Norristown experiences a relatively mild climate, with temperatures gradually warming up throughout the year. Winters are chilly, with January and February averaging around freezing point, but with occasional drops below -15°C. As spring arrives in March, temperatures rise significantly, often reaching highs of over 28°C, while summers are warm, with July and August averaging around 24°C. Autumn brings a slight cooling trend, with September experiencing a bit of a temperature drop before October's mild temperatures return to similar levels as May. Winter temperatures remain cool, but not extreme, in December.