Whatcom County is under a heat advisory and an air quality alert through Wednesday evening, July 22, with conditions expected to ease overnight before a round of showers arrives Thursday morning. The county's Division of Emergency Management issued its daily briefing Tuesday laying out the full picture for residents navigating the mid-week weather event.
What the Advisories Mean
The National Weather Service issued a heat advisory for the lowlands, foothills, and valleys of Whatcom County from 10 a.m. Tuesday, July 21 through 11 p.m. Wednesday, July 22. Temperatures are running warmer than average for the stretch, and the combination of heat and smoke is creating an elevated risk of heat-related illness, particularly for older adults, young children, and people with respiratory conditions. The NWS characterizes the risk as moderate, meaning otherwise healthy people who spend extended time outdoors or in poorly ventilated spaces without cooling could experience symptoms including dizziness, cramping, and heat exhaustion.
The air quality alert, issued separately by the National Weather Service, covers Whatcom County through 9 a.m. Wednesday. Air quality this week has been in the moderate to unhealthy-for-sensitive-groups range, driven by wildfire smoke from fires in British Columbia and central Washington. The Northwest Clean Air Agency is providing real-time air quality readings for the region. Residents with asthma, heart disease, or other conditions that make them vulnerable to smoke should limit time outdoors while the alert is in effect and keep windows closed during peak afternoon hours. Running an air conditioner on recirculate mode, rather than drawing in outside air, can also reduce indoor smoke exposure significantly during the peak of the advisory period.
The Department of Natural Resources has rated fire danger for the Whatcom County lowlands at High, with the Cascades rated between Moderate and High. A Stage 2 burn ban has been in place county-wide since 8 a.m. on July 17 and remains in effect until further notice. All open burning is prohibited under the Stage 2 level, including agricultural burning and recreational campfires in unincorporated areas of the county. Violations of an active burn ban can result in fines, and the DNR and county fire marshals have authority to enforce compliance.
The Rest of the Week's Forecast
After the heat peaks Wednesday, conditions shift notably. A few rain showers are expected Thursday morning, with thunderstorms also possible during the day. The county briefing notes that Thursday night, Friday, and Friday night look dry before rain showers return Saturday morning and continue at times through the day. Saturday night and Sunday are expected to be dry again, offering a window of more comfortable conditions heading into the last weekend of July.
The county briefing indicates no weather concerns through Wednesday as the dry pattern continues, with winds remaining relatively light across the lowlands and valleys. Air quality levels are expected to be unhealthy for sensitive groups through Tuesday evening, then improve overnight as cooler air and eventual precipitation help clear residual smoke from the atmosphere. People who have been keeping windows shut and limiting outdoor activity should see some relief by Wednesday morning even before the Thursday rain arrives.
Coastal and strait conditions through Wednesday include light and variable winds with wave heights around two feet or less. Stronger onshore flow is expected to resume in the latter half of the week as a thermal trough that has been sitting along the Pacific coastline shifts eastward. This thermal trough pattern, where inland heating draws air off the ocean, is a recurring summer feature in northwest Washington that tends to bring calm marine conditions during the heat itself but can deliver strong westerly flow as the trough breaks down. Boaters and paddlers on Bellingham Bay and the Strait of Georgia should check updated marine forecasts before heading out Thursday or Friday as conditions change more rapidly during the transition period.
Drought Context and What Residents Should Know
Washington State's Department of Ecology declared a drought for Whatcom County on April 8, 2026. While the U.S. Drought Monitor does not currently list the county in formal drought status, the state designation reflects low snowpack and reduced streamflows that have been building since early spring. The dry weather pattern through this week extends the period without significant rainfall, which matters for wildfire risk and water supply planning. Streamflows on tributaries that depend heavily on snowmelt, including sections of the Nooksack River system, are running below typical July averages, and that reduced flow affects both water availability and aquatic habitat for salmon and other species.
Residents can sign up for emergency alerts through WhatcomReady, the county's alert and warning system. The Division of Emergency Management notes that the Emergency Operations Center is not currently activated, meaning there is no imminent life-safety emergency requiring a coordinated response. That can change quickly during high-fire-danger periods, so staying signed up for alerts is the most reliable way to get timely information if conditions worsen. The county's alert system is capable of sending notifications by text, phone call, and email depending on resident preferences.
For residents who want to contribute to long-term disaster preparedness, the county is still accepting public input through its Hazard Mitigation Plan survey, though comments submitted after July 1 will not be included in the current update cycle. The Hazard Mitigation Plan is a federally required document that identifies the county's most significant natural and human-caused hazards, assesses vulnerability, and outlines mitigation strategies that reduce risk over time. Community Emergency Response Team training classes are also ongoing for those interested in building personal and neighborhood resilience. CERT training equips community members with basic emergency skills including first aid, light search and rescue, and fire suppression so that neighborhoods can function more independently during the first critical hours of a disaster before professional responders arrive. Details and sign-up links are available through the county's emergency management division.
