Weather Forecasts, Road Conditions, and Weather Radar for I-5

Road Trip and Weather Conditions for Interstate I-5

Interstate I-5 is the main arterial interstate for the west coast of the United States. It runs north-south from Blaine, Washington, to Chula Vista, California (near San Diego). It is the only interstate in the US that connects from a border crossing of Canada to a border crossing of Mexico. Along the way, it crosses through the states of Washington, Oregon, and California, running 1,381 miles in length.

Interstate I-5 passes through many of the largest cities of the west coast. It passes through Seattle, Washington, Portland, Oregon, and Sacramento, Los Angeles, and San Diego, California. At the San Ysidro Port of Entry at the Mexico border, over 70,000 vehicles cross the border every day. At the northern border, at the Peach Arch Border Crossing into Canada, about 4,800 cars cross the border every day (trucks are prohibited at this crossing and must cross the Pacific Highway Border Crossing roughly one mile to the east).

Weather Conditions for Interstate I-5

The Pacific Northwest experiences heavy rainfall throughout the year, as a natural rainforest climate zone stretching from the Canadian border, through Washington, and ending south of Portland, Oregon. Rainfall plus snowfall in some areas average up to 167 inches of rain each year. Heavy fog is also common throughout this area.

Between the border of Oregon and California, I-5 crosses its highest point over the pass of Siskiyou Summit. The pass sits 4,310 feet above sea level and the pass experiences a 2,300 foot elevation change within a 6 mile span. Heavy snow is common from November through April.

Weather Conditions in Washington on I-5

The weather in Washington on Interstate I-5 varies depending on the season. In the summer, temperatures can reach into the 90s with some humidity. The nights are usually still warm and pleasant. In the winter, temperatures can dip below freezing and snow is common. The area is known for heavy rains throughout the year.

The Cascade Mountains provide a barrier to the moist Pacific air. The area can be quite wet, especially in the winter and spring. The high mountains also create a wind tunnel effect, which can cause windy conditions all year long. There can also be high winds in the winter due to storms coming in off the coast. No matter what time of year, it is important to be prepared for the weather in Washington on Interstate I-5.

Weather Conditions in Oregon on I-5

Oregon's Interstate I-5 runs from the California border in the south to the Washington border in the north, passing through many cities and towns throughout the state. As a result, the weather conditions vary greatly along the route.

In the south, temperatures can get quite hot in the summer months, with temperatures reaching as high as 100°F. However, the temperatures usually stay below 90°F. Rainfall is usually light but can be heavy at times.

In central Oregon, temperatures tend to be cooler, with highs in the summer months typically ranging from the mid 70s to low 80s. Rainfall is much heavier in this region, with some areas receiving over 50 inches of rain each year. Snowfall is also possible during the winter months.

In the north, temperatures are even cooler, with highs in the summer months typically reaching only the mid 60s. Rainfall is also very heavy in this region, with some areas receiving over 80 inches of rain each year. Snowfall is possible during the winter months, but it is usually light.

In general, the weather along Interstate I-5 in Oregon can be quite variable, with temperatures ranging from hot to cold and rainfall from light to heavy. Travelers should be prepared for any type of weather conditions when traveling on I-5.

Weather Conditions in California on I-5

California's weather along Interstate I-5 can vary greatly depending on the time of year and the region.

During the winter months, temperatures can range from mild to cold in the north. Meanwhile, the south can experience temperatures in the mid-60s. Rainfall is common in the winter, especially in the northern part of the state. Snow is possible, but rare.

Spring brings warmer temperatures and less rainfall across the state. The northern part of the state can still experience showers. Summer is generally hot and dry along I-5, with temperatures in the mid-80s in the north and mid-90s in the south. Fall can be mild, but it can also bring occasional showers and thunderstorms.

Major Junctions of I-5

In Washington:

• I-5 South begins at the Canada-US border in Blaine, Washington.
• I-5 has a major junction at I-405 in Lynnwood, Washington.
• I-5 has a major junction at I-90 in Seattle, Washington.
• I-5 has a major junction at I-405 in Tukwila, Washington.
• I-5 has a major junction at I-705 in Tacoma, Washington.
• I-5 has a major junction at I-205 in Salmon Creek, Washington.

In Oregon:

• I-5 has major junctions at I-84 and I-405 in Portland, Oregon.
• I-5 has a major junction at I-205 in Tualatin, Oregon.
• I-5 has a major junction at I-105 in Eugene, Oregon.

In California:

• I-5 has a major junction at US-97 in Weed, California.
• I-5 has a major junction at I-505 in Dunnigan, California.
• I-5 has major junctions at I-80 and I-305 in Sacramento, California.
• I-5 has a major junction at I-205 in Lathrop, California.
• I-5 has a major junction at I-580 in Vernalis, California.
• I-5 has a major junction at I-210 in Sylmar, California.
• I-5 has a major junction at I-405 in Mission Hills, California.
• I-5 has a major junction at I-10 in Boyle Heights, California.
• I-5 has a major junction at I-710 in Commerce, California.
• I-5 has a major junction at I-605 in Downey, California.
• I-5 has a major junction at I-405 in Irvine, California.
• I-5 has a major junction at I-8 in San Diego, California.
• I-5 has a major junction at I-805 in San Ysidro, California.
• I-5 North begins at the Mexico-US border in San Ysidro, California.

This map shows the current & 7-day weather forecast, road conditions, and weather radar for all of US interstate I-5.