Can the Woolly Bear Caterpillar really predict Oregon's winter weather?

PORTLAND, Ore. (KOIN) -- If you're out and about on the trails this fall in the Pacific Northwest, you might run into a fuzzy black and orange fellow inching across your path.

The woolly bear caterpillar is also known as the fuzzy bear caterpillar or the woolly worm. The caterpillars have fuzzy bristles that are black on both ends with a band of orange in the middle.

KOIN 6 Meteorologist Kelley Bayern spotted one on a recent fishing trip on the Crooked River in central Oregon.

The Weather Myth

According to old folktales, the amount of orange or rusty color on the woolly caterpillar can describe the severity of the upcoming winter where it was found. If the caterpillar is mostly black, with a more narrow orange band, the upcoming winter may be colder, snowier, and overall more harsh. And vice versa: A woolly bear caterpillar with a wider orange middle section will predict a calmer winter.

The woolly bear caterpillar I found in central Oregon seems to be predicting a harsher winter since the orange bands were fairly narrow. Perhaps it has tapped into an upcoming La Niña pattern coming this winter, which is something that can correlate to a wetter and colder pattern here in the Pacific Northwest across the colder months.

Woolly Bear Debunked

As fun as this myth sounds, a caterpillar simply cannot predict the weather (or Meteorologist Bayern would be out of a job). The caterpillar's color is based more upon its recent diet and age. A better growing season may result in a larger caterpillar with more black coloring.

The caterpillar Bayern found was massive, about three inches long, and likely an older gentleman due to its size and black coloring. She named him Greg.

Fun Facts

There are two generations of these caterpillars every year, one in spring and another in fall. The fall caterpillars are the best forecasters (the most colorful).

Woolly bears feed in the fall in preparation for winter hibernation, where they nearly freeze solid. When springtime arrives, they thaw and become active again.

After waking from a winter hibernation, the caterpillar will feed through spring, then cocoon and emerge as an Isabella Tiger Moth.

Even though the woolly bear caterpillar may give Punxsutawney Phil a run for his money, the best winter forecast will come months from now when we reach the cold season.

Keep and eye on the forecast with the KOIN 6 Weather Team for the latest updates.