In Seattle, the term “spider season” describes a distinct period when these eight-legged creatures become notably more apparent. This phenomenon is a natural and recurring aspect of the local ecosystem, driven by specific biological and environmental factors.
Understanding Seattle’s “Spider Season”
Seattle’s “spider season” typically occurs from late summer through early fall. During these months, residents often notice a surge in spider sightings. This heightened visibility is primarily due to the maturation and increased activity of particular spider species, rather than a sudden population boom. While spiders are present year-round, this period marks a predictable annual event where their presence becomes more pronounced.
Why Spiders Become More Noticeable
Several factors contribute to spiders becoming more noticeable during this time. A significant reason is the onset of mating season for many common species. Male spiders actively leave their secluded habitats in search of females, increasing their chances of being seen as they roam. Additionally, as outdoor temperatures begin to cool with the approach of fall, some spiders may seek warmer, more sheltered environments indoors. The spiders also have had the entire summer to grow, making them larger and more visible.
Common Spiders You Might Encounter
Several spider species are frequently observed during Seattle’s spider season. The Giant House Spider (Eratigena atrica) is one of the largest spiders in Washington State, often seen indoors. These spiders are typically dark brown or gray and can have a leg span of up to 4 inches. Another common species is the Hobo Spider (Eratigena agrestis), which is brown with V-shaped patterns on its abdomen and builds funnel-shaped webs. The Common House Spider (Parasteatoda tepidariorum), a smaller, grayish-brown spider, is also frequently found indoors, often spinning webs in corners.
Living Alongside Seattle’s Spiders
Most spiders encountered in Seattle homes are harmless to humans and play a beneficial role in controlling other household pests. They feed on insects like flies, mosquitoes, ants, and even cockroaches. To manage their presence, seal cracks and gaps around windows and doors to limit entry points. Maintaining a tidy home by regularly vacuuming and decluttering can also reduce hiding spots. If a spider is found indoors, gently relocating it to a garage or crawl space allows it to continue its pest control activities.