Oswego, New York climate: Normal weather by month, frost dates and records
Oswego's normal year runs from 19°F January nights to 80°F July afternoons, with 43.1 inches of precipitation and 140 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.3°C, January lows of −7°C, July highs of 26°C, 1,096 mm of precipitation a year.
- NOAA stationOswego
- Station IDUSC00306314
- Location43.45°N 76.54°W
- Elevation324 ft (99 m)
- Population17,047
On October 23, the normal high in Oswego is 56°F and the normal low 43°F, and the chance of measurable rain or snow is 50%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Oswego.
- Jan 31° 19°
- Feb 33° 20°
- Mar 41° 27°
- Apr 53° 37°
- May 66° 48°
- Jun 75° 57°
- Jul 80° 63°
- Aug 79° 62°
- Sep 72° 55°
- Oct 59° 45°
- Nov 47° 35°
- Dec 37° 26°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Oswego each month?
July is the warmest month, with normal highs of 80°F; January the coldest, with normal lows of 19°F. The most precipitation falls in October (4.59 in), the least in February (2.85 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 31°F | 19°F | 25.0°F | 3.76 | 44.7 | 20 | <1 | 27 | 9 h 20 min |
| February | 33°F | 20°F | 26.7°F | 2.85 | 35.3 | 16 | <1 | 25 | 10 h 30 min |
| March | 41°F | 27°F | 34.2°F | 3.03 | 17.1 | 15 | <1 | 22 | 11 h 50 min |
| April | 53°F | 37°F | 45.3°F | 3.48 | 2.8 | 14 | <1 | 8 | 13 h 20 min |
| May | 66°F | 48°F | 56.8°F | 3.29 | 0.0 | 13 | <1 | <1 | 14 h 40 min |
| June | 75°F | 57°F | 66.1°F | 3.38 | 0.0 | 12 | 1 | <1 | 15 h 20 min |
| July | 80°F | 63°F | 71.5°F | 3.37 | 0.0 | 11 | 1 | <1 | 15 h 10 min |
| August | 79°F | 62°F | 70.4°F | 3.45 | 0.0 | 11 | 1 | <1 | 14 h |
| September | 72°F | 55°F | 63.4°F | 3.92 | 0.0 | 11 | <1 | <1 | 12 h 30 min |
| October | 59°F | 45°F | 52.1°F | 4.59 | 0.2 | 15 | <1 | 1 | 11 h 10 min |
| November | 47°F | 35°F | 41.4°F | 4.12 | 9.4 | 16 | <1 | 12 | 9 h 40 min |
| December | 37°F | 26°F | 31.3°F | 3.89 | 30.6 | 19 | <1 | 24 | 9 h |
| Year (annual) | 56°F | 41°F | 48.7°F | 43.13 | 140.1 | 172 | 3 | 119 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −7°C | −3.9°C | 96 mm | 114 cm |
| February | 1°C | −7°C | −2.9°C | 72 mm | 90 cm |
| March | 5°C | −3°C | 1.2°C | 77 mm | 43 cm |
| April | 12°C | 3°C | 7.4°C | 88 mm | 7 cm |
| May | 19°C | 9°C | 13.8°C | 84 mm | 0 cm |
| June | 24°C | 14°C | 18.9°C | 86 mm | 0 cm |
| July | 26°C | 17°C | 21.9°C | 86 mm | 0 cm |
| August | 26°C | 17°C | 21.3°C | 88 mm | 0 cm |
| September | 22°C | 13°C | 17.4°C | 100 mm | 0 cm |
| October | 15°C | 7°C | 11.2°C | 117 mm | 1 cm |
| November | 8°C | 2°C | 5.2°C | 105 mm | 24 cm |
| December | 3°C | −3°C | −0.4°C | 99 mm | 78 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00306314; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Oswego?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August has the fewest days with rain (11).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00306314.
When is the last frost in Oswego?
In Oswego, the last spring frost (32°F) comes after April 22 in half of years and after May 7 in one year in ten; the first autumn frost comes before October 29 in half of years and before October 9 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 221 year in 10 after May 7; 9 in 10 after April 9
- First autumn frost, half of years before
- October 291 year in 10 before October 9; 9 in 10 before November 11
NOAA puts the median frost-free season at 187 days, and the season without a hard freeze (28°F) at 214 days.
A hard freeze (28°F) comes after April 10 in half of springs and before November 10 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Oswego in zone 6a in ZIP code 13126, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Oswego's NOAA station is in zone 6b: the coldest night of a typical year reaches −5°F (28 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in New York · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00306314; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Oswego?
In a normal year in Oswego, 3 days a year reach 90°F, 119 nights fall to 32°F or colder and 172 days bring measurable precipitation.
- Days at 90°F or more
- 3a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 119a normal year
- Days that stay below freezing
- 49high of 32°F or less
- Days with 0.01 inch of precipitation
- 172a normal year
- Days with 1 inch of snow or more
- 36a normal year
The highest temperature in Oswego's official record (kept by the National Weather Service since 1926) is 97°F, on August 14, 2002; the lowest is −23°F, on December 29, 1933.
The wettest calendar year on that record is 2008, with 55.97 in; the snowiest season is 1971–72, with 251.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00306314; records: ACIS (NOAA Regional Climate Centers), NWS threaded record OSWN6thr. Records use complete months only; a month missing more than three days is left out.
How sunny is Oswego?
Over a year 69% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Oswego, 3.6 kWh per square metre a day. August is the sunniest month (78%) and December the cloudiest (47%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 51% | 1.3 |
| February | 54% | 2.0 |
| March | 62% | 3.3 |
| April | 66% | 4.5 |
| May | 71% | 5.5 |
| June | 74% | 5.9 |
| July | 78% | 6.0 |
| August | 78% | 5.3 |
| September | 76% | 4.2 |
| October | 63% | 2.5 |
| November | 58% | 1.6 |
| December | 47% | 1.0 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Oswego need?
A normal year in Oswego brings 6,499 heating degree days, 21% more than the median U.S. place (5,373), and 587 cooling degree days, 35% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,660 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,240 | 0 |
| February | 1,072 | 0 |
| March | 957 | 0 |
| April | 596 | 3 |
| May | 280 | 26 |
| June | 68 | 101 |
| July | 7 | 208 |
| August | 11 | 178 |
| September | 113 | 65 |
| October | 404 | 6 |
| November | 710 | 0 |
| December | 1,043 | 0 |
| Year (annual) | 6,499 | 587 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00306314. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Oswego been warmer than normal lately?
2025 averaged 50.0°F, 1.3°F above the 1991-2020 normal of 48.7°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 52.0°F | +3.3°F | 42.26 | 63.4 |
| 2022 | 50.7°F | +2.0°F | 42.21 | 80.3 |
| 2023 | 51.6°F | +2.9°F | 42.77 | 35.4 |
| 2024 | 52.9°F | +4.1°F | 40.99 | 49.6 |
| 2025 | 50.0°F | +1.3°F | 36.07 | 117.7 |
Over 145 complete years from 1871 to 2025, the station's annual mean temperature rose at a fitted 2.6°F per century (+0.14°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00306314; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Oswego's climate compare?
Oswego is warmer than 87 of the other 130 places with their own NOAA record in New York, and wetter than 61. Across the 7,247 U.S. stations with normals, its annual mean of 48.7°F is warmer than 35%.
In the Köppen classification computed from these normals, Oswego is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Oswego share this climate record?
5 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- SUNY Oswego, NY3,565 people · 0 mi NW
- Minetto, NY1,433 people · 4 mi SE
- Fair Haven, NY771 people · 12 mi SW
- Hannibal, NY538 people · 9 mi S
- Red Creek, NY487 people · 17 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Oswego's climate
What is the coldest month in Oswego?
January, with a normal high of 31°F and a normal low of 19°F. The warmest is July (80°F by day, 63°F at night).
Does it snow in Oswego?
Yes: 140 inches in a normal year, falling on 62 days with 0.1 inch or more, the most in January (44.7 inches).
What is the rainiest month in Oswego?
October, with 4.59 in of precipitation in a normal year; the driest is February with 2.85 in.
What plant hardiness zone is Oswego in?
The USDA's 2023 map puts Oswego in zone 6a in ZIP code 13126, the nearest ZIP area. By the same method at Oswego's NOAA station, the coldest night of a typical year reaches −5°F (28 years, 1991-2020): zone 6b.
How late can frost come in Oswego?
In half of years the last 32°F night comes after April 22; in one year in ten it comes after May 7. Waiting until May 7 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Oswego in OctoberThis month day by day, its records and recent years
- New York climateThe statewide normals and every place in the state
- Fulton, NY11 miles from this station, 47.3°F a year
- Brewerton, NY22 miles from this station, 46.4°F a year
- Pulaski, NY22 miles from this station, 44.6°F a year
- Sodus, NY31 miles from this station, 46.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made