Norristown receives its highest rainfall in Jul, while humidity peaks during winter months.
🌧️ Wettest:Jul — 121 mm☀️ Driest:Feb — 72 mm
💧 Humidity peaks at 86% in Jan · annual avg 78%
🌍 Climate Summary
Avg Annual Temp:54°F
Avg Annual Rainfall:1177 mm
Avg Humidity:78%
Data Period:1981 – 2025
Norristown Climate Overview
Norristown has a warm temperate climate with warm summers and freezing winters.
Temperatures peak in Jul and drop to their lowest in Jan,
while rainfall is highest during summer months.
Humidity remains high throughout the year, especially during winter months, creating cold and damp conditions.
📈 Yearly Trends
The warmest year in Norristown's recorded history was 2024
(avg: 58.1°F),
while the coldest year was 1984
(avg: 50.2°F),
based on annual average temperatures.
📊 Key Climate Trends
🌡️ Norristown's temperature shows a slight warming trend over the past decade
📈 Minimum temperatures show a slight warming trend in recent years
🌧️ Rainfall has decreased in recent years compared to earlier periods
🌡️ Annual Temperature Trend
View Range:
Average annual high/low · Last 10 years · °F
Norristown's temperatures shows a slight warming trend over the past decade.
The highest recorded temperature reached
104.7°F in Jul 2019,
while the lowest dropped to
-16.5°F in Jan 1994.
🌧️ Annual Precipitation
View Range:
Total annual precipitation · Last 10 years · mm/year
Annual rainfall in Norristown shows noticeable variation. Rainfall has decreased in recent years compared to earlier periods.
Based on 45 years of data (1981–2025), Jul is typically the hottest month in Norristown, Pennsylvania, with average high temperatures around 96°F.
What is the coldest month in Norristown?▼
Jan is the coldest month in Norristown, with average low temperatures around 5.2°F.
What is the rainiest month in Norristown?▼
Jul receives the most rainfall with approximately 121 mm, while Feb is the driest with 72 mm.
What was the highest temperature ever recorded in Norristown?▼
The highest recorded temperature was 104.7°F in Jul 2019. This is part of the historical record spanning 1981–2025.
What was the lowest temperature ever recorded in Norristown?▼
The lowest recorded temperature was -16.5°F in Jan 1994.
How many years of data does this page cover?▼
This page covers 45 years of climate data from 1981 to 2025. As new data is added to the database the page automatically reflects the updated coverage.
How much sunlight does Norristown get?▼
Norristown receives the most sunlight in Jun with an average solar radiation of 5.88 kWh/m²/day. This solar radiation data, sourced from NASA POWER, is useful for solar energy planning, agriculture, and understanding seasonal sunshine availability in Pennsylvania.
Where does this weather data come from?▼
All climate data is sourced from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite and model data. It provides monthly averages for temperature, precipitation, humidity, wind speed, and solar radiation.
📚 Data Source
All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources), a NASA project providing solar and meteorological data for renewable energy, building efficiency, and agricultural research.