Image of the Day for May 12, 2026 Valley fog gathered in the Victorian Alps while an arch-shaped cloud drifted across Port Phillip Bay. May 12, 2026 View more Images of the Day: It’s autumn in the Southern Hemisphere, which means it's fog season in the Victorian Alps . NASA's Terra satellite captured this view of morning fog filling valleys in several national parks across the mountains of eastern Victoria in May.   As nights lengthen with the season, the atmosphere has more time to cool and approach the dew point —the temperature at which the air becomes saturated and water vapor can condense into radiation fog . Because cold air is denser than warm air, it sinks and drains into valleys, allowing fog to develop there first. In low-elevation areas, radiation fog usually fades as the Sun warms the ground, but it tends to linger in mountain valleys because they remain shaded longer. On this day, geostationary satellite imagery shows the fog persisting for about two hours.…