Jeffers Foundation


Data from Freshwater Society Minnesota Weatherguide Environment Calendar and Almanac (Jim Gilbert for Phenology and Rod Nerdahl for Astronomy)


Phenology: Third Week of October

The woods are still illuminated with fantastic reds, burntoranges, and goldenyellows of the sugar maples; sunny-yellows of hackberry and wild grape leaves; and bright red of staghorn sumacs and Virginia creeper vines. Migrating birds include common loons, white-throated sparrows, and yellowrumped warblers. Waterfowl watchers keep an eye out for redheads, canvasbacks, lesser scaup, and northern shovelers.

October 16, 2015: Cold temperatures and the first frost over many parts of southern Minnesota killed tomato, salvia, zinnia, and other plants, and iced-over birdbaths.

October 17, 2015: In the Lutsen/Grand Marais area, lingering fall colors included golden-yellow aspens, and golden-yellow and red mountain maples. Observers saw flocks of migrating snow buntings, Lapland longspurs, horned larks, and dark-eyed juncos.

View the October Phenology Information from the Freshwater Society Minnesota Weatherguide Environment Calendar and Almanac >>

Species of the Month

Great blue heron (Ardea herodias)

Great blue heron (<em>Ardea herodias</em>)
Don Specht

The majestic great blue heron populates Minnesota from March through October, nesting in treetop colonies near open water. Both male and female build a platform nest and share responsibility for incubating three to five eggs and feeding the young.

Great blue herons can be seen standing silently along rivers or lakeshores, scanning for prey. Though they walk slowly through water, they can strike quickly to catch fish, crayfish, frogs, and other small animals. Highly adaptable, the great blue heron thrives in all kinds of waters from swamps to desert rivers to the coastline of southern Alaska.

Astronomy: October

October 15 at 8 pm CDT
October 15 at 8 pm CDT
One of the most famous stars in the fall sky is Algol. This star's name means "the ghoul," referring to variations in its brightness noticed by ancient skywatchers. Most of time, Algol appears as a second magnitude star. Every 2.9 days the star dims by a little more than one magnitude, becoming a third magnitude star for about three hours. This change is easy to see. Locate Algol midway between the W-shaped constellation Cassiopeia and the Seven Sisters star cluster. Check Algol's brightness at 8 pm and then again at 10:45 pm to observe Algol's famous "wink."

Morning Stars

Venus has been getting lower every morning since early August. Next month, it will disappear into the Sun's glare. To see Venus before it departs, look approximately eight degrees above the eastern horizon one hour before sunrise. Mars climbs higher in the pre-dawn sky, passing Venus on October 5. This conjunction is a very close one, the planets will be just one-fourth of a degree apart - half the apparent width of the Moon! On the morning of October 17, the Moon will pass Venus and Mars, a fitting finale to the events involving Venus and Mars this month.

Evening Stars

Mercury enters the evening sky on October 8, but remains too close to the Sun to see. Jupiter leaves the evening sky on October 26. Like Mercury, it is also too close to the Sun to see. So, Saturn is the only planet visible after sunset. To see it, look about 15 degrees above the southwestern horizon 60 minutes after sunset. The Moon passes Saturn on October 24.

Sun Declination

View the October Astronomy Information from the Freshwater Society Minnesota Weatherguide Environment Calendar and Almanac >>


Peak day for autumn foliage colors (Twin Cities):
2015 October 14
2014 October 14
2013 October 13
2012 October 1
2011 October 4




5th, Full Moon (Harvest Moon) - 1:40 pm

7th, Mars at aphelion; Mars-Sun distance = 154,872,555 miles - 5:07 pm

9th, Moon perigee; 227,953 miles - 12:51 am

12th, Last Quarter Moon - 7:25 am

15th, Regulus 0.2 degrees north of Moon (Occultation 4:45-5:18 am) - 5:03 am

15th, Variable star, Algol, at min brightness (+3.4) - 10:46 pm

19th, New Moon Freezing (Ojibwe) - 2:12 pm

21st, Orionid Meteor Shower peak - 5:54 am

24th, Moon apogee; 251,757 miles - 9:26 pm

27th, First Quarter Moon - 5:22 pm

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