Plan the Seattle, WA to Portland, OR drive with real weather risk, fuel savings, and a clear-eyed comparison of your alternatives.
Moderate year-round. Atmospheric rivers cause heavy rain and hydroplaning risk along the I-5 corridor Oct–Apr.
Open the live RouteWeather planner → to see today's exact conditions for every waypoint on this drive.
Based on a 25 MPG vehicle and the AAA WA state average of $3.75/gal.
| Metric | Value |
|---|---|
| Distance | 175 miles |
| Fuel needed (25 MPG) | ~7 gallons |
| State avg price (WA) | $3.75/gal |
| Est. fuel cost | $18–$25 |
RouteWeather identifies gas stops ~every 60 miles. Current best discount: ~$3.47/gal (SAVE 7%) vs. WA average. How is this calculated?
Avoid Friday afternoons and Sunday evenings. Best: Tuesday–Thursday before 10 AM.
The Seattle to Portland drive is approximately 175 miles along I-5 South and takes around 3 hours under normal traffic conditions.
Drive or take Amtrak. Flying from SEA to PDX is rarely faster once you account for airport security and baggage. Amtrak Cascades is scenic and often the same time as driving with traffic.
Heavy rainfall from October through April is the primary hazard. Watch for hydroplaning on wet I-5 and reduced visibility near Chehalis, which sits in a low-elevation fog pocket.