On March 1, 1872, Yellowstone became the first national park, created for all to enjoy its unique hydrothermal wonders. Today, millions of people come each year to camp, hike, and enjoy the park's majesty. Yellowstone's weather can vary greatly, even in a single day. In summer, daytime highs can exceed 70°F (25°C), then drop 20 or more degrees when a thunderstorm rolls through. Snow can fall during any month of the year, and winter lows frequently drop below 0°F (-18°C), especially at night.