Climate Insights for Lewiston

The climate in Lewiston is temperate. The average annual temperature is 15°C and approximately 1178mm of precipitation falls per year. January is the wettest month, receiving around 282mm of rainfall. Lewiston is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are December, February, January, when temperatures can drop to 2°C. Snowfall occurs from January to December, with around 136cm accumulating over the season.

Temperatures in Lewiston vary considerably across the year, with a 33°C difference between the coldest and warmest months. July is the hottest month, with daytime highs reaching 35°C and an average of 27°C. December is the coolest month, with minimum temperatures around 2°C and an average of 6°C. On average, daily temperatures fluctuate by about 13°C between overnight lows and afternoon highs. The sharpest temperature change occurs between September and October, with a 6°C shift in average temperatures.

Lewiston is a moderately rainy area, receiving approximately 1178mm of precipitation annually, which averages out to around 98mm per month. The wettest month is January, averaging 282mm of rainfall. March and February also tend to see above-average precipitation. The driest month is July, with just 1mm. That's 281mm less than January, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Snowfall is a regular feature from January to December, with around 136cm accumulating over the season. January typically sees the most snow at around 50cm.

Lewiston is relatively calm, with an average annual wind speed of 2km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 2km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 2km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 0km/h between the calmest and windiest months.

It is currently summer in Lewiston, which began on June 21, 2026. Lewiston 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 35°C, while the coldest stretch bottoms out in December near 2°C. Autumn is next, beginning on September 23, 2026 — 83 days from now.

The best time to visit Lewiston is during May, June, September and October, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 41mm per month. By contrast, July can be uncomfortably hot with highs reaching 35°C, while December is the coldest period with lows dropping to 2°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Lewiston 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.