Statistics show that the average low temperature in September is 46.6 degrees (F) for the state of Minnesota. However, yesterday's actual lows provided by LawrencevilleWeather.com show that some locations reached as low as 29 degrees in the far northern part of the state. This beats the average low temperature of 35 degrees (F) in October across the state.
So? Why should you care? In weather, many times forecasters can use the persistence method of forecasting to their advantage. For example, if it was unusually warm for a couple of days, a forecaster may use the persistence method and say that it will remain warm. If it has been very rainy the last several hours and the skies look dark, the forecaster may say it will continue raining.
If we use the persistence method here, averaged out over a long period of time, it is possible that this indicates that the Northern US may be cooler than normal for the rest of fall. Now, this method has a lot of caveats and is not really used now that we have computer models. However, the possibility is there that this is an indication from Mother Nature on what is to come as far as the rest of Fall goes.