Climate and average weather in Oswego

In Oswego, the summers are warm, showery, and mostly clear and the winters are very cold, snowy, and mostly cloudy.

Best: early June to late September

Over the course of the year, the temperature in Oswego typically varies from 21°F to 75°F, and is rarely below 6°F or above 81°F. August is the hottest month of the year, while February is the coldest.

Based on the travel score, the best time of year to visit Oswego for warm-weather activities is from early June to late September.

Hottest
Aug
75°
Coldest
Feb
21°
Wettest
Oct
5.4 in
Driest
Feb
3.1 in
Rain / yr
50.9 in
166 wet days
Daylight
8.8–15.2 h
shortest–longest
Elevation
285 ft
43.5°N
Clearest
Jul
49% cloud

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.

Oswego weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around early June to late September.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Oswego, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 3.8 months, from June 6 to September 29, with daily high temperatures above 65°F. The hottest month of the year in Oswego is August, with an average high of 75°F and low of 66°F.

The cool season lasts 3.5 months, from December 9 to March 23, with daily high temperatures below 40°F. The coldest month of the year in Oswego is February, with an average low of 21°F and high of 32°F.

Days typically run about 10°F warmer than nights year-round.

20°40°60°80°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°F)Avg low (°F)
Jan3222
Feb3221
Mar3827
Apr4838
May5847
Jun6858
Jul7566
Aug7566
Sep6959
Oct5849
Nov4738
Dec3830

How hot and cold Oswego really feels

Feels-like highFeels-like lowactual air temp

The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.

On the coldest nights, wind chill pulls the feels-like down to about 8°F (around February 1), with roughly 156 freezing days a year (feels-like at or below 32°F) 61 of them bitterly cold — worst in February.

20°40°60°80°JanFebMarAprMayJunJulAugSepOctNovDec
Feels-like high (°F)Air high (°F)Feels-like low (°F)Air low (°F)
Jan32321122
Feb32321021
Mar38381827
Apr48483138
May58584447
Jun68685858
Jul75756666
Aug75756666
Sep69695959
Oct58584549
Nov47473138
Dec38382030

Average hourly temperature in Oswego

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on August afternoons, near 75°F, and coldest before dawn in February, near 21°F.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Oswego weather by month

Every month at a glance. Click a month for its detailed page.

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

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Oswego gets about 50.9 in of precipitation a year. On a typical day the chance of rain is very wet, but that rises and falls sharply with the seasons.

The wetter season lasts 4.3 months, from around Sep 30 to Feb 7, peaking in January at about 64% chance on a given day. The drier stretch runs the rest of the year, bottoming out around May 20.

October is the wettest month by volume, with 5.4 in over about 15 wet days; February is the driest, with 3.1 in. Some of the cold-season precipitation falls as snow.

0%10%20%30%40%50%60%70%80%JanFebMarAprMayJunJulAugSepOctNovDecwetterdrierwettermostly drysome rainoften wetvery wetJan 1 · 64%May 20 · 36%
Rain on a day (%)Rain days
Jan5618
Feb4512
Mar4112
Apr4213
May3711
Jun3912
Jul4012
Aug4113
Sep3912
Oct4915
Nov5316
Dec6219

Monthly rainfall

Over a full year, Oswego collects about 50.9 in of rain across 166 wet days — roughly 4.2 in in an average month.

It doesn’t fall evenly. October is the wettest month with 5.4 in, while February is the driest at just 3.1 in. The three wettest months alone bring about 29% of the year’s total, and some of the cold-season precipitation falls as snow.

01234567JanFebMarAprMayJunJulAugSepOctNovDec4.13.13.54.43.64.24.44.34.45.44.64.8
Rainfall (in)Rain daysSnow days
Jan4.11816
Feb3.11210
Mar3.5127
Apr4.4132
May3.6110
Jun4.2120
Jul4.4120
Aug4.3130
Sep4.4120
Oct5.4150
Nov4.6164
Dec4.81912

Snow in Oswego

Average snowy days through the year, the snow-season span, and estimated snowfall — for ski trips and the perennial 'will there be snow at Christmas?' question.

Oswego averages about 50 snowy days a year. Snow season runs roughly Oct 30 to Apr 28 — about 6 months.

January is snowiest, with roughly 15 days of snow and an estimated 26 in of snowfall. Over the year that adds up to an estimated 95 in of snow.

05101520JanFebMarAprMayJunJulAugSepOctNovDecsnow seasonsnow seasonJan 18
Snow daysSnowfall (in)
Jan1626
Feb1021
Mar714
Apr23
May00
Jun00
Jul00
Aug00
Sep00
Oct00
Nov49
Dec1223

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Oswego, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.

The clearer part of the year begins around March 19 and lasts for 6.9 months, ending around October 15. The clearest month is July, when the sky is clear, mostly clear, or partly cloudy 63% of the time on average.

The cloudier part of the year begins around October 16 and lasts for 5.1 months, ending around March 18. The cloudiest month is January, when it is overcast or mostly cloudy 90% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecJul 6 · 64%Jan 7 · 8%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan1090
Feb2278
Mar3664
Apr4258
May4654
Jun5545
Jul6337
Aug6238
Sep5545
Oct3961
Nov2674
Dec1387

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 11, brings about 15 h 12 min of light; the shortest, around January 1, only 8 h 48 min — a swing of roughly 6 h 24 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan9.17:424:49
Feb10.27:145:27
Mar11.66:276:05
Apr13.25:306:42
May14.54:477:17
Jun15.24:307:43
Jul14.94:447:40
Aug13.85:167:04
Sep12.35:526:09
Oct10.86:285:15
Nov9.57:084:35
Dec8.87:394:26

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Oswego averages about 8 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 1 and 14 days.

The sunnier stretch runs 6.7 months, from around Mar 19 to Oct 9. The sunniest month is August, with roughly 13 sunny days (mixed).

The greyest month is January, down near 1 sunny days — about 90% fewer than the August peak.

05101520JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedbrightAug 2614 daysJan 131 days
Sunny daysSky
Jan1Gloomy
Feb4Gloomy
Mar7Gloomy
Apr8Mixed
May10Mixed
Jun11Mixed
Jul13Mixed
Aug14Mixed
Sep11Mixed
Oct7Gloomy
Nov4Gloomy
Dec2Gloomy

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

In Oswego, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 3.6 months, from around June 10 to September 27. The muggiest month is July, when the air feels humid, muggy or worse about 75% of the time.

The most comfortable stretch runs from around September 28 to June 9, and April is the most comfortable month — the air is dry or comfortable 100% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecApr 25 · 100%Jul 26 · 19%oppressivemuggyhumiddrycomfortablecomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
Jan1000000
Feb1000000
Mar1000000
Apr1000000
May898200
Jun38302380
Jul51932349
Aug918313210
Sep392423122
Oct8610410
Nov1000000
Dec1000000

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Oswego is typically light breeze, near 10 mph, and varies moderately with the seasons.

The windier part of the year lasts 6.5 months, from around Oct 2 to Apr 16. The windiest month is January, averaging about 12 mph (light breeze).

The calmer part of the year runs from around Apr 17 to Oct 1, with August the calmest month at about 8 mph.

051015JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezebreezyJan 1 · 12 mphAug 4 · 7 mph
Wind speed (mph)Feels
Jan12light breeze
Feb11light breeze
Mar10light breeze
Apr10light breeze
May8light breeze
Jun8light breeze
Jul7calm
Aug8light breeze
Sep9light breeze
Oct10light breeze
Nov11light breeze
Dec12light breeze

Best time to visit Oswego

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Oswego throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around mid September, Oswego is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 64°F and 82°F. Based on this score, the best time of year to visit Oswego for general outdoor tourist activities is from early June to late September, with a peak score in the last week of August.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timetravel scoretemperaturecloudsprecipitationAug 27 · 6.9

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan0.0poor
Feb0.0poor
Mar0.1poor
Apr1.6poor
May4.1fair
Jun6.1good
Jul6.8good
Aug6.7good
Sep6.2good
Oct3.8fair
Nov1.3poor
Dec0.0poor

The beach/pool score favors clear, rainless days with daytime highs between 75°F and 93°F. Based on this score, the best time of year to visit Oswego for hot-weather activities is from late June to early September, with a peak score in the last week of July.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationJul 22 · 5.8

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for Oswego, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

For a warm-season trip around August (highs near 75°F), the essentials are light clothes, rain gear and sun protection. In the cold season around February (highs near 32°F), pack a warm layer, a heavy coat and rain gear.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In August, Oswego sees daytime highs around 75°F and nights near 66°F. Worth packing: light clothes, rain gear and sun protection. About 13 days see rain.

Sea temperature near Oswego

Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.

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 (midday) in Oswego by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

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

Average hourly UV index in Oswego

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in July the burn window is concentrated in the middle of the day: about 8 hours a day reach index 3 (protection recommended), and 4.5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan00
Feb00
Mar3.50
Apr5.50
May7.53.5
Jun84
Jul84.5
Aug6.50
Sep5.50
Oct10
Nov00
Dec00
Almanac & agriculture

Growing season

Chance of a frost-free dayTypical season (≥50%)

The growing season in Oswego typically lasts about 254 days, from around March 29 to December 7 — the span where a frost-free day is more likely than not. It is reliably frost-free from April 17 to November 9.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecgrowing seasonMar 2950%Apr 1790%Nov 990%Dec 750%
Frost-free chance (%)Frost nights
Jan1931
Feb1428
Mar3131
Apr8515
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct990
Nov8221
Dec4131

Growing degree days

Degree days (base 50°F)Frost-free shaded

Growing degree days tally heat above 50°F: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Oswego banks about 2,261 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.

05001,0001,5002,0002,500JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°F·days)
Jan0
Feb0
Mar0
Apr0
May84
Jun379
Jul630
Aug637
Sep424
Oct107
Nov0
Dec0

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Oswego receives about 3.9 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 1.2 and 6.5 kWh/m².

The brighter stretch of the year lasts 6.2 months, from around Mar 17 to Sep 21. The brightest month is June, averaging about 6.4 kWh/m² (intense).

The dimmest month is December, down near 1.2 kWh/m² — roughly 80% less than the June peak.

012345678JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseJun 296.5 kWhDec 201.2 kWh
Solar energy (kWh/m²)Level
Jan1.6Dim
Feb2.6Moderate
Mar3.9Moderate
Apr4.9Bright
May6.0Bright
Jun6.4Intense
Jul6.3Intense
Aug5.5Bright
Sep4.2Bright
Oct2.7Moderate
Nov1.7Dim
Dec1.2Dim

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
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).