Lake Stevens weather in September

In September, Lake Stevens sees average daytime highs of 67°F and overnight lows near 49°F, with 4.0 in of rain across 9.2 wet days and about 12.4 hours of daylight. It is the 3rd-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 71°F in the first days to 64°F by the end. The sky is clear or mostly clear about 40% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 12 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Lake Stevens's 3rd-clearest and 10th-windiest month. For the whole year in context, see Lake Stevens's year-round climate.

Daytime high
67°
3rd warmest
Overnight low
49°
9th coldest
Rainfall
4.0 in
9.2 wet days
Daylight
12 h 18 min
5:52 AM – 6:13 PM
Cloud cover
50%
3rd clearest
Wind
4 mph
10th windiest
Solar energy
3.98 kWh/m²
Travel score
6.5
out of 10

Lake Stevens is city in Snohomish County, Washington, United States.

Density
1,342/km²
people per km²
Founded
1889

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 71°F in the first days to 64°F by the end.

A typical September day in Lake Stevens reaches about 67°F in the afternoon and slips back to 49°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 59°F and 77°F. Set against its neighbours, September runs about 6°F cooler than August and about 10°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17151
27151
37151
47051
57051
67051
77050
86950
96950
106950
116950
126850
136849
146849
156849
166749
176749
186749
196748
206648
216648
226648
236547
246547
256547
266547
276447
286446
296446
306346

How September really feels in Lake Stevens

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.

Lake Stevens 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
Jan44° / 35°11.019.55.58.60.6
Feb47° / 35°7.115.74.69.91.3
Mar51° / 37°8.619.83.611.62.0
Apr57° / 41°6.517.10.913.43.2
May63° / 46°4.3130.114.95.0
Jun66° / 50°3.410.7015.85.9
Jul73° / 54°1.66.2015.47.6
Aug73° / 53°1.85.7014.17.8
Sep67° / 49°4.09.2012.46.5
Oct57° / 43°8.715.4010.63.7
Nov48° / 37°12.019.62.191.4
Dec43° / 34°10.619.268.20.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 40% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 45%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16040
26040
36040
46040
56040
66040
76040
85941
95842
105743
115644
125545
135545
145446
155446
165446
175446
185347
195347
205347
215347
225347
235347
245248
255347
265347
275347
285248
295149
305149

Chance of precipitation in September

Any precipitation

Lake Stevens gets around 4.0 in of rain over 9.2 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 31% and peaks near 33% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
127
228
328
428
529
629
729
830
930
1031
1131
1232
1332
1433
1533
1633
1733
1833
1933
2033
2133
2233
2332
2432
2532
2632
2732
2832
2933
3033

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 84% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
175241
276231
377230
478220
578220
679210
779210
880200
980200
1081190
1181190
1282180
1382180
1483170
1583170
1684160
1785150
1886140
1986140
2087130
2188120
2289110
2389110
2490100
259190
269280
279280
289370
299460
309460

Wind in September

Winds average 4 mph in September.

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 12 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 102 minutes over September. Sunrise moves from 5:31 AM to 6:12 AM, and sunset from 6:45 PM to 5:43 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.25:316:45
213.25:336:43
313.15:346:41
413.15:356:39
513.05:376:36
612.95:386:34
712.95:406:32
812.85:416:30
912.85:426:28
1012.75:446:26
1112.65:456:24
1212.65:476:22
1312.55:486:19
1412.55:496:17
1512.45:516:15
1612.35:526:13
1712.35:546:11
1812.25:556:09
1912.25:576:06
2012.15:586:04
2112.05:596:02
2212.06:016:00
2311.96:025:58
2411.96:045:56
2511.86:055:53
2611.76:075:51
2711.76:085:49
2811.66:095:47
2911.66:115:45
3011.56:125:43

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.98 kWh/m².

For context, solar energy here swings from a low near 0.83 kWh/m² to a high of 6.11 kWh/m² in July across the year — September's 3.98 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.6Bright
34.6Bright
44.5Bright
54.5Bright
64.5Bright
74.4Bright
84.4Bright
94.3Bright
104.3Bright
114.2Bright
124.1Bright
134.1Bright
144.0Bright
154.0Moderate
163.9Moderate
173.9Moderate
183.8Moderate
193.7Moderate
203.7Moderate
213.6Moderate
223.6Moderate
233.5Moderate
243.5Moderate
253.4Moderate
263.4Moderate
273.3Moderate
283.3Moderate
293.2Moderate
303.1Moderate
Planning a trip in September

Hazard calendar for Lake Stevens

In seasonPeak

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

Lake Stevens'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 Lake Stevens?

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

6.5
Sightseeing
3rd-best month of the year
3.2
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Lake Stevens for sightseeing.

What to pack for Lake Stevens in September

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

In September, Lake Stevens sees daytime highs around 67°F and nights near 49°F. Worth packing: rain gear. About 9 days see rain.

rain gear

Sea temperature near Lake Stevens in September

The nearest coast averages about 53°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 39 mi away) is warmest in August at about 53°F and coldest in February near 46°F.

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

45°50°55°JanFebMarAprMayJunJulAugSepOctNovDecbracing
Sea temperature (°F)Comfort
Jan46Bracing
Feb46Bracing
Mar47Bracing
Apr48Bracing
May50Bracing
Jun52Bracing
Jul53Bracing
Aug53Bracing
Sep53Bracing
Oct50Bracing
Nov49Bracing
Dec47Bracing

UV index in Lake Stevens 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 Lake Stevens peaks around July 17 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 18 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 17UV 8Dec 18UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar4Moderate
Apr5Moderate
May7High
Jun6High
Jul8Very high
Aug6High
Sep4Moderate
Oct3Moderate
Nov1Low
Dec1Low

Air quality in Lake Stevens 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 Lake Stevens is worst in August — around 20 µg/m³ PM2.5 (moderate), about 3.1× the cleanest month (December, 6 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodGoodModerateGoodModerateGoodAug 2119 µg/m³Dec 157 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb10Good
Mar12Moderate
Apr12Good
May13Moderate
Jun11Good
Jul10Good
Aug20Moderate
Sep18Moderate
Oct11Good
Nov7Good
Dec6Good
Location & terrain

Where is Lake Stevens?

Lake Stevens sits at 48.0°N, 122.1°W, 217 ft above sea level, in United States. The nearest listed city is West Lake Stevens, 2.5 mi away.

Topography around Lake Stevens

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

Within 2 miles, the terrain around Lake Stevens has only modest variations in elevation — a maximum elevation change of 361 ft around an average of 276 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,382 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 10,427 ft.

The land around Lake Stevens is covered by trees (66%) within 2 miles, trees (68%) within 10 miles, and trees (71%) within 50 miles.

2 miles
361 ft
10 miles
2,382 ft
50 miles
10,427 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: West Lake Stevens 2.5 mi · Marysville 5.6 mi · Everett 6.8 mi · Eastmont 9.9 mi · Silver Firs 11 mi · Monroe 12 mi · Mukilteo 12 mi · Mill Creek 12 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 Lake Stevens (48.0151°, -122.0637°, elevation 217 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. 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).