Cornelius Oregon Weather

Learn about Cornelius Oregon Weather

Curious about Cornelius Oregon Weather? You’re not alone. People want to know if it’s rainy, how hot summers get, and what to expect for daily life. Here’s the simple answer up front, plus practical tips for commuting, outdoor plans, and moving to this quiet Tualatin Valley city.

Quick Answer

Cornelius Oregon Weather is classic western Oregon: mild, wet winters and dry, pleasantly warm summers. Expect frequent rain from November to March, occasional frost and rare light snow, and long, sunny stretches in July–September. Summer highs usually sit in the upper 70s to mid-80s°F, with a few hotter days. Mornings can be foggy in fall and winter.

What Cornelius Oregon Weather Means

“Cornelius Oregon Weather” describes the temperate, Pacific-influenced climate of the Tualatin Valley, between Hillsboro and Forest Grove. You’ll get:

  • Rainfall concentrated in late fall, winter, and early spring
  • Mild temperatures most of the year
  • Dry, comfortable summers with cool nights
  • Foggy mornings in low-lying areas
  • Rare valley snow, but it can happen

Cornelius sits around 180–200 feet in elevation, about 22 miles west of Portland. It’s slightly cooler at night than downtown Portland and a touch drier than the West Hills.

Why People Search for This in Cornelius, Oregon

  • Commuting and driving: Wet roads, fog, and fall leaves can affect OR-8 (Tualatin Valley Hwy) and nearby rural routes.
  • Outdoor plans: Locals head to Hagg Lake (12–15 miles south), Fernhill Wetlands (10 minutes west), and Jackson Bottom Wetlands (10 minutes east).
  • Home and garden: Rain, moss, and drainage matter for roofs, lawns, and vegetable beds.
  • Wineries & farms: The valley’s vineyards and u-pick farms are seasonal and weather-sensitive.

What to Expect

Here’s the year, at a glance.

  • Winter (Dec–Feb)

    • Highs: 45–50°F; Lows: 33–38°F
    • Frequent rain, short daylight, and morning fog
    • Snow is uncommon, but a few icy mornings happen each winter
    • Occasional wind or cold snaps; brief power outages possible

  • Spring (Mar–May)

    • Highs: 55–68°F
    • Showers and sunbreaks; brighter, longer days
    • Grass pollen can spike; trails can be muddy
    • Great time for waterfalls and green hills

  • Summer (Jun–Sep)

    • Highs: 75–88°F most days; cool nights in the 50s
    • Dry, low humidity; perfect for wineries and lake days
    • A few hot spells into the 90s or, rarely, 100s
    • Wildfire smoke can drift in late summer during regional events

  • Fall (Oct–Nov)

    • Highs: 52–68°F
    • First rains return; leaves make roads slick
    • Crisp days for harvest events in Forest Grove and along OR-47
    • More frequent morning fog

Other notes:

  • Annual rain is roughly 3 to 4 feet, mostly November–March.
  • Freezing rain is unusual but possible during rare cold east-wind events.
  • Valley snow totals vary year to year; some winters see none.

Tips for Visitors / Residents

  • Clothing and gear

    • Wear layers year-round; bring a waterproof jacket October–April.
    • Waterproof shoes help for parks and vineyards in wet months.
    • In summer, carry water and sunscreen; the sun is stronger than it feels.

  • Driving and getting around

    • Leave extra space on wet roads; watch for leaf-slick spots in fall.
    • Fog is common in mornings; use low beams.
    • Heading to the coast via OR-6? In winter, check road conditions—high rain, debris, or snow can affect the pass.

  • Outdoor plans

    • Expect muddy trails in winter/spring at Fernhill and Jackson Bottom.
    • Hagg Lake is great in summer; a day-use fee applies.
    • Start early on hot days; afternoons can get toasty in July–August.

  • Home readiness

    • Clean gutters and moss from roofs each fall.
    • Consider a dehumidifier for basements in rainy months.
    • Keep spare batteries and a flashlight for occasional storm outages.

  • Health and comfort

    • Pollen (grass in late spring) can be intense—check forecasts.
    • On smoky days, limit strenuous outdoor activity and keep windows closed.

Best Local Resources

  • National Weather Service Portland: daily forecasts, alerts
  • ODOT TripCheck: highways and Coast Range pass conditions
  • City of Cornelius and Washington County alerts: local updates
  • PGE Outage Map: power status and restoration estimates
  • Oregon DEQ Air Quality Index: smoke and air quality readings

Frequently Asked Questions About Cornelius Oregon Weather

  • How far is Cornelius from Portland?

    • About 22–25 miles west of downtown Portland; typically 40–60 minutes by car depending on traffic.

  • When’s the best time to visit for dry weather?

    • Late June through September. For mild temps and greenery, May and early October are lovely with a chance of showers.

  • Does it snow in Cornelius?

    • Snow is rare. Some winters see a dusting to a couple of inches; many have none. Ice is more likely than deep snow.

  • Are summers very hot?

    • Usually comfortable: many days in the upper 70s to mid-80s°F. Expect a few hotter days each summer.

  • Is the area kid friendly in rainy months?

    • Yes—bring rain gear and enjoy nearby wetlands, libraries, and indoor rec in Hillsboro and Forest Grove. Parks drain well but can be muddy.

Summary

Cornelius Oregon Weather means mild and green most of the year, with rainy winters and dry, comfortable summers. Plan for layers, waterproof shoes in the wet season, and sunscreen in summer. If you like easy access to parks, wineries, and lake days—with a few foggy mornings—you’ll feel right at home.

  • Moving to Cornelius: Neighborhoods and Commute Basics
  • Best Parks and Nature Walks Near Cornelius
  • Day Trip Guide: Hagg Lake (Henry Hagg Lake)
  • Wineries and Tasting Rooms Around Cornelius and Forest Grove
  • Commuting OR-8 and OR-47: What to Know in Each Season