The issue of climate change grows more pressing each year. How is it affecting Americans’ daily lives? To find out, Payless Power consulted the World Weather Online API and analyzed daily weather data from January 2009 to October 2023 for the five most populated cities in each U.S. state. In this article, we’ll share our findings and uncover the nationwide evolution of temperatures and sunlight exposure over the past 15 years.
- Florida (74.1 degrees Fahrenheit), Hawaii (73.8 degrees), and Arizona (73.6 degrees) are the hottest U.S. states of the last 15 years, on average.
- Alaska (36.5 degrees), North Dakota (42.3 degrees), and Montana (42.8 degrees) are the coldest U.S. states on average over the last 15 years.
- St. Louis, Missouri, is the hottest U.S. city of the last 15 years, with an average annual temperature of 83.3 degrees.
- Fairbanks, Alaska, is the coldest U.S. city of the last 15 years, with an average annual temperature of 29.5 degrees.
- St. Louis, Missouri, is the sunniest U.S. city, with an annual average of 11.9 hours of daily sunlight over the last 15 years.
Annual Climate Pattern Changes
To begin our 15-year climate exploration, we present maps illustrating annual average, maximum, and minimum temperatures, along with sun hours in each U.S. state. These visuals reveal the climate changes from 2009 to 2023.
Daily Sunlight Hours
Understanding Temperature Changes and Variance
Explore temperature and sun hour shifts in each U.S. state over the past 15 years with our interactive chart below. Select a state from the list of 50 to reveal trends in average, maximum, and minimum annual temperatures, as well as sun exposure changes from 2009 to 2023.
To further express this data and what it means, we ranked each state based on its variance scores. A lower rank indicates more significant fluctuations and less consistent climate patterns, while a higher rank signifies more stable and predictable conditions. This comparison highlights states with the most volatile and consistent climate trends.
North Dakota’s average annual temperature varied the most over the last 15 years, showing significant shifts. In contrast, Hawaii — known for its pleasantly mild temperatures — showed the lowest variance in average annual temperature, suggesting a remarkably stable and predictable climate year over year.
Minnesota topped the list for the highest variance of maximum annual temperatures. This state’s highest recorded maximum temperature was 110 degrees Fahrenheit in 2023, and its lowest maximum temperature was 90 in 2014 and 2019. On the other end of the scale, Vermont exhibited the lowest variance in annual maximum temperatures, indicating a more consistent pattern over the years.
Oklahoma had the most considerable variance among annual minimum temperatures. Residents there experienced drastic fluctuations between a moderate average low of 20 in 2020 and a frigid average low of -15 in 2021. On the other hand, California had the lowest variance in annual minimum temperatures, showing more stable annual lows.
Alaska showed the highest variance in annual average daily sunlight hours over the past 15 years. The state saw its sunniest year in 2014, with an average of 8.9 hours of sunlight per day, compared to 2023, its least sunny year, with only 6.3 hours. This state is known for long periods of darkness and light, with some cities not seeing the sun for over 2 months in winter. On the flip side, Nevada recorded the lowest variance in annual average daily sun hours, exemplifying its consistent levels of sunlight throughout the years.
Hottest and Coldest U.S. States and Cities
This final section reveals the places in the U.S. that have consistently been the hottest, coldest, and sunniest. The following insights, derived from extensive weather data, offer a snapshot of the most extreme climate conditions across the country.
Three states consistently topped the charts in terms of average heat. Florida, with an average annual temperature of 74.1 degrees Fahrenheit, was the hottest state in the U.S. from 2009 to 2023. It was closely followed by Hawaii, where the average temperature has hovered around 73.8, and Arizona, with an average of 73.6. These states, known for their sunny and warm climates, have maintained their reputation as top warm-weather destinations.
On the other end of the spectrum, Alaska, North Dakota, and Montana had been the coldest states. Far from the continental U.S., Alaska had an average annual temperature of just 36.5. North Dakota and Montana followed with average temperatures of 42.3 and 42.8, respectively.
Sunlight is another critical factor in understanding climate trends. Nevada, Arizona, and New Mexico tied for the top spot, each averaging 11.6 hours of sun per day. This large amount of daily sunlight highlights these states’ unique appeal to sun-lovers looking to live in locales with lots of sunshine. However, it can also make these states great places for solar energy production.
We also analyzed daily weather data from January 2009 to October 2023 for the five most populous cities within each U.S. state to see which ones stand out for their extreme weather conditions. The results are below.
St. Louis, Missouri, emerged as a unique urban hotspot in America. With an impressive average annual temperature of 83.3 degrees Fahrenheit, it has consistently been the warmest city in the nation over the last decade and a half. In stark contrast, Fairbanks, Alaska, was the coldest city in the U.S. during this period, with an average annual temperature of just 29.5. This city has also recently experienced record-breaking cold temperatures of 40 degrees below zero.
Meanwhile, St. Louis claimed another winning title — this time for being the sunniest city in the U.S., based on its annual average of 11.9 daily sun hours. This high level of sunlight contributes to its warmth and highlights the city’s potential for energy savings thanks to solar power.
Reflecting on America’s Shifting Climates
We’ve seen significant shifts in climate patterns across the U.S. over the last 15 years. From the sun-drenched streets of St. Louis, Missouri, to the chilly landscapes of Fairbanks, Alaska, these changes can affect millions of lives. Our extensive weather data analysis shows the dynamic nature of our environment, its profound impact on both natural and urban settings, and the importance of being prepared for possible climate fluctuations to come.
For this study, we gathered World Weather Online API daily weather data from January 2009 to October 2023 for the five most populous cities within each U.S. state. In particular, we gathered average temperature, maximum temperature, minimum temperature, and daily sunlight hours. We then converted these statistics to monthly and yearly weather data for each city. We also combined data for each state’s five most populous cities.
About Payless Power
Payless Power, a leader in the energy sector, is dedicated to providing customers with reliable and affordable power solutions. We’re also committed to educating and informing the public on critical issues like climate and energy consumption. Discover how we’re powering homes and empowering minds at PaylessPower.com.
Fair Use Statement
We encourage you to share the findings from this study and the interactive map for noncommercial purposes, provided you attribute the information to Payless Power and include a link back to our page for comprehensive access to our data and tools.