Eilämpövaikutuksen

Eilämpövaikutuksen, meaning "yesterday's heat effect" in Finnish, refers to a meteorological phenomenon where the thermal inertia of the ground or large bodies of water influences the temperature of the following day, particularly during transitional seasons like spring or autumn. This effect is most noticeable when there is a significant temperature difference between consecutive days.

For instance, if a region experiences a prolonged period of warm weather, the ground or water will absorb and store a substantial amount of heat. When a cold front arrives, the ground or water will continue to release this stored heat, moderating the immediate drop in air temperature. Conversely, after a cold spell, the ground may retain coldness, and if a warm air mass moves in, the surface temperature might rise more slowly than the air temperature due to this "yesterday's cold" effect.

The magnitude of eilämpövaikutuksen depends on several factors, including the type of surface (e.g., soil, sand, rock, water), its moisture content, and the duration of the preceding temperature anomaly. Bodies of water, due to their high specific heat capacity, exhibit a stronger thermal inertia and thus a more pronounced eilämpövaikutuksen compared to land surfaces. This phenomenon plays a role in local weather patterns and can influence the timing and intensity of temperature changes.