Longview weather in September

In September, Longview sees average daytime highs of 71°F and overnight lows near 50°F, with 2.2 in of rain across 6.7 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 74°F in the first days to 67°F by the end. The sky is clear or mostly clear about 41% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 06 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Longview's 3rd-clearest and 12th-windiest month. For the whole year in context, see Longview's year-round climate.

Daytime high
71°
3rd warmest
Overnight low
50°
10th coldest
Rainfall
2.2 in
6.7 wet days
Daylight
12 h 18 min
5:56 AM – 6:16 PM
Cloud cover
48%
3rd clearest
Wind
4 mph
12th windiest
Solar energy
4.21 kWh/m²
Travel score
7.2
out of 10

Longview is city in Cowlitz County, Washington, United States.

Density
963/km²
people per km²
Founded
1850

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 74°F in the first days to 67°F by the end.

A typical September day in Longview reaches about 71°F in the afternoon and slips back to 50°F overnight — a 21°F spread between the day's warmth and the night's chill. On most days the high lands between 61°F and 82°F. Set against its neighbours, September runs about 6°F cooler than August and about 11°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17452
27452
37452
47452
57452
67352
77352
87351
97351
107351
117251
127251
137251
147151
157150
167150
177150
187050
197049
207049
216949
226949
236949
246948
256848
266848
276848
286747
296747
306647

How September really feels in Longview

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.

Longview weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan46° / 36°7.418.12.68.81.0
Feb49° / 36°5.514.92.1101.7
Mar53° / 38°6.518.21.411.62.4
Apr58° / 41°5.116.40.113.33.5
May64° / 46°3.311.4014.75.5
Jun69° / 50°2.08.5015.56.5
Jul76° / 53°0.63015.28.2
Aug77° / 54°0.83.90148.1
Sep71° / 50°2.26.7012.37.2
Oct60° / 44°5.013010.74.5
Nov50° / 38°8.218.20.89.21.8
Dec45° / 35°8.018.12.78.50.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 41% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 44%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16040
26040
36139
46040
56040
66040
76040
85941
95842
105644
115545
125545
135446
145347
155347
165347
175347
185446
195446
205446
215446
225545
235545
245545
255644
265644
275644
285446
295446
305347

Chance of precipitation in September

Any precipitation

Longview gets around 2.2 in of rain over 6.7 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 23% and peaks near 30% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
117
217
317
417
517
618
718
818
919
1020
1120
1221
1322
1422
1523
1623
1724
1824
1925
2025
2125
2226
2326
2427
2527
2627
2728
2828
2929
3030

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 (%)
172271
272271
372271
472271
573261
674251
774251
875241
975241
1076231
1176231
1277221
1377221
1478211
1578211
1679201
1779201
1880191
1980191
2081181
2182171
2283161
2384151
2485141
2586131
2687121
2788111
2889101
2990100
309190

Wind in September

Winds average 4 mph in September, the calmest month.

Across September, daily wind ranges from about 4 mph on the calmest days to 4 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
284calm
294calm
304calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 96 minutes over September. Sunrise moves from 5:37 AM to 6:15 AM, and sunset from 6:46 PM to 5:47 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.15:376:46
213.15:386:44
313.05:406:42
413.05:416:40
512.95:426:38
612.95:436:36
712.85:456:34
812.85:466:32
912.75:476:30
1012.75:496:28
1112.65:506:26
1212.55:516:24
1312.55:536:22
1412.45:546:20
1512.45:556:18
1612.35:566:16
1712.35:586:14
1812.25:596:12
1912.26:006:10
2012.16:026:08
2112.06:036:05
2212.06:046:03
2311.96:066:01
2411.96:075:59
2511.86:085:57
2611.86:105:55
2711.76:115:53
2811.76:125:51
2911.66:145:49
3011.56:155:47

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.21 kWh/m².

For context, solar energy here swings from a low near 0.95 kWh/m² to a high of 6.37 kWh/m² in July across the year — September's 4.21 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.8Bright
34.8Bright
44.7Bright
54.7Bright
64.7Bright
74.6Bright
84.6Bright
94.5Bright
104.5Bright
114.4Bright
124.4Bright
134.3Bright
144.3Bright
154.2Bright
164.1Bright
174.1Bright
184.0Bright
194.0Moderate
203.9Moderate
213.9Moderate
223.8Moderate
233.8Moderate
243.7Moderate
253.7Moderate
263.6Moderate
273.6Moderate
283.5Moderate
293.4Moderate
303.4Moderate
Planning a trip in September

Hazard calendar for Longview

In seasonPeak

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

Longview's rainy season runs October–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 Longview?

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

7.2
Sightseeing
3rd-best month of the year
4.8
Beach & pool
3rd-best month of the year

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

What to pack for Longview in September

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

In September, Longview sees daytime highs around 71°F and nights near 50°F. Little to plan around — just the basics. About 7 days see rain.

UV index in Longview 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 Longview peaks around July 17 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateVery highVery highHighModerateLowJul 17UV 8Dec 15UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr5Moderate
May8Very high
Jun6High
Jul8Very high
Aug7High
Sep4Moderate
Oct3Moderate
Nov1Low
Dec1Low

Air quality in Longview 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 Longview is worst in September — around 20 µg/m³ PM2.5 (moderate), about 2.7× the cleanest month (December, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1519 µg/m³Dec 237 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar11Good
Apr11Good
May10Good
Jun10Good
Jul9Good
Aug15Moderate
Sep20Moderate
Oct13Moderate
Nov9Good
Dec7Good
Location & terrain

Where is Longview?

Longview sits at 46.1°N, 122.9°W, 20 ft above sea level, in United States. The nearest listed city is Battle Ground, 32 mi away.

Topography around Longview

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

Within 2 miles, the terrain around Longview has only modest variations in elevation — a maximum elevation change of 486 ft around an average of 52 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,946 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 8,212 ft.

The land around Longview is covered by trees (40%) and artificial surfaces (34%) within 2 miles, trees (77%) within 10 miles, and trees (83%) within 50 miles.

2 miles
486 ft
10 miles
1,946 ft
50 miles
8,212 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Battle Ground 32 mi · Salmon Creek 33 mi · Hazel Dell 35 mi · Five Corners 36 mi · Vancouver 37 mi · Orchards 37 mi · Centralia 40 mi · Bethany 40 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 Longview (46.1382°, -122.9382°, elevation 20 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).