Climate Insights for Norristown

The climate in Norristown is temperate. The average annual temperature is 13°C and approximately 1000mm of precipitation falls per year. Norristown receives a notable amount of rainfall throughout the year, including during its driest month. Norristown 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 January, February, December, when temperatures can drop to -4°C. Snowfall occurs from January to December, with around 93cm accumulating over the season.

Temperatures in Norristown vary considerably across the year, with a 35°C difference between the coldest and warmest months. The warmest month is July, when average highs reach 31°C and the mean temperature sits around 26°C. The coldest month is January, when overnight lows fall to -4°C and the daily average is 0°C. On average, daily temperatures fluctuate by about 9°C between overnight lows and afternoon highs. The sharpest temperature change occurs between September and October, with a 7°C shift in average temperatures.

Norristown is a moderately rainy area, receiving approximately 1000mm of precipitation annually, which averages out to around 83mm per month. The wettest month is July, averaging 127mm of rainfall. May and September also tend to see above-average precipitation. The driest month is March, with just 43mm. That's 84mm less than July, the wettest month. Precipitation varies noticeably between seasons, with the second half (July to December) of the year generally seeing more rainfall. Snowfall is a regular feature from January to December, with around 93cm accumulating over the season. January typically sees the most snow at around 55cm.

Norristown is relatively calm, with an average annual wind speed of 3km/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 4km/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. There is moderate seasonal variation in wind speed, with a 2km/h gap between the calmest and windiest months.

It is currently summer in Norristown, which began on June 21, 2026. Norristown 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 31°C, while the coldest stretch bottoms out in January near -4°C. Autumn is next, beginning on September 23, 2026 — 52 days from now.

The best time to visit Norristown is during June, when the weather is most comfortable for travellers. During these months, average temperatures hover around 22°C with modest rainfall averaging 76mm per month. By contrast, July can be uncomfortably hot with highs reaching 31°C, while January 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 Norristown 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.