Is Seattle Humid? (Yes, but it’s not what you think…)

I was in Phoenix on vacation recently and went to Target to pick up some cough medicine for a sick friend. As I handed the cashier my driver’s license, he said, “What’s the weather like up there? Do you get a lot of humidity?”

I paused for a second and thought, “Humidity? Seattle?” It’s not the first word I’d use to describe our climate. I was also running on fumes at the time, and thankfully one of my friends jumped in and answered for me.

But it did get me thinking—do people think Seattle is humid?

Let’s take a look at what humidity actually means, and then whether or not the term really applies to Seattle’s climate.

What is Humidity?

Most people are vaguely familiar with the idea of humidity but probably couldn’t give you a solid definition. I ran an informal poll of friends after I got home and… yeah, confirmed.

Humidity refers to the amount of water vapor in the air. It’s why your skin feels sticky in the summer or dry and itchy in the winter. It’s also why we use humidifiers and dehumidifiers to regulate comfort inside our homes.

There are a few different ways to measure humidity, but the one most people talk about is relative humidity—which is the amount of water vapor in the air compared to the maximum amount the air can hold at a given temperature.

For example, if the thermostat says it’s 72°F but it feels warmer than that, it might be because the relative humidity is high and the moisture is holding in the heat. On the flip side, if your skin feels dry or your nose is irritated, the humidity might be too low.

One weird fact: it’s usually more humid indoors than it is outside. That’s because air conditioning cools the air without always removing moisture—and it circulates that damp air inside a closed space.

And yes, if you’ve ever heard someone in Arizona say, “It’s a dry heat,” that’s what they’re talking about. Phoenix is hot, but when the humidity is low, the sweat on your skin can actually evaporate—helping you feel cooler. (Unless it’s monsoon season. Then… not so much.)

Is Seattle Humid?

When I got back to town, I started asking around: “Do you think Seattle is humid?”

Most people laughed and said no. A few asked what humidity actually meant. At least two said, “I’ve never thought about it.”

But here’s the kicker: Seattle consistently ranks among the top 50 most humid cities in the U.S. And among large cities (over one million people), it’s even in the top ten.

So yes—Seattle is humid. But it’s also true that it doesn’t feel that way most of the time, especially compared to places like Texas, Florida, or even parts of Alaska or Utah.

The reason for this paradox comes down to geography. Seattle sits on the edge of Puget Sound, a saltwater inlet of the Pacific Ocean. All that water = lots of evaporation. And all that evaporated moisture = humidity.

So why doesn’t it feel muggy? That’s where Seattle’s mountain buffers come in. The surrounding ranges help regulate the climate, keep temperatures relatively cool, and prevent that “sticky” feeling that usually goes hand-in-hand with humidity.

Some Stats on Seattle Humidity

• Average humidity in summer: around 66%
• Average humidity in winter: closer to 80%

For reference, the upper limit of what most people consider “comfortable” is about 55–60%. So we’re regularly above that year-round.

Want to experience peak Seattle humidity? Step outside just after midnight. Nighttime humidity is almost always higher—because when temperatures drop, the air can’t hold as much moisture. As I’m writing this, tonight’s forecasted relative humidity is 91%.

That’s also why winter tends to be more humid than summer: less sun means cooler air, which leads to higher relative humidity.

Final Thoughts

So, is Seattle humid? Yes. But it’s also pleasantly humid—the kind that keeps your skin from drying out without making you feel like you’re wearing the air.

Seattle’s marine climate causes the humidity, and the surrounding geography keeps it from becoming oppressive. Honestly, I’ll take it over Houston’s swampy heat 99 times out of 99.

If you’re planning a trip to the Pacific Northwest, be aware that there is some humidity—but it’s not usually something you’ll notice unless you’re sensitive to it. Staying hydrated, especially if you have a respiratory condition, is always a good idea.

In the end, Seattle’s humidity might be one of the city’s most misunderstood weather traits. But once you get here, you’ll realize it’s not really a drawback—it’s just part of the charm.