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Joint Base Lewis-McChord
JBLM Weather: What To Expect When Moving Here
JBLM Weather: What To Expect When Moving HereJBLM Weather: What To Expect When Moving Here

JBLM Weather: What To Expect When Moving Here


If you’re headed to Joint Base Lewis-McChord (JBLM), south of Tacoma in Washington, you’ll enjoy the Pacific Northwest’s four distinct seasons. Summers are warm but short, and winters are cold and wet. Read on to find out more about the weather at Joint Base Lewis-McChord so you can be prepared for any activity, whether it be extensive outdoor training or leisurely evenings spent in your own backyard.

Suggested Read: Joint Base Lewis McChord: In-Depth Welcome Center


High temps: Mid 50s to mid 60s
Low temps: High 30s to mid 40s

Spring days and nights are fairly cool at Joint Base Lewis-McChord. Keep away the chill with warm layers and keep an umbrella handy for rainy spring days. And while it may be true that “April showers bring May flowers,” you should know that rain falls throughout the year at Joint Base Lewis-McChord. An average of 41 inches of precipitation falls annually, with October through March being the rainiest months.

JBLM Weather in the Summer


High temps: Low to high 70s
Low temps: Low 50s

Summers at Joint Base Lewis-McChord are mild and dry. Days are warm, but nights are still chilly in the Pacific Northwest. Dressing in layers is a great way to adjust to the varying temperatures throughout the day. Light fabrics and colors can help you stay cool on the occasional scorcher. Don’t forget to put on sunscreen, even when there’s cloud cover. You can still get sunburn on a cloudy day!


High temps: Low 50s to low 70s
Low temps: High 30s to high 40s

Fall at Joint Base Lewis-McChord is colorful and cool. The leaves put on a vibrant show that you won’t want to miss, but you’ll be reaching for your jacket when you head out the door. Dress in layers to stay comfortable throughout the day.


High temps: High 40s to low 50s
Low temps: Mid 30s

Joint Base Lewis-McChord has cold winters, but snowstorms are rare. The yearly average snowfall for the base is only about 5 inches. Warm clothing for cooler winter temperatures will help you stay toasty, even when Jack Frost comes for a visit. Winter jackets, fleece sweaters and pullovers, wool socks, gloves, and tightly knit caps can all help keep heat close.

Weather Hazards at Joint Base Lewis-McChord

Weather Hazards at Joint Base Lewis-McChord

Possible weather hazards at Joint Base Lewis-McChord include earthquakes, thunderstorms, floods, tornadoes, and winter storms. For more information on protecting yourself from adverse weather and other local hazards at Joint Base Lewis-McChord, check out the Washington State Emergency Management Division website.


According to the Washington State Emergency Management Division, more than 1,000 earthquakes occur in the state each year. Besides the damage from the shaking, earthquakes can trigger landslides, surface fault ruptures and liquefaction, all of which can cause injury or property damage. Contact your local city or county government for information on how to be prepared where you live.


A severe thunderstorm can knock out power; bring high winds, lightning, flash floods, and hail; and spin into a twister in seconds. Pay attention to storm warnings.

Remember the rule: “When thunder roars, head indoors.”

The National Weather Service recommends following the 30/30 rule: People should seek shelter if the “flash-to-bang” delay — the length of time in seconds from the sight of the lightning flash to the arrival of its subsequent thunder — is 30 seconds or less, and remain under cover for 30 minutes after the final thunderclap.


Floods are the most common natural disaster in the United States. If you are outdoors during a rainstorm, seek higher ground. Avoid walking through any floodwaters — even water 6 inches deep can sweep you off your feet. If you are driving, avoid flooded areas. The majority of deaths in floods occur when people drive through flooded areas. Roads concealed by water may not be intact. Water only a foot deep can displace a vehicle. If your vehicle stalls, leave it immediately and seek higher ground. Rapidly rising water can engulf a vehicle and sweep it away.

Tornadoes Warnings


Tornadoes may happen at any time of the year. Tornadoes can develop quickly, with minimal warning, so it is important to have a plan in place before they occur. If a tornado watch is issued, that means weather conditions favor the formation of tornadoes, such as during a severe thunderstorm. A tornado warning is issued when a tornado funnel is sighted or indicated by weather radar. You should take shelter immediately during a tornado warning.

Winter Storms

Joint Base Lewis-McChord has mild winters, but winter storms are still possible.

Prepare for winter storms by assembling a disaster supply kit for your home and vehicle. Have your car winterized before the winter storm season arrives. Listen to weather forecasts and plan ahead.

When winter storms and blizzards hit, dangers include strong winds, blinding snow, and frigid wind chills. Avoid unnecessary travel during storm watches and warnings and stay indoors.

Winter storms can also cause power outages. During a power outage, gather in a central room with an alternative heat source. Use fireplaces, wood stoves, and other heaters only if they are properly vented to the outside. Never use an electric generator or a gas or charcoal grill indoors. The fumes are deadly. If you use a space heater, keep the heater away from any object that may catch fire (drapes, furniture, or bedding) and never leave it unattended. Avoid letting pipes freeze and rupture by leaving faucets slightly open so they drip continuously.

For more information on weather and winter commutes at Joint Base Lewis-McChord, visit the base’s weather and road conditions website.

Field & Training Expectations

Field & Training Expectations

From warm summer days to cold winter nights, Joint Base Lewis-McChord experiences a wide range of weather. But, with few exceptions, the military doesn’t stop training exercises for colder temps or heat waves. Be sure to bring or acquire an assortment of personal field gear that can handle any situation, whether you’re training with weapons in January or running an obstacle course in July. A wide range of uniforms and clothing is important to remain healthy and effective in the field from the cold nights of winter to the hot days of summer.

If summer days are dangerously hot, which is rare at Joint Base Lewis-McChord, service members will be notified of red or black flag conditions, which they display on their Facebook page. During these days, outdoor training may be interrupted or postponed to avoid heat illness among personnel.


With preparation and adaptation, you’ll appreciate all four seasons at your new home at Joint Base Lewis-McChord. And if you’re still not sure what the day ahead will bring, you can always check the latest forecasts and other related announcements online or from local news stations.


The appearance of U.S. Department of Defense (DoD) visual information does not imply or constitute DoD endorsement.

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