Summer is no doubt known for its warmth, but much of the world, including here in the US and in Louisville, has seen significantly warmer Summers over the last 50 years. Let's take a look at some cool data!
According to Climate Central:
- Since 1970, 96% (235) of 246 U.S. locations had an increase in their summer average temperature and 81% (200) had 7 or more summer days above normal since 1970.
- Over the last 52 years, summer warming was greatest in the western and southwestern U.S.
June 1st was the official start of Meteorological Summer, with the actual start of Summer not far behind later this month on June 21st.
It's important to remember that with hotter summers comes an increased risk for heat-related illnesses that cause more deaths per year in the US than any other weather event.
Image courtesy of Climate Central
52 years of summer warming. A Climate Central looked at 52 years (1970-2021) of summer temperature data in 246 U.S. locations, and found that:
- Average summer temperatures are rising. 96% (235) of the locations analyzed had an increase in average summer temperature. 53% (126 of 235) of those locations warmed by 2°F or more.
- Summer warming was greatest in the western and southwestern U.S. The three greatest increases in summer average temperatures since 1970 were in Reno, Nev. (10.9°F), Las Vegas, Nev. (5.8°F), and Boise, Idaho (5.6°F).
- More summer days above normal. Since 1970, 81% (200) of locations had 7 or more days above their 1991-2020 summer normal temperature. And 37 locations had 30 or more summer days above normal.
Those are some crazy stats to think about! You may have noticed if you were alive in the 1970s, that Summer are indeed hotter here in Louisville as well.
With that being said, let's take a look at some Summer heating stats for our own city.
Since 1970, Louisville has seen an increase of 3.4F degrees in our average Summer temperature high. That is a big jump!
Image courtesy of Climate Central
"Above Normal" temperature days are also increasing a lot for the Louisville area in particular over the past 50 years, seeing an increase of 25 days above normal during the Summer nowadays (around 50 days above average total) compared to only around 25 days above normal in 1970.
Image courtesy of Climate Central
Extreme Heat Can Be A Health Hazard
Climate Central writes...
Exposure to extreme heat makes it difficult for our bodies to cool off, resulting in heat-related illnesses including heat cramps, heat exhaustion, and potentially fatal medical emergencies like heat stroke.
Summer heat can also exacerbate poor air quality by trapping harmful pollutants close to the Earth’s surface and creating ground-level ozone. These pollutants can exacerbate respiratory issues in people with asthma and other lung diseases.
From 1979 to 2018, more than 11,000 Americans died from heat-related illness. In a recent study, researchers concluded that heat-related deaths in the U.S. may be “substantially larger than previously reported.”
According to The Centers for Disease Control and Prevention, the most vulnerable populations to excessive heat areinfants and children, athletes, adults over 65, outdoor workers, low income households, and people with chronic medical conditions.
A big reason why Louisville in particular has gotten so much warmer over the past 50 years could and is likely due to urban development. You may have heard us mention the Urban Heat Island before, where the city is much warmer than surrounding areas. You can find more on that from our own article here.
So, if you step out this summer and think that it didn't use to be this hot all the time during the Summer around here, you're not crazy, you're actually correct!
