U.S. Temperature Attribution Overview: November 2024

Analysis: How climate change boosted United States temperatures in November 2024

Using Climate Central’s Climate Shift Index (CSI) tool to measure the impact of climate change on daily temperatures across the United States, as well as NOAA’s Applied Climate Information System (ACIS) to find daily temperature information, we have compiled a high-level overview of how climate change has affected temperature trends in November in cities across the United States. Download full report (PDF)

1. High level findings (download local data, including monthly precipitation)

• November temperature anomalies in the U.S. were elevated across much of the country: 166 out of 191 analyzed cities were warmer than normal. The highest anomalies stretched from the Rocky Mountains eastwards (Figure 1).

• This was the hottest November on record in 15 cities – including all 5 cities in Louisiana – and was in the top 5 hottest Novembers for an additional 38 cities.

• The South showed particularly elevated November temperatures, where cities on average were 5.7°F warmer than average.

• Climate Shift Index (CSI) values meanwhile followed a different trend: States with coastlines along the Gulf of Mexico stood out as the states with cities experiencing the highest number of days with climate change-influenced temperatures at or above CSI 3 (temperatures made at least 3x more likely because of climate change) (Figure 2).

• In general, cities across the country did not experience many days with CSI values at or above 3. However, a CSI level 3 indicates a very strong climate influence on a day's temperatures. The high variability inherent in fall weather means that CSI levels of 3 or higher are extremely rare during November. The strong temperature anomalies and long-term warming trends during November (see our 2024 Fall Package) indicate that climate change is influencing fall conditions, although the signal is less clear at the daily scale.

Figure 1. Threaded ACIS temperature anomalies for November 2024  relative to the 1991-2020 standard normal period. Analysis based on ACIS data.

Figure 2. Days with a CSI of 3 or higher for November 2024 for ACIS threaded stations. Analysis based on ERA5 data (November 1-28) and GFS data (November 29-30).

2. Local temperature anomaly analysis (download local data, including monthly precipitation)

• The most unusually hot city in November was Baton Rouge, Louisiana, where it was 9.7°F hotter than normal.

• 61 cities had November temperature anomalies greater than 5°F. These included 9 in Texas and all 5 in Louisiana.

• The average temperature anomaly across all cities was 3.7°F.

• 182 out of 191 ACIS stations analyzed had positive temperature trends for November, indicating that these cities have been warming on average since 1970.

• El Paso, Texas had an unusually warm November (with an average daily temperature anomaly of 2.6°F), and is the fastest-warming ACIS station for November on average, warming 6.4 °F on average since 1970.

3. Local Climate Shift Index analysis (download local data, including monthly precipitation)

• 12 out of 191 ACIS stations analyzed had at least one week with daily CSI values greater than or equal to 3, indicating that temperatures on those days were made at least three times as likely due to climate change in those cities.

• San Juan, Puerto Rico had 23 days at CSI 5, indicating that temperatures on these days were made at least 5 times more likely to occur because of climate change.

• 8 out of the top 10 cities with the strongest climate signal were in Florida.

Methods

Calculating the Climate Shift Index

All Climate Shift Index (CSI) levels reported in this brief are based on daily average temperatures and  ERA5 data from November 1 to November 28, 2024, and GFS data from November 29 to November 30, 2024. See the frequently asked questions for details on computing the Climate Shift Index, including a summary of the multi-model approach described in Gilford et al. (2022).

City Analysis

We analyzed 191 Applied Climate Information System (ACIS) stations associated with U.S. cities. For each city, we found the CSI time series from the nearest 0.25° grid cell. We calculated the number of days at CSI levels 2, 3, 4, and 5. We used ACIS data to find the average monthly temperatures, temperature anomalies, and precipitation information, and to derive average monthly warming trends for each city.

Click here for more information about the Climate Shift Index

Major funding provided by the Bezos Earth Fund and The Schmidt Family Foundation.