Klamath Falls weather in September

In September, Klamath Falls sees average daytime highs of 76°F and overnight lows near 48°F, with 0.5 in of rain across 2.6 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 80°F in the first days to 71°F by the end. The sky is clear or mostly clear about 69% 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 Klamath Falls's 3rd-clearest and 10th-windiest month. For the whole year in context, see Klamath Falls's year-round climate.

Daytime high
76°
3rd warmest
Overnight low
48°
10th coldest
Rainfall
0.5 in
2.6 wet days
Daylight
12 h 18 min
5:53 AM – 6:10 PM
Cloud cover
27%
3rd clearest
Wind
4 mph
10th windiest
Solar energy
5.63 kWh/m²
Travel score
8.6
out of 10

Klamath Falls is city in and county seat of Klamath County, Oregon, United States.

Density
400/km²
people per km²
Founded
1905

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 80°F in the first days to 71°F by the end.

A typical September day in Klamath Falls reaches about 76°F in the afternoon and slips back to 48°F overnight — a 28°F spread between the day's warmth and the night's chill. On most days the high lands between 62°F and 86°F. Set against its neighbours, September runs about 8°F cooler than August and about 13°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18052
28051
38051
48051
57951
67951
77950
87850
97850
107849
117749
127749
137649
147649
157648
167548
177548
187547
197447
207447
217447
227446
237346
247346
257346
267245
277245
287145
297144
307044

How September really feels in Klamath Falls

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
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.

Klamath Falls 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
Jan39° / 26°3.211.89.59.30.0
Feb43° / 27°2.5108.410.30.4
Mar48° / 30°2.812.1811.61.8
Apr55° / 34°2.010.14.513.13.5
May65° / 41°1.78.31.114.46.2
Jun74° / 47°0.94.70.1157.9
Jul84° / 55°0.32.1014.87.1
Aug83° / 55°0.41.8013.77.4
Sep76° / 48°0.52.6012.38.6
Oct62° / 40°1.45.7110.86.1
Nov47° / 32°2.79.75.59.61.4
Dec38° / 26°3.912.410.490.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 69% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 18%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
19010
28911
38911
48911
58812
68812
78713
88614
98614
108515
118416
128317
138317
148218
158119
168119
178020
188020
198020
208020
217921
227921
237921
247822
257822
267723
277723
287624
297624
307525

Chance of precipitation in September

Any precipitation

Klamath Falls gets around 0.5 in of rain over 2.6 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 9% and peaks near 11% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
15
25
35
46
56
66
76
87
97
108
118
129
139
149
159
1610
1710
1810
1910
2010
2110
2210
2310
2410
2510
2610
2711
2811
2911
3011

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 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)
1100
2100
3100
4100
5100
6100
7100
8100
9100
10100
11100
12100
13100
14100
15100
16100
17100
18100
19100
20100
21100
22100
23100
24100
25100
26100
27100
28100
29100
30100

Wind in September

Winds average 4 mph in September.

Across September, daily wind ranges from about 4 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
14calm
24calm
34calm
44calm
54calm
64calm
74calm
84calm
94calm
104calm
114calm
124calm
134calm
144calm
154calm
164calm
174calm
184calm
194calm
204calm
214calm
224calm
234calm
244calm
254calm
264calm
274calm
285calm
295calm
305calm

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 5:37 AM to 6:09 AM, and sunset from 6:37 PM to 5:44 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:376:37
213.05:386:35
312.95:396:33
412.95:406:32
512.85:416:30
612.85:426:28
712.75:436:26
812.75:446:24
912.65:456:23
1012.65:476:21
1112.55:486:19
1212.55:496:17
1312.45:506:15
1412.45:516:14
1512.35:526:12
1612.35:536:10
1712.25:546:08
1812.25:556:06
1912.15:566:04
2012.15:576:03
2112.05:586:01
2212.06:005:59
2311.96:015:57
2411.96:025:55
2511.86:035:53
2611.86:045:52
2711.76:055:50
2811.76:065:48
2911.66:075:46
3011.66:095:44

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.63 kWh/m².

For context, solar energy here swings from a low near 1.73 kWh/m² to a high of 8.03 kWh/m² in July across the year — September's 5.63 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.5Intense
26.4Intense
36.4Intense
46.3Intense
56.3Intense
66.2Intense
76.1Intense
86.1Intense
96.0Intense
106.0Bright
115.9Bright
125.8Bright
135.8Bright
145.7Bright
155.6Bright
165.6Bright
175.5Bright
185.5Bright
195.4Bright
205.3Bright
215.3Bright
225.2Bright
235.2Bright
245.1Bright
255.0Bright
265.0Bright
274.9Bright
284.8Bright
294.8Bright
304.7Bright
Planning a trip in September

Hazard calendar for Klamath Falls

In seasonPeak

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

Klamath Falls'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 Klamath Falls?

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

8.6
Sightseeing
1st-best month of the year
7.1
Beach & pool
3rd-best month of the year

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

What to pack for Klamath Falls in September

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

In September, Klamath Falls sees daytime highs around 76°F and nights near 48°F. Worth packing: light clothes and sun protection.

light clothessun protection

UV index in Klamath Falls in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Klamath Falls peaks around July 11 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 12 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 10Dec 12UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5High
Apr6High
May9Very high
Jun9Very high
Jul10Very high
Aug8Very high
Sep6High
Oct5Moderate
Nov2Low
Dec2Low

Air quality in Klamath Falls 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 Klamath Falls is worst in July — around 40 µg/m³ PM2.5 (poor), about 7.4× the cleanest month (January, 5 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecGoodGoodPoorModerateGoodJul 2139 µg/m³Jan 186 µg/m³
PM2.5 (µg/m³)Level
Jan5Good
Feb8Good
Mar9Good
Apr14Moderate
May9Good
Jun7Good
Jul40Poor
Aug33Moderate
Sep38Poor
Oct10Good
Nov8Good
Dec9Good
Location & terrain

Where is Klamath Falls?

Klamath Falls sits at 42.2°N, 121.8°W, 4,108 ft above sea level, in United States. The nearest listed city is Altamont, 2.5 mi away.

Topography around Klamath Falls

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

Within 2 miles, the terrain around Klamath Falls has significant variations in elevation — a maximum elevation change of 896 ft around an average of 4,259 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,126 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 7,894 ft.

The land around Klamath Falls is covered by grassland (47%) and artificial surfaces (29%) within 2 miles, grassland (44%) and trees (30%) within 10 miles, and trees (58%) and grassland (35%) within 50 miles.

2 miles
896 ft
10 miles
2,126 ft
50 miles
7,894 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Altamont 2.5 mi · Ashland 47 mi · Medford 57 mi · Central Point 59 mi · Grants Pass 81 mi · Roseburg 105 mi · Redding 117 mi · Bend 129 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 Klamath Falls (42.2249°, -121.7817°, elevation 4,108 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. 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).