Gresham weather in September

In September, Gresham sees average daytime highs of 74°F and overnight lows near 52°F, with 2.3 in of rain across 6.4 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 78°F in the first days to 70°F by the end. The sky is clear or mostly clear about 47% 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 Gresham's 3rd-clearest and 10th-windiest month. For the whole year in context, see Gresham's year-round climate.

Daytime high
74°
3rd warmest
Overnight low
52°
10th coldest
Rainfall
2.3 in
6.4 wet days
Daylight
12 h 18 min
5:55 AM – 6:13 PM
Cloud cover
43%
3rd clearest
Wind
4 mph
10th windiest
Solar energy
4.51 kWh/m²
Travel score
7.6
out of 10

Gresham is city in Multnomah County, Oregon, United States of America.

Density
1,822/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 78°F in the first days to 70°F by the end.

A typical September day in Gresham reaches about 74°F in the afternoon and slips back to 52°F overnight — a 22°F spread between the day's warmth and the night's chill. On most days the high lands between 64°F and 87°F. Set against its neighbours, September runs about 7°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17855
27855
37854
47854
57854
67754
77754
87754
97653
107653
117653
127653
137553
147553
157552
167452
177452
187452
197351
207351
217351
227351
237251
247250
257150
267150
277150
287049
297049
306949

How September really feels in Gresham

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.

Gresham 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
Jan46° / 36°8.718.33.78.91.0
Feb50° / 37°6.515.63.210.11.8
Mar55° / 39°7.018.22.211.62.7
Apr60° / 42°5.616.60.213.23.9
May67° / 47°3.511.6014.75.8
Jun72° / 52°2.39015.46.8
Jul80° / 56°0.62.9015.17.9
Aug81° / 56°0.82.9013.97.9
Sep74° / 52°2.36.4012.37.6
Oct62° / 45°5.812.9010.75.0
Nov51° / 40°9.0181.19.32.1
Dec45° / 36°9.618.43.68.60.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 47% 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 37%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17030
27030
36931
46832
56931
66832
76733
86634
96535
106436
116337
126337
136238
146139
156139
166139
176139
186139
196139
206139
216139
226139
236040
246139
256139
266139
276139
285941
295941
305842

Chance of precipitation in September

Any precipitation

Gresham gets around 2.3 in of rain over 6.4 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 22% 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 (%)
114
214
315
415
516
616
717
817
918
1019
1120
1221
1321
1422
1522
1623
1723
1824
1924
2025
2125
2226
2326
2426
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 84% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
177221
277221
378211
478211
579201
679201
780191
880191
981181
1081181
1182171
1282171
1383161
1483161
1584151
1684151
1784151
1885141
1985141
2086131
2186131
2287121
2387121
2488111
2589101
2689101
279091
289091
299181
309181

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 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 5:36 AM to 6:13 AM, and sunset from 6:43 PM to 5:46 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.15:366:43
213.15:376:41
313.05:386:39
413.05:396:37
512.95:416:35
612.95:426:33
712.85:436:31
812.75:456:29
912.75:466:27
1012.65:476:26
1112.65:486:24
1212.55:506:22
1312.55:516:20
1412.45:526:18
1512.45:536:15
1612.35:556:13
1712.35:566:11
1812.25:576:09
1912.25:586:07
2012.16:006:05
2112.06:016:03
2212.06:026:01
2311.96:045:59
2411.96:055:57
2511.86:065:55
2611.86:075:53
2711.76:095:51
2811.76:105:49
2911.66:115:47
3011.56:135:46

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.51 kWh/m².

For context, solar energy here swings from a low near 1.02 kWh/m² to a high of 6.96 kWh/m² in July across the year — September's 4.51 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.3Bright
25.2Bright
35.2Bright
45.1Bright
55.1Bright
65.0Bright
75.0Bright
84.9Bright
94.9Bright
104.8Bright
114.7Bright
124.7Bright
134.6Bright
144.5Bright
154.5Bright
164.4Bright
174.4Bright
184.3Bright
194.3Bright
204.2Bright
214.2Bright
224.1Bright
234.0Bright
244.0Moderate
253.9Moderate
263.9Moderate
273.8Moderate
283.7Moderate
293.7Moderate
303.6Moderate
Planning a trip in September

Hazard calendar for Gresham

In seasonPeak

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

Gresham'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 Gresham?

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

7.6
Sightseeing
3rd-best month of the year
6.0
Beach & pool
3rd-best month of the year

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

What to pack for Gresham in September

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

In September, Gresham sees daytime highs around 74°F and nights near 52°F. Worth packing: light clothes and sun protection. About 6 days see rain.

light clothessun protection

UV index in Gresham 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 Gresham 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
Jun7High
Jul8Very high
Aug7High
Sep4Moderate
Oct3Moderate
Nov1Low
Dec1Low

Air quality in Gresham 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 Gresham is worst in August — around 35 µg/m³ PM2.5 (moderate), about 6.3× the cleanest month (December, 6 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 2334 µg/m³Dec 226 µg/m³
PM2.5 (µg/m³)Level
Jan6Good
Feb7Good
Mar10Good
Apr10Good
May9Good
Jun8Good
Jul8Good
Aug35Moderate
Sep33Moderate
Oct11Good
Nov8Good
Dec6Good
Location & terrain

Where is Gresham?

Gresham sits at 45.5°N, 122.4°W, 318 ft above sea level, in United States. The nearest listed city is Troutdale, 3.7 mi away.

Topography around Gresham

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

Within 2 miles, the terrain around Gresham has significant variations in elevation — a maximum elevation change of 906 ft around an average of 390 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,368 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 11,093 ft.

The land around Gresham is covered by trees (53%) and artificial surfaces (36%) within 2 miles, trees (56%) within 10 miles, and trees (79%) within 50 miles.

2 miles
906 ft
10 miles
1,368 ft
50 miles
11,093 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Troutdale 3.7 mi · Happy Valley 6.2 mi · Camas 6.2 mi · Lents 6.8 mi · Washougal 6.8 mi · Milwaukie 11 mi · Oak Grove 12 mi · Portland 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 Gresham (45.4982°, -122.4315°, elevation 318 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).