Valparaiso weather in September

In September, Valparaiso sees average daytime highs of 74°F and overnight lows near 57°F, with 3.2 in of rain across 9.1 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 78°F in the first days to 69°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 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Valparaiso's 1st-clearest and 9th-windiest month. For the whole year in context, see Valparaiso's year-round climate.

Daytime high
74°
4th warmest
Overnight low
57°
9th coldest
Rainfall
3.2 in
9.1 wet days
Daylight
12 h 18 min
5:34 AM – 5:51 PM
Cloud cover
50%
1st clearest
Wind
8 mph
9th windiest
Solar energy
4.57 kWh/m²
Travel score
7.0
out of 10

Valparaiso is city in Porter County, Indiana, United States.

Density
809/km²
people per km²
Founded
1836

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 69°F by the end.

A typical September day in Valparaiso reaches about 74°F in the afternoon and slips back to 57°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 64°F and 84°F. Set against its neighbours, September runs about 6°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17962
27862
37862
47861
57861
67861
77760
87760
97760
107659
117659
127658
137558
147558
157557
167457
177456
187456
197356
207355
217255
227255
237254
247154
257153
267053
277053
286952
296952
306951

How September really feels in Valparaiso

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.

Valparaiso 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
Jan32° / 20°2.710.47.29.30.0
Feb35° / 22°2.185.310.30.0
Mar46° / 30°3.010.53.411.71.1
Apr58° / 41°4.212.41.113.13.9
May68° / 52°4.512.9014.35.9
Jun78° / 62°4.111.9014.96.3
Jul82° / 66°3.911.9014.76.2
Aug80° / 64°3.911.1013.76.5
Sep74° / 57°3.29.1012.37.0
Oct62° / 46°3.3100.210.95.2
Nov48° / 35°2.99.61.79.71.8
Dec37° / 26°2.49.34.99.10.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 41% of the time in September, the clearest month of the year.

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 (%)
15941
25941
35941
45941
55941
66040
75941
85941
95941
105842
115941
125842
135743
145743
155743
165743
175644
185644
195644
205545
215446
225446
235446
245347
255347
265347
275248
285248
295248
305248

Chance of precipitation in September

Any precipitation

Valparaiso gets around 3.2 in of rain over 9.1 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 31% and peaks near 32% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
131
231
331
431
531
632
732
832
932
1032
1132
1232
1332
1432
1532
1631
1731
1831
1931
2031
2130
2230
2330
2430
2531
2631
2731
2831
2931
3031

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 46% of days. Sticky, muggy-or-worse air turns up on roughly 13% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1192524238
2202624227
3222723217
4242723206
5252723195
6272823185
7292822174
8312722154
9332722143
10352722143
11372622132
12392621122
13412521112
14432520111
15462419101
1648231991
1750231891
1852221781
1954221680
2057211570
2159211370
2261201270
2362201260
2464191160
2565191060
2667181050
276818950
286917950
297116940
307216840

Wind in September

Winds average 8 mph in September.

Across September, daily wind ranges from about 7 mph on the calmest days to 9 mph at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57light breeze
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
259light breeze
269light breeze
279light breeze
289light breeze
299light breeze
309light 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 5:19 AM to 5:49 AM, and sunset from 6:17 PM to 5:26 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:196:17
212.95:206:15
312.95:216:14
412.85:226:12
512.85:236:10
612.75:246:09
712.75:256:07
812.75:266:05
912.65:276:03
1012.65:286:01
1112.55:296:00
1212.55:305:58
1312.45:315:56
1412.45:325:54
1512.35:335:53
1612.35:345:51
1712.25:355:49
1812.25:365:47
1912.15:385:45
2012.15:395:44
2112.05:405:42
2212.05:415:40
2311.95:425:38
2411.95:435:36
2511.85:445:35
2611.85:455:33
2711.85:465:31
2811.75:475:29
2911.75:485:28
3011.65:495:26

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.57 kWh/m².

For context, solar energy here swings from a low near 1.58 kWh/m² to a high of 6.55 kWh/m² in June across the year — September's 4.57 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.2Bright
25.1Bright
35.1Bright
45.0Bright
55.0Bright
65.0Bright
74.9Bright
84.9Bright
94.8Bright
104.8Bright
114.8Bright
124.7Bright
134.7Bright
144.6Bright
154.6Bright
164.5Bright
174.5Bright
184.5Bright
194.4Bright
204.4Bright
214.3Bright
224.3Bright
234.2Bright
244.2Bright
254.1Bright
264.1Bright
274.0Bright
284.0Bright
294.0Moderate
303.9Moderate
Planning a trip in September

Is September a good time to visit Valparaiso?

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

7.0
Sightseeing
1st-best month of the year
5.5
Beach & pool
4th-best month of the year

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

What to pack for Valparaiso in September

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

In September, Valparaiso sees daytime highs around 74°F and nights near 57°F. Worth packing: light clothes, rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

Sea temperature near Valparaiso in September

The nearest coast averages about 68°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 19 mi away) is warmest in August at about 73°F and coldest in February near 35°F.

It's comfortable for a long swim from Jul 10 to Sep 16 — about 2.3 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb35Bracing
Mar35Bracing
Apr39Bracing
May46Bracing
Jun59Cool
Jul70Refreshing
Aug73Refreshing
Sep68Refreshing
Oct58Bracing
Nov49Bracing
Dec42Bracing

UV index in Valparaiso 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 Valparaiso peaks around June 21 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 2 (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 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Valparaiso 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 Valparaiso is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1516 µg/m³Oct 228 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar14Moderate
Apr13Moderate
May15Moderate
Jun15Moderate
Jul17Moderate
Aug15Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Valparaiso?

Valparaiso sits at 41.5°N, 87.1°W, 794 ft above sea level, in United States. The nearest listed city is Portage, 9.3 mi away.

Topography around Valparaiso

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

Within 2 miles, the terrain around Valparaiso has only modest variations in elevation — a maximum elevation change of 217 ft around an average of 774 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 315 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 689 ft.

The land around Valparaiso is covered by trees (46%), artificial surfaces (28%) and grassland (22%) within 2 miles, cropland (46%) and trees (30%) within 10 miles, and cropland (45%) and water (22%) within 50 miles.

2 miles
217 ft
10 miles
315 ft
50 miles
689 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Portage 9.3 mi · Hobart 11 mi · Merrillville 14 mi · Crown Point 16 mi · Gary 17 mi · Michigan City 18 mi · Griffith 19 mi · La Porte 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 Valparaiso (41.4731°, -87.0611°, elevation 794 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).