Because weather is often unpredictable and directly affects the conditions following it, 10-day weather forecasts may or may not be accurate. Short-range forecast predictions, defined as those up to 48 or 72 hours from the present, are generally much more accurate than those of longer periods.
Ten-day weather forecasts tend to be most accurate when weather conditions remain relatively stable. Forecasts during periods of extreme weather, such as a severe storm, are often unreliable. According to the Time And Date AS website, while weather is constantly changing and predictions are always subject to error, observation techniques have improved to the point where five-day forecasts of today are as reliable as two-day forecasts of years ago.