Oswego weather in September

In September, Oswego sees average daytime highs of 69°F and overnight lows near 59°F, with 4.4 in of rain across 11.5 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 73°F in the first days to 65°F by the end. The sky is clear or mostly clear about 38% 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 Oswego's 3rd-clearest and 8th-windiest month. For the whole year in context, see Oswego's year-round climate.

Daytime high
69°
3rd warmest
Overnight low
59°
10th coldest
Rainfall
4.4 in
11.5 wet days
Daylight
12 h 18 min
5:52 AM – 6:09 PM
Cloud cover
53%
3rd clearest
Wind
9 mph
8th windiest
Solar energy
4.19 kWh/m²
Travel score
6.2
out of 10

Oswego is city in and county seat of Oswego County, New York, United States.

Density
612/km²
people per km²
Founded
1796

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 73°F in the first days to 65°F by the end.

A typical September day in Oswego reaches about 69°F in the afternoon and slips back to 59°F overnight — a 10°F spread between the day's warmth and the night's chill. On most days the high lands between 61°F and 77°F. Set against its neighbours, September runs about 6°F cooler than August and about 11°F warmer than October.

40°50°60°70°80°151015202530
Avg high (°F)Avg low (°F)
17364
27363
37363
47363
57263
67262
77262
87262
97161
107161
117161
127160
137060
147060
157059
166959
176959
186958
196858
206858
216857
226757
236756
246756
256656
266655
276555
286555
296554
306454

How September really feels in Oswego

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.

Oswego weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan32° / 22°4.117.715.69.10.0
Feb32° / 21°3.112.41010.20.0
Mar38° / 27°3.512.46.511.60.0
Apr48° / 38°4.412.82.113.21.6
May58° / 47°3.611.4014.54.2
Jun68° / 58°4.212015.26.1
Jul75° / 66°4.412.1014.96.8
Aug75° / 66°4.312.7013.86.8
Sep69° / 59°4.411.5012.36.2
Oct58° / 49°5.415.4010.83.8
Nov47° / 38°4.616.23.99.51.3
Dec38° / 30°4.818.911.88.80.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 45%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16040
26040
35941
45941
55941
65842
75842
85743
95743
105743
115644
125644
135644
145545
155545
165545
175446
185446
195446
205347
215347
225347
235248
245248
255248
265050
275050
284951
294852
304852

Chance of precipitation in September

Any precipitation

Oswego gets around 4.4 in of rain over 11.5 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 39% and peaks near 47% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
135
235
336
436
536
636
737
837
937
1038
1138
1238
1338
1438
1538
1638
1738
1838
1938
2039
2139
2240
2340
2441
2542
2643
2744
2845
2946
3047

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 39% of days. Sticky, muggy-or-worse air turns up on roughly 14% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1172232226
2182332216
3192331216
4212431205
5222430195
6232530185
7252529174
8262528164
9282528164
10292627153
11312626143
12322625143
13342624132
14352623132
15372623122
16392622112
17402621112
18422621101
19432520101
2045252091
2147241981
2249241981
2350241871
2453231761
2556231650
2656231650
2759221540
2860221440
2962221330
3064211230

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
289light 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 5:34 AM to 6:08 AM, and sunset from 6:37 PM to 5:43 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:346:37
213.05:366:35
312.95:376:33
412.95:386:32
512.85:396:30
612.85:406:28
712.75:416:26
812.75:426:24
912.65:446:22
1012.65:456:20
1112.55:466:19
1212.55:476:17
1312.45:486:15
1412.45:496:13
1512.35:506:11
1612.35:526:09
1712.25:536:07
1812.25:546:05
1912.15:556:03
2012.15:566:02
2112.05:576:00
2212.05:595:58
2311.96:005:56
2411.96:015:54
2511.86:025:52
2611.86:035:50
2711.76:045:48
2811.76:065:46
2911.66:075:45
3011.66:085:43

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.19 kWh/m².

For context, solar energy here swings from a low near 1.22 kWh/m² to a high of 6.36 kWh/m² in June across the year — September's 4.19 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.8Bright
34.8Bright
44.7Bright
54.7Bright
64.6Bright
74.6Bright
84.5Bright
94.5Bright
104.4Bright
114.4Bright
124.3Bright
134.3Bright
144.3Bright
154.2Bright
164.2Bright
174.1Bright
184.1Bright
194.0Bright
204.0Moderate
213.9Moderate
223.9Moderate
233.8Moderate
243.8Moderate
253.7Moderate
263.7Moderate
273.6Moderate
283.6Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Is September a good time to visit Oswego?

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

6.2
Sightseeing
3rd-best month of the year
3.6
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Oswego for sightseeing.

What to pack for Oswego in September

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

In September, Oswego sees daytime highs around 69°F and nights near 59°F. Worth packing: rain gear. About 12 days see rain.

rain gear

Sea temperature near Oswego 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 8 mi away) is warmest in August at about 72°F and coldest in March near 37°F.

It's comfortable for a long swim from Jul 15 to Sep 13 — about 2 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan40Bracing
Feb37Bracing
Mar37Bracing
Apr38Bracing
May43Bracing
Jun57Bracing
Jul69Refreshing
Aug72Refreshing
Sep68Cool
Oct58Bracing
Nov50Bracing
Dec44Bracing

UV index in Oswego 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 Oswego peaks around July 12 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 1 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 highHighModerateLowJul 12UV 8Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr5High
May7Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Oswego?

Oswego sits at 43.5°N, 76.5°W, 285 ft above sea level, in United States. The nearest listed city is Clay, 25 mi away.

Topography around Oswego

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

Within 2 miles, the terrain around Oswego has only modest variations in elevation — a maximum elevation change of 240 ft around an average of 305 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 354 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,801 ft.

The land around Oswego is covered by trees (39%) and water (30%) within 2 miles, water (47%) and trees (42%) within 10 miles, and trees (41%) and water (39%) within 50 miles.

2 miles
240 ft
10 miles
354 ft
50 miles
1,801 ft
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Clay 25 mi · Cicero 27 mi · Syracuse 34 mi · Auburn 36 mi · Watertown 47 mi · Prince Edward 53 mi · Kingston 53 mi · Rome 55 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 Oswego (43.4554°, -76.5105°, elevation 285 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).