Fond du Lac weather in September

In September, Fond du Lac sees average daytime highs of 70°F and overnight lows near 53°F, with 2.9 in of rain across 9.2 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 75°F in the first days to 65°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 h 06 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Fond du Lac's 1st-clearest and 9th-windiest month. For the whole year in context, see Fond du Lac's year-round climate.

Daytime high
70°
4th warmest
Overnight low
53°
9th coldest
Rainfall
2.9 in
9.2 wet days
Daylight
12 h 18 min
5:39 AM – 5:57 PM
Cloud cover
53%
1st clearest
Wind
8 mph
9th windiest
Solar energy
4.18 kWh/m²
Travel score
6.7
out of 10

Fond du Lac is city in and county seat of Fond du Lac County, Wisconsin, United States.

Density
824/km²
people per km²
Founded
1843

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 65°F by the end.

A typical September day in Fond du Lac reaches about 70°F in the afternoon and slips back to 53°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 59°F and 81°F. Set against its neighbours, September runs about 7°F cooler than August and about 13°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17559
27558
37558
47558
57457
67457
77457
87356
97356
107356
117255
127255
137155
147154
157154
167053
177053
186953
196952
206952
216851
226851
236751
246750
256750
266649
276649
286548
296548
306448

How September really feels in Fond du Lac

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.

Fond du Lac weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan26° / 13°1.5879.10.0
Feb29° / 15°1.56.65.710.20.0
Mar40° / 25°2.394.611.60.4
Apr53° / 37°3.611.62.313.23.0
May65° / 48°3.611.30.114.55.7
Jun75° / 59°3.911.1015.26.6
Jul79° / 63°3.210.1014.96.7
Aug77° / 61°3.510.4013.86.9
Sep70° / 53°2.99.2012.36.7
Oct57° / 42°2.89.60.310.84.1
Nov43° / 30°2.08.12.49.50.7
Dec31° / 19°1.875.88.80.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15842
25941
35842
45842
55842
65842
75743
85644
95644
105545
115446
125347
135347
145248
155248
165248
175248
185248
195248
205149
215149
225149
235149
245149
255050
265050
275050
284951
295050
304951

Chance of precipitation in September

Any precipitation

Fond du Lac gets around 2.9 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 34% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
128
228
328
427
527
627
727
828
928
1029
1129
1230
1330
1431
1531
1632
1732
1832
1932
2033
2133
2233
2334
2434
2534
2634
2734
2834
2934
3034

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 59% of days. Sticky, muggy-or-worse air turns up on roughly 8% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1332523172
2352523162
3372422152
4392422142
5412321131
6432321121
7452320111
8462220101
9482219101
1050211991
1151211891
1253211781
1354211681
1457201670
1558201570
1659201470
1762191360
1863191260
1965181250
2067171150
2169161050
227116940
237315840
247414840
257713730
267812730
278011630
288011630
298210620
30849520

Wind in September

Winds average 8 mph in September.

Across September, daily wind ranges from about 8 mph on the calmest days to 9 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
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
179light breeze
189light breeze
199light breeze
209light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
279light breeze
289light breeze
299light breeze
309light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 min 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 90 minutes over September. Sunrise moves from 5:22 AM to 5:56 AM, and sunset from 6:25 PM to 5:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.15:226:25
213.05:236:23
313.05:246:22
412.95:256:20
512.95:266:18
612.85:286:16
712.85:296:14
812.75:306:12
912.75:316:10
1012.65:326:08
1112.65:336:07
1212.55:356:05
1312.55:366:03
1412.45:376:01
1512.35:385:59
1612.35:395:57
1712.25:405:55
1812.25:425:53
1912.15:435:51
2012.15:445:49
2112.05:455:47
2212.05:465:45
2311.95:475:44
2411.95:495:42
2511.85:505:40
2611.85:515:38
2711.75:525:36
2811.75:535:34
2911.65:555:32
3011.65:565:30

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.18 kWh/m².

For context, solar energy here swings from a low near 1.53 kWh/m² to a high of 6.27 kWh/m² in June across the year — September's 4.18 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.8Bright
34.7Bright
44.7Bright
54.6Bright
64.6Bright
74.5Bright
84.5Bright
94.4Bright
104.4Bright
114.3Bright
124.3Bright
134.2Bright
144.2Bright
154.2Bright
164.1Bright
174.1Bright
184.0Bright
194.0Moderate
204.0Moderate
213.9Moderate
223.9Moderate
233.8Moderate
243.8Moderate
253.8Moderate
263.7Moderate
273.7Moderate
283.6Moderate
293.6Moderate
303.6Moderate
Planning a trip in September

Is September a good time to visit Fond du Lac?

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

6.7
Sightseeing
2nd-best month of the year
4.2
Beach & pool
4th-best month of the year

September is a reasonable time to visit Fond du Lac for sightseeing.

What to pack for Fond du Lac in September

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

In September, Fond du Lac sees daytime highs around 70°F and nights near 53°F. Worth packing: rain gear. About 9 days see rain.

rain gear

Sea temperature near Fond du Lac in September

The nearest coast averages about 65°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 40 mi away) is warmest in August at about 70°F and coldest in March near 36°F.

It's comfortable for a long swim from Jul 31 to Aug 28 — about 1 month when the water holds above 68°F.

30°40°50°60°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarm
Sea temperature (°F)Comfort
Jan38Bracing
Feb36Bracing
Mar36Bracing
Apr38Bracing
May42Bracing
Jun54Bracing
Jul66Cool
Aug70Refreshing
Sep65Cool
Oct55Bracing
Nov46Bracing
Dec41Bracing

UV index in Fond du Lac 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 Fond du Lac peaks around June 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 18UV 9Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug7Very high
Sep6High
Oct3Moderate
Nov2Low
Dec1Low

Air quality in Fond du Lac 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 Fond du Lac is worst in July — around 15 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (November, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodJul 1415 µg/m³Nov 118 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb12Moderate
Mar13Moderate
Apr12Good
May13Moderate
Jun14Moderate
Jul15Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Fond du Lac?

Fond du Lac sits at 43.8°N, 88.4°W, 761 ft above sea level, in United States. The nearest listed city is Oshkosh, 18 mi away.

Topography around Fond du Lac

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

Within 2 miles, the terrain around Fond du Lac has only modest variations in elevation — a maximum elevation change of 118 ft around an average of 774 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 551 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 764 ft.

The land around Fond du Lac is covered by artificial surfaces (42%), trees (28%) and grassland (22%) within 2 miles, cropland (48%) within 10 miles, and cropland (42%) and trees (25%) within 50 miles.

2 miles
118 ft
10 miles
551 ft
50 miles
764 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Oshkosh 18 mi · West Bend 27 mi · Neenah 29 mi · Menasha 30 mi · Beaver Dam 30 mi · Appleton 34 mi · Kaukauna 35 mi · Sheboygan 36 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 Fond du Lac (43.775°, -88.4388°, elevation 761 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).