Despite rainfall being above average in central Minnesota, it s slowed its pace just a bit for the second straight month. 2014年9月 rainfall at the St. 云 Regional Airport totalled 4.06英寸，0.比平均值高60英寸. Still, the pace of rainfall is among the five highest. For the growing season (since April 1), the total is 29.72英寸，9英寸.47 inches above average and the 4月至9月第五潮湿 历史上. For the calendar year through September, St. 云收到了33个.43 inches of precipitation, 10.比平均水平高39英寸. 这是St。. 云的 fourth wettest January through September 在122年的记录中.

Nearly three-quarters (72%) of the September rain fell during the morning and midday of 9月3日. A relatively narrow rainband developed between the Twin Cities and 穿过街道. Augusta and the southern portion of St. 云. 圣. 云机场获得2分.94英寸 of rain from this storm, nearly double the old 9月3日 record of 1.61英寸，设定于2006年. 2.70 inches fell in just one hour. 这也是圣. 云机场 largest single storm rainfall 自2005年10月4日至5日.7英寸).

With additional rainfall to begin October, the St. 云 precipitation through October 2 now stands at 33.71英寸. If this was the final rainfall total for the year, it would be the 16th wettest year 历史上 at 5.比平均水平高98英寸.

的 rainy conditions also helped to contribute to a "wait-a-minute" temperature month. 那里有剧烈的摇摆 between chilly days (3 straight days more than 10 degrees cooler than average) and very warm days (6 days at least 10 degrees above average, 包括连续5天). 的 month ended up averaging 61.9°F, 2.比正常高6华氏度. 的 persistently humid conditions, especially early and late in the month, contributed to the average low temperature being 50.4°F, 3.比正常高6华氏度. This was the 20th warmest September average low 历史上. In contrast, the September high temperature averaged 72.0°F, 1.比正常高9华氏度. This continues the trend of warm lows seen through much of the summer.

的 largest contrast was between the 4 straight days with a high of at least 80°F September 25-28 and the three straight days with a high in the 50's September 10-12. 的 late September warm period marked the longest streak of 80+ highs later than September 15 since 2011. That 4-day 80+ streak occurred on October 3-7. 的 last time there were 4 straight days actually in the second half of September was September 16-19 or 1998.

的 three straight cold days earlier in the month made the first streak of sub-60 highs in the first half of September since 1986 (9月13日-15). 的 last time there was any streak of three straight sub-60 degree highs was September 14-16, 2011(是的, that was just three weeks before 5 straight 80-degree days in October that year).

这是公平的 widespread frost in central Minnesota on 9月13日, including in many parts of the city. 然而，圣。. 云 Airport never got colder than 33 degrees that morning. If the Airport had dropped another degree, this frost would have been ranked among the earliest 10% of first frosts. However, there were no other days when the temperature approached the freezing mark, so St. 云的 likely first frost will hold off until Saturday (Oct 4), which would rank right about average. 的 early frost did damage some of the corn crop, but conditions widely varied.

的 cause of some of the extremes was one strong surges of northwest-to-southeast steering winds that brought really chilly air from central Canada into central Minnesota around September 9-15. This separated two periods of southwest-to-northeast steering winds, one the first week of the month, and the second after the last cool push moved out of the state. 有时, high temperatures were tempered, 即使是在温暖的模式下, 乌云密布, even if there wasn't much rainfall. However, that accounts for the long stretches of mild lows (lows of 55 degrees or higher on 13 days).

的 northwest-to-southeast flow pattern is reasserting itself in early October, with a strong cold push likely to produce additional frosts and perhaps a hard freeze in the first week of October.

    2014年9月统计数据