Yes, LA, What You're Feeling Is Humidity. The Science Behind That Sticky, Gross Sensation
Honestly, I kind of forgot about humidity.
It’s been so damn dry all year, my often dehydrated brain has humidity amnesia. But apparently, this sticky, moist weather is pretty average for a SoCal summer.
National Weather Service meteorologist Joe Sirard said by July, the summer heat warms up the ocean enough to create more vapor in the air.
“So it does feel a little sticky out there," he said, "especially the further inland you go into the area."
But what is it about this kind of weather that makes us really feel the humidity in the air?
Well, it's not just plain humidity percentages that meteorologists track. The dew point really captures how we experience the humidity, and in the past few muggy days, the L.A. region has had a dew point in the 60s — exactly the point where our bodies start to register the humidity around us.
Okay, so then why does feeling humidity also make the air temperature feel warmer?
That’s got to do with what’s called the wet bulb temperature. And that number relates to how the body can cool itself.
Sirard explained that wet bulb temperature is about halfway between the air and the dew point temperatures.
“Say for example it's 80 degrees out, the dew point is 60, then the wet bulb would be around 70ish,” he said. That means when you’re sweating and a breeze blows across your skin, “it'll cool the skin down to like, 70 degrees.”
Downtown L.A. received 0.10" of rain yesterday July 13th, making it the 5th wettest July so far in 144 years since records have been kept since 1877. The wettest July on record was in 2015 with a total of 0.38". #cawx #LArain #LAweather pic.twitter.com/JNEURZTeH5— NWS Los Angeles (@NWSLosAngeles) July 14, 2021
You may have seen the term wet bulb more often in the news lately. Scientists are trying to raise public awareness about the daily wet bulb temperature in an effort to save lives. That’s because high temperatures and humidity caused by climate change are raising the web bulb temperature to where even healthy people cannot regulate their body temperature and could die from heat.
As for the current wet bulb temperature in L.A., we can thank the nearby ocean. With the summer sun higher in the sky, the Pacific is warming up. Onshore winds then carry that water vapor inland.
Today is the start of Monsoon Awareness Week 2021! Each day this week NWS offices across the southwest will post a video on a topic regarding the hazards of the North American monsoon. Follow along with us and the hashtag #Monsoon2k21 each day! Today's topic: what is the monsoon? pic.twitter.com/P0vftBdkkd— NWS Los Angeles (@NWSLosAngeles) June 14, 2021
Some of that vapor has developed into actual rainfall. There even have been some scattered showers in the past week. In a statement that drives home the context of relativity, the National Weather Service reports that Los Angeles is having its fifth wettest July on record (aka since 1877). Which, isn’t saying much. It took just .10 inch of rain in downtown Tuesday to get us there.
There’s also the monsoon moisture that comes to our area in August to early September. And we are seeing a little of that now. “Recently we have been in kind of a monsoon flow as well, so that's also helping to keep these humidities a little bit higher,” Sirard said.
So, if like me you’re hating the humidity, it won’t really pass until the end of summer. But these high levels above 60% should break in just a few more days.
In the meantime, all of our tropical house plants purchased during pandemic lockdown are happy. Let’s focus on that.