day's warmth and the night's chill. On most days the high lands between 61°F and 73°F. Set against its neighbours, September runs about 1°F cooler than August and about 5°F warmer than October.

40°50°60°70°80°151015202530
Avg high (°F)Avg low (°F)
16855
26855
36854
46854
56854
66854
76854
86854
96754
106754
116754
126754
136754
146754
156754
166754
176753
186753
196753
206753
216653
226653
236653
246653
256653
266653
276552
286552
296552
306552

Coos Bay 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 (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan51° / 43°8.117.30.49.22.1
Feb52° / 43°6.214.80.510.22.4
Mar53° / 44°6.616.80.411.62.6
Apr56° / 45°4.614.80.113.23.3
May60° / 49°2.59.5014.54.8
Jun63° / 52°1.35.9015.26.3
Jul67° / 54°0.21.4014.98.0
Aug68° / 55°0.41.9013.88.0
Sep67° / 53°1.14.2012.37.4
Oct61° / 50°3.59.4010.85.4
Nov55° / 46°7.616.80.19.52.9
Dec51° / 43°9.517.60.28.82.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 58% 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 25%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18218
28218
38317
48218
58119
68119
78020
87921
97822
107723
117723
127525
137525
147426
157426
167327
177327
187228
197327
207327
217228
227228
237228
247228
257228
267228
277228
287030
297030
306931

Chance of precipitation in September

Any precipitation

Coos Bay gets around 1.1 in of rain over 4.2 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 15% and peaks near 21% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%151015202530
Rain chance (%)
18
28
38
49
59
69
710
810
911
1012
1113
1214
1314
1415
1516
1616
1717
1817
1917
2018
2118
2219
2319
2419
2519
2620
2720
2820
2921
3021

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 77% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
170300
270300
370300
470300
571290
671290
772280
872280
973270
1073270
1174260
1274260
1375250
1475250
1576240
1677230
1778220
1878211
1979201
2080191
2181181
2281181
2382171
2483161
2584151
2685141
2786131
2887121
2988111
3088111

Wind in September

Winds average 8 mph in September, the calmest month.

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

051015151015202530
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light breeze
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze

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 5:45 AM to 6:19 AM, and sunset from 6:48 PM to 5:54 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:456:48
213.05:466:46
312.95:486:44
412.95:496:42
512.85:506:41
612.85:516:39
712.75:526:37
812.75:536:35
912.65:546:33
1012.65:566:31
1112.55:576:29
1212.55:586:28
1312.45:596:26
1412.46:006:24
1512.36:016:22
1612.36:026:20
1712.26:046:18
1812.26:056:16
1912.16:066:14
2012.16:076:12
2112.06:086:10
2212.06:096:09
2311.96:116:07
2411.96:126:05
2511.86:136:03
2611.86:146:01
2711.76:155:59
2811.76:165:57
2911.66:185:55
3011.66:195:54

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.94 kWh/m².

For context, solar energy here swings from a low near 1.32 kWh/m² to a high of 7.22 kWh/m² in July across the year — September's 4.94 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.7Bright
25.7Bright
35.6Bright
45.6Bright
55.5Bright
65.5Bright
75.4Bright
85.3Bright
95.3Bright
105.2Bright
115.2Bright
125.1Bright
135.0Bright
145.0Bright
154.9Bright
164.9Bright
174.8Bright
184.8Bright
194.7Bright
204.7Bright
214.6Bright
224.5Bright
234.5Bright
244.4Bright
254.4Bright
264.3Bright
274.3Bright
284.2Bright
294.1Bright
304.1Bright
Planning a trip in September

Hazard calendar for Coos Bay

In seasonPeak

None of Coos Bay's seasonal hazards are active in September. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Coos Bay's rainy season runs November–April, when most of the year's rain falls.

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

Is September a good time to visit Coos Bay?

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

7.4
Sightseeing
3rd-best month of the year
3.4
Beach & pool
3rd-best month of the year

September is one of the better times to visit Coos Bay for general sightseeing.

What to pack for Coos Bay in September

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

In September, Coos Bay sees daytime highs around 67°F and nights near 53°F. Worth packing: sun protection. About 4 days see rain.

sun protection

Sea temperature near Coos Bay in September

The nearest coast averages about 56°F 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 8 mi away) is warmest in September at about 56°F and coldest in February near 51°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

50°52°54°56°58°JanFebMarAprMayJunJulAugSepOctNovDecbracing
Sea temperature (°F)Comfort
Jan51Bracing
Feb51Bracing
Mar51Bracing
Apr52Bracing
May53Bracing
Jun55Bracing
Jul55Bracing
Aug56Bracing
Sep56Bracing
Oct55Bracing
Nov53Bracing
Dec52Bracing

UV index in Coos Bay 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 Coos Bay peaks around July 15 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 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 17UV 1
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr5High
May9Very high
Jun8Very high
Jul9Very high
Aug7Very high
Sep5Moderate
Oct4Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Coos Bay?

Coos Bay sits at 43.4°N, 124.2°W, 23 ft above sea level, in United States. The nearest listed city is Roseburg, 45 mi away.

Topography around Coos Bay

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Coos Bay.

Within 2 miles, the terrain around Coos Bay has only modest variations in elevation — a maximum elevation change of 600 ft around an average of 112 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,742 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,088 ft.

The land around Coos Bay is covered by trees (54%) and water (20%) within 2 miles, trees (65%) and water (23%) within 10 miles, and trees (64%) and water (27%) within 50 miles.

2 miles
600 ft
10 miles
1,742 ft
50 miles
4,088 ft
treesgrasslandartificial surfacesbare terrainwaterwetland
September weather nearby: Roseburg 45 mi · Eugene 74 mi · Springfield 76 mi · Grants Pass 78 mi · Central Point 95 mi · Corvallis 96 mi · Medford 99 mi · Albany 104 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

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 Coos Bay (43.3665°, -124.2179°, elevation 23 ft), 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).