Winters in Casper are harsh, with temperatures often plummeting below -20°C in January and February. Daytime temperatures gradually warm up as spring approaches, but March's average temperature of 0°C still indicates a chill in the air. By April and May, temperatures rise significantly, reaching averages of 5°C and 11°C respectively, marking the beginning of warmer months. Summer is mild to hot, with July and August averaging around 23°C and 20°C, but the heat can be intense during brief periods of warm weather. As fall sets in, temperatures gradually cool down again, with October's average temperature of 8°C providing a comfortable respite before winter returns.