Oswego climate — normals and trends
Oswego (United States) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 8.6 °C and it receives 1,294 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is August (21.2 °C on average) and the coldest is February (-3.8 °C). Rainfall peaks in November.
Oswego averages 101 frost days, 0 hot days (≥ 30 °C) and 170 rainy days per year.
Oswego has warmed by +1.5 °C between 1940 and 2025, or +0.18 °C per decade. This trend is statistically significant.
The number of frost days there went from about 114 to 88 per year over the period.
The hottest day of the period reached 31.9 °C (on 3 August 1988) and the coldest -24.6 °C (on 18 February 1979).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
OswegoNew York
- coords
- 43.46°, -76.51°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
8.6°C
Average daily high
11.5°C
Average daily low
5.9°C
Annual rainfall
1,294mm
Sunshine / day
8.6h
Mean relative humidity
78%
Average peak wind
22.3km/h
Seasonal range
25.0°C
Frost days (< 0 °C)
101 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
170 d/yr
Annual snowfall
160.2 cm
Average feels-like high
9.4 °C
Average feels-like low
2.5 °C
Average peak gust
40.3 km/h
Tropical nights (≥ 20 °C)
22 d/yr
Solar radiation
14.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.5 °C
since 1940
+0.2 °C per decade · r² = 0.28 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
31.9 °C
3 August 1988
Coldest day
-24.6 °C
18 February 1979
Wettest day
86 mm
31 August 2005
Windiest day
64.0 km/h
6 April 1979
Strongest gust
122.4 km/h
25 February 2019
Hottest feels-like
38.7 °C
3 August 1988
Coldest feels-like
-30.6 °C
4 January 1981
Snowiest day
33.5 cm
25 December 1978
Sunniest day
14.9 h
19 June 2022
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -0.5 °C | -0.1 °C | 117 mm | +13 mm |
| Feb | -0.6 °C | +0.1 °C | 115 mm | +33 mm |
| Mar | 6.6 °C | +3.7 °C | 74 mm | -18 mm |
| Apr | 9.5 °C | +1.0 °C | 121 mm | +15 mm |
| May | 13.5 °C | -0.6 °C | 151 mm | +52 mm |
| Jun | 20.4 °C | +0.7 °C | 90 mm | -10 mm |
| Jul | 25.3 °C | +1.5 °C | 60 mm | -44 mm |
| Aug | 24.0 °C | +0.1 °C | 89 mm | -25 mm |
| Sep | 21.5 °C | +1.0 °C | 42 mm | -75 mm |
| Oct | 15.9 °C | +1.3 °C | 151 mm | +26 mm |
| Nov | 7.5 °C | -0.9 °C | 138 mm | +10 mm |
| Dec | 2.1 °C | -0.8 °C | 147 mm | +23 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Oswego?
Oswego has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 8.6 °C and it receives 1,294 mm of precipitation per year.
What is the hottest day ever recorded in Oswego?
The hottest day measured in Oswego between 1940 and 2025 was 3 August 1988, reaching 31.9 °C.
What is the coldest day in Oswego?
The coldest day measured in Oswego between 1940 and 2025 was 18 February 1979, at -24.6 °C.
Does it snow in Oswego?
Yes. Oswego gets on average 160.2 cm of snow per year and has around 101 frost days.
Has the climate of Oswego warmed?
Yes: Oswego warmed by +1.5 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Oswego?
The wettest day measured in Oswego between 1940 and 2025 was 31 August 2005, with 86 mm of rain in 24 hours.
What was the windiest day in Oswego?
The windiest day measured in Oswego between 1940 and 2025 was 6 April 1979, with winds reaching 64.0 km/h.
What is the warmest month in Oswego?
The warmest month in Oswego is August (21.2 °C on average); the coldest is February (-3.8 °C).
How much does it rain in Oswego?
Oswego receives on average 1,294 mm of precipitation per year, spread over about 170 rainy days.
Is it sunny in Oswego?
Oswego gets on average 8.6 hours of sunshine per day, roughly 3,139 hours per year over 1940-2025.
What is the biggest single-day snowfall in Oswego?
The heaviest 24-hour snowfall measured in Oswego between 1940 and 2025 was 25 December 1978, with 33.5 cm.
Are there tropical nights in Oswego?
Yes: Oswego has on average 22 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Oswego?
In Oswego, between 1940 and 2025, the highest apparent temperature reached 38.7 °C on 3 August 1988, and the lowest was -30.6 °C on 4 January 1981.
Compare Oswego with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Oswego