The SWPC has not released a map showing the aurora’s potential southern range, as it sometimes does. However, the above map, or a map from the SWPC in September, can provide some context for how far south you might see the Northern Lights during a G3 geomagnetic storm.
You will see an area around the yellow line on the September map. These include northern Idaho, part of Illinois and Indiana, northern Iowa, Maine, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, northern Nebraska, New York, North Dakota, South Dakota, Vermont, Washington, Wisconsin, and Wyoming Besides all of Alaska and Canada. However, the Northern Lights are not exactly rare in Alaska and Northern Canada.
The map shared by Space Weather Watch also includes portions of Connecticut, Missouri, Nebraska, New Jersey, Ohio, Oregon, Rhode Island, and West Virginia. These are all possibilities if we are lucky. The further south you go on the map, even within the marked area, the less likely you are to see the aurora. Even the northern areas of this map are never guaranteed.
During the G1 clocks (the timing is given below) you can see that the southern range is closer to the green line on the map from September onwards. That only includes the northernmost parts of the country. It touches the northern parts of Montana, North Dakota, Minnesota, Wisconsin, Michigan, and Maine.
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