14 Day Odds and Forecast Confidence
Southampton • from 51 runs of the European ensemble forecast
A normal forecast gives one answer. An ensemble runs the same forecast dozens of times with tiny changes to the starting conditions. If nearly all the runs agree, you can be confident. If they spread out, the weather is hard to call. The table below shows the chance of rain, of heavy rain, of frost and of snow for each day, and the graphs show how wide the spread is.
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How to Read This
The shaded band on each graph covers the middle half of the runs; the line is the median. A narrow band means a confident forecast, and a band that fans out after a few days is normal, because every forecast loses accuracy the further ahead it looks. “Heavy rain” means 5 mm or more in a day, “frost” means a low of 0°C or below, and “snow” means measurable snowfall at our location. Chances are the share of the 51 runs that show the event; they are guidance, not a promise.
See also 5 Day Forecast, Snow Probability Tracker and Weather Model Maps.