Allendale weather in September

In September, Allendale sees average daytime highs of 71°F and overnight lows near 57°F, with 3.3 in of rain across 10.1 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 75°F in the first days to 66°F by the end. The sky is clear or mostly clear about 37% 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 Allendale's 3rd-clearest and 9th-windiest month. For the whole year in context, see Allendale's year-round climate.

Daytime high
71°
4th warmest
Overnight low
57°
9th coldest
Rainfall
3.3 in
10.1 wet days
Daylight
12 h 18 min
6:29 AM – 6:47 PM
Cloud cover
52%
3rd clearest
Wind
9 mph
9th windiest
Solar energy
4.38 kWh/m²
Travel score
6.6
out of 10

Allendale is census designated place in Ottawa County, Michigan, United States.

Density
287/km²
people per km²

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 75°F in the first days to 66°F by the end.

A typical September day in Allendale reaches about 71°F in the afternoon and slips back to 57°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 79°F. Set against its neighbours, September runs about 6°F cooler than August and about 12°F warmer than October.

40°50°60°70°80°151015202530
Avg high (°F)Avg low (°F)
17562
27562
37561
47461
57461
67460
77460
87360
97359
107359
117259
127258
137258
147158
157157
167157
177057
187056
196956
206955
216955
226855
236854
246754
256753
266753
276653
286652
296552
306552

How September really feels in Allendale

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.

Allendale weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan31° / 21°2.611.7119.20.0
Feb32° / 20°2.08.46.910.20.0
Mar41° / 28°2.69.54.211.60.4
Apr52° / 38°4.1121.613.12.7
May64° / 49°4.311.7014.45.3
Jun74° / 61°3.610.9015.16.7
Jul78° / 66°3.910.7014.86.7
Aug77° / 64°3.810.3013.86.9
Sep71° / 57°3.310.1012.36.6
Oct58° / 46°3.8120.210.84.2
Nov46° / 36°3.111.63.29.51.1
Dec36° / 28°2.712.19.38.90.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 44%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16139
26139
36238
46238
56139
66139
76139
86040
95941
105842
115842
125743
135743
145644
155644
165644
175545
185446
195446
205446
215347
225347
235248
245248
255149
265149
275050
285050
295149
305149

Chance of precipitation in September

Any precipitation

Allendale gets around 3.3 in of rain over 10.1 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 34% and peaks near 40% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
130
230
330
430
530
630
730
830
931
1031
1132
1232
1332
1433
1533
1634
1734
1834
1935
2035
2136
2237
2337
2438
2539
2639
2739
2840
2940
3039

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 50% of days. Sticky, muggy-or-worse air turns up on roughly 12% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1272522196
2292522186
3302621175
4322621175
5332621164
6352621154
7362620143
8382620143
9392620132
10402520132
11422519122
12432519121
13442518111
14462518111
15472517101
1649241791
1751241690
1853231580
1954231580
2057221470
2158221370
2261211260
2362211160
2465201050
256620950
266919840
276919840
287118740
297317730
307417630

Wind in September

Winds average 9 mph in September.

Across September, daily wind ranges from about 8 mph on the calmest days to 10 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
129light breeze
139light breeze
149light breeze
159light breeze
169light breeze
179light breeze
189light breeze
199light breeze
209light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
279light breeze
2810light breeze
2910light breeze
3010light 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 6:13 AM to 6:46 AM, and sunset from 7:14 PM to 6:21 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.06:137:14
213.06:147:13
312.96:157:11
412.96:167:09
512.86:177:07
612.86:187:05
712.76:197:04
812.76:217:02
912.66:227:00
1012.66:236:58
1112.56:246:56
1212.56:256:54
1312.46:266:52
1412.46:276:51
1512.36:286:49
1612.36:296:47
1712.26:316:45
1812.26:326:43
1912.16:336:41
2012.16:346:39
2112.06:356:37
2212.06:366:36
2311.96:376:34
2411.96:396:32
2511.86:406:30
2611.86:416:28
2711.76:426:26
2811.76:436:24
2911.66:446:23
3011.66:466:21

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.38 kWh/m².

For context, solar energy here swings from a low near 1.27 kWh/m² to a high of 6.65 kWh/m² in June across the year — September's 4.38 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.0Bright
25.0Bright
35.0Bright
44.9Bright
54.9Bright
64.8Bright
74.8Bright
84.7Bright
94.7Bright
104.6Bright
114.6Bright
124.5Bright
134.5Bright
144.4Bright
154.4Bright
164.3Bright
174.3Bright
184.2Bright
194.2Bright
204.1Bright
214.1Bright
224.0Bright
234.0Bright
244.0Moderate
253.9Moderate
263.9Moderate
273.8Moderate
283.8Moderate
293.7Moderate
303.7Moderate
Planning a trip in September

Is September a good time to visit Allendale?

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

6.6
Sightseeing
4th-best month of the year
4.3
Beach & pool
4th-best month of the year

September is a reasonable time to visit Allendale for sightseeing.

What to pack for Allendale in September

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

In September, Allendale sees daytime highs around 71°F and nights near 57°F. Worth packing: rain gear. About 10 days see rain.

rain gear

Sea temperature near Allendale in September

The nearest coast averages about 67°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 22 mi away) is warmest in August at about 71°F and coldest in March near 36°F.

It's comfortable for a long swim from Jul 20 to Sep 8 — about 1.7 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan39Bracing
Feb37Bracing
Mar36Bracing
Apr38Bracing
May44Bracing
Jun56Bracing
Jul68Cool
Aug71Refreshing
Sep67Cool
Oct58Bracing
Nov49Bracing
Dec43Bracing

UV index in Allendale 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 Allendale peaks around June 21 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 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 highHighModerateLowJun 21UV 9Dec 21UV 1
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug7Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Allendale 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 Allendale is worst in June — around 16 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (November, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJun 2216 µg/m³Nov 137 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb10Good
Mar12Moderate
Apr13Moderate
May15Moderate
Jun16Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct7Good
Nov7Good
Dec7Good
Location & terrain

Where is Allendale?

Allendale sits at 43.0°N, 86.0°W, 653 ft above sea level, in United States. The nearest listed city is Jenison, 9.3 mi away.

Topography around Allendale

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

Within 2 miles, the terrain around Allendale has only modest variations in elevation — a maximum elevation change of 125 ft around an average of 650 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 279 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 692 ft.

The land around Allendale is covered by trees (34%), grassland (29%) and cropland (27%) within 2 miles, trees (38%), cropland (29%) and grassland (27%) within 10 miles, and trees (41%) and water (29%) within 50 miles.

2 miles
125 ft
10 miles
279 ft
50 miles
692 ft
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Jenison 9.3 mi · Walker 9.3 mi · Grandville 11 mi · Wyoming 13 mi · Grand Rapids 14 mi · Holland 15 mi · Kentwood 17 mi · Norton Shores 21 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 Allendale (42.9723°, -85.9536°, elevation 653 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).