<P> Autumn weather in Minnesota is marked by the rapid decrease of severe thunderstorms , dramatic cooling , and eventually the possibility of blizzards . With summer - time heat still prevalent in the southern U.S. and colder air quickly taking hold in Canada , Minnesota can be affected by wide temperature swings in short periods of time . Because of this , the jet stream , which tends to weaken during the summer months , begins to re-strengthen . This leads to quicker changes in weather patterns and increasingly strong storm systems . As autumn moves on , these storm systems bring with them progressively colder air , eventually changing the rain over snow , generally starting in October in the northern part of the state and November in the south . From September to December the average temperature in the state falls by approximately 43 ° F ( 23 ° C ) , the largest such temperature swing within any Minnesota season . </P>
<P> Autumn weather in Minnesota is marked by the rapid decrease of severe thunderstorms , dramatic cooling , and eventually the possibility of blizzards . With summer - time heat still prevalent in the southern U.S. and colder air quickly taking hold in Canada , Minnesota can be affected by wide temperature swings in short periods of time . Because of this , the jet stream , which tends to weaken during the summer months , begins to re-strengthen . This leads to quicker changes in weather patterns and increasingly strong storm systems . As autumn moves on , these storm systems bring with them progressively colder air , eventually changing the rain over snow , generally starting in October in the northern part of the state and November in the south . From September to December the average temperature in the state falls by approximately 43 ° F ( 23 ° C ) , the largest such temperature swing within any Minnesota season . </P>
when does it start cooling down in minnesota
when does it start cooling down in minnesota
September
September