(Photo by Dave Clark)
Extremes of weather and climate prevail at Craters of the Moon across seasons and elevations. From the foothills of the Pioneer Mountains on the northern end of the monument to the Snake River on the south, weather conditions vary significantly. As elevation decreases from north to south, temperatures increase and precipitation decreases. Average annual precipitation ranges from 16 inches at the monument Visitor Center to just under 10 inches near the Snake River at Minidoka Dam. In February, average snow depth ranges from 26 inches at the north end of the monument to just 2 inches at the south end. Intense summer sun bakes the black lava, generating surface temperatures of 170 degrees Fahrenheit and air temperatures in the 90s. Drying winds are a daily occurence, especially in the afternoon, and may reach 15 to 30 miles per hour. In June, July, and August, the average monthly precipitation is less than two inches. Winter transforms Craters of the Moon into a dramatic landscape of rugged black lava and soft white snow. Fall and spring are milder, with unsettled weather. Despite harsh conditions, delicate wildflowers burst to life in May or June against the more monochromatic background of the cinder slopes: pink monkeyflowers, yellow dwarf buckwheats, white bitterroots, and many others. No matter what the season or the weather, the wide open desert sky at Craters of the Moon offers unobstructed views of spectacular cloud formations, sunrises, sunsets, moonscapes, and stars.