August is a hot and humid summer month in Pennsylvania with a combination of sunny and cloudy days. Sunshine spans for nearly 20 days during the month, and midday temperatures are the hottest. The average high temperatures are in the hot range of 77°F (25°C) to 87°F (30.6°C), while the average low temperatures are 53°F (11.7°C) to 68°F (20°C). Norristown in the southeastern corner of the state averages between 64°F (17.8°C) to 87°F (30.6°C), Lancaster in the south is between 63°F (17.2°C) to 84°F (28.9°C), while Altoona in the west ranges between 58°F (14.4°C) to 80°F (26.7°C). August has plenty of rainfall and prone to thunderstorms or odd cyclones. Summer days provide a barrage of activities to the swelling crowds - it is the perfect time to enjoy the coolness of the water in the scorching sun. Light sweatshirts are suitable to wear in the sun - note that the ultraviolet index of the sun is in the highest range in August, so take adequate protection, while venturing out in the heat.