Philadelphia's winters are quite chilly, with temperatures often below freezing and averaging around 1-5°C. Spring brings a gradual warming trend, with March and April seeing significant increases in temperature, reaching up to 28-31°C on occasion. Summer is warm and relatively stable, with July and August being the hottest months, but still not excessively hot, topping out at 35°C. Autumn sees a return to cooler temperatures, with September being the mildest month before the chill of winter sets back in. Overall, Philadelphia's temperature fluctuations are moderate, with no extreme heat or cold spells throughout the year.