Folk singer Willow and her band will perform at 9 p.m. Friday, April 18 at the Voodoo Room, 1102 Marine Drive. Cover is $4.

The music of Willow is linked closely to the weather. Because she makes her home in Seattle, smack dab in the middle of the drizzly Pacific Northwest, the correlation isn’t conducive to upbeat pop.

“I do definitely connect spirituality to the Earth’s cycles and seasons,” Willow, 29, said. “Most of my music tends to be very introspective because of that … I tend to write most of my songs in autumn and winter.”

The result is a collection of acoustic songs, as gathered on her self-published, self-titled 1999 debut. On the recording, Willow’s voice, which draws comparisons to Natalie Merchant and Joan Baez, ranges form a hushed lullaby to a soaring, anguished wail, as she explores themes of personal anguish and religious doubt.