Whew — those couple of 90°F days over the weekend were enough to give us flashbacks of last year’s heat dome. And apparently, we weren’t the only ones.

Earlier this week as we passed the anniversary of the hottest day Seattle (and other parts of Washington) has ever seen, King County released its new Extreme Heat Mitigation Plan that is intended to… well, cool things off a bit.

The plan includes a number of long-term and short-term strategies — such as updating building codes and planting more trees to create shady bus shelters.

The left map shows how much more quickly some areas of Seattle cool off. | Chart via King County

🌳 Under the shade

While adding extra trees does have the immediate effect of creating some shade for Seattleites to cool off under, landscaping + vegetation have a much larger impact on air temperature.

In 2020, the city conducted a heat mapping project that was intended to identify the ways in which intensifying heat was impacting the metro area. The study showed that while temperatures looked consistently warm across the city during the afternoons, areas with lots of landscaping cooled off much more quickly than areas that had little — with communities between Renton and Auburn remaining under the sweat-inducing heat the longest.

To help balance the effects, part of the Extreme Heat Mitigation Plan is to ramp up the city’s 3 Million Trees initiative a notch + prioritize tree planting in areas that generally take the longest to cool off.

Plus, the city plans to look for opportunities to de-pave more areas to make way for green space and build more neighborhood "water features" for residents to cool off in.
Alongside this:

King County Metro will use the data to inform its plans for future bus shelter projects.
The King County Land Conservation Initiative will prioritize permanent protection of greenspaces in these areas.
King County Parks will use the map to build park designs and improvements that take these temperatures into account.

🏢 Keeping that office cool

Fans only do so much when temperatures start to rise. To ease the stress, King County is looking to invest its efforts heavily in creating more energy-efficient homes, public spaces, and commercial buildings since this type of infrastructure is intended to insulate and keep indoor spaces at a constant temperature.

They’ll do this by:

Incentivizing landlords to upgrade units with better heat protection
Changing building code requirements to be more energy efficient
Replacing gas, oil, and electric furnaces/air conditioners in low-income homes with more efficient heat pumps
Offering private loans to commercial + multi-family residences who make the upgrades

⛑️ Safety first

Additionally, King County has:

Updated + distributed multi-language informational sheets about how to stay safe during heat waves
Increased the number of languages public health alerts are sent out in from two to nine
Updated public health recommendations to better align with the National Weather Service’s