The changing weather patterns are subject not only to many meteorological phenomena, but also the actions of countless pokemon from Hippopotas to the legendary Kyogre. More confusing still, the future as a whole is subject to billions of individuals who can alter it in countless tiny ways. And although some say gods and legends can foretell the future as easily as the past, it seems impossible that a mere evolution of Eevee could be capable of such perception.
And yet, unlike Xatu, consulted only in the narrow field of matters of state for Alph, an Espeon's fur grants them not only the power to predict the weather, but to foretell even the personal lives of people with surprising accuracy decades down the line. Indeed, so common is this belief that humans who can predict the future (or charlatans who claim this ability) are often called ESPers, a term which derives from Espeon.
An Espeon's future sight is a useful gift and a horrible curse. It is true that they can comfort some through knowledge of pleasant fates or improve their own life this way, and weather predictions make them prized among many. But it is also true that they must see in vivid detail the moment of their own deaths, and if they avoid one death a different one will surely show. Their ability to predict the weather is little better, for although rain and clear skies grow less perceptible as time goes on, an Espeon's fur shows them the moment billions of years away at which the Sun boils the oceans even more clearly than it does tomorrow's storms.
There are very few people who realize that Espeon fur is not lavender, but bright green, for rare is the Espeon who allows their fur to grow at all.