Climate Insights for Oswego

The climate in Oswego is cool. The average annual temperature is 10°C and approximately 1416mm of precipitation falls per year. Oswego receives a notable amount of rainfall throughout the year, including during its driest month. Oswego is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, September. The coldest months are February, January, March, when temperatures can drop to -4°C. Oswego experiences heavy snowfall, typically from January through December.

Temperatures in Oswego vary considerably across the year, with a 29°C difference between the coldest and warmest months. July is the warmest month, though highs remain moderate at 25°C with a mean of 22°C. The coldest month is February, when overnight lows fall to -4°C and the daily average is -1°C. Daily temperature variation is modest, with an average difference of 5°C between highs and lows. The sharpest temperature change occurs between October and November, with a 7°C shift in average temperatures.

Oswego is a fairly wet location, receiving approximately 1416mm of precipitation annually, which averages out to around 118mm per month. The wettest month is October, averaging 157mm of rainfall. December and July also tend to see above-average precipitation. The driest month is September, with just 93mm. That's 65mm less than October, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around. Oswego receives heavy snowfall, accumulating around 221cm annually from January through December. The snowiest month is January, with approximately 60cm. Winter travel should account for significant snow cover.

Oswego is mildly breezy, with an average annual wind speed of 16km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is December, averaging 20km/h, though still comfortable for most outdoor activities. The calmest conditions occur in July, with average winds dropping to 11km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 9km/h gap between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 19km/h in winter, 16km/h in spring, 12km/h in summer, 16km/h in autumn.

It is currently summer in Oswego, which began on June 21, 2026. Oswego is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 25°C, while the coldest stretch bottoms out in February near -4°C. Autumn is next, beginning on September 23, 2026 (7 days from now).

The best time to visit Oswego is during June and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 18°C with modest rainfall averaging 94mm per month. By contrast, July can be uncomfortably hot with highs reaching 25°C, while February is the coldest period with lows dropping to -4°C. Despite being the best months overall, some rain is still likely. Pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Oswego based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.