Climate Shift Index Alerts
Using our Climate Shift Index (CSI) system (including Ocean CSI and Tropical Cyclone CSI), we issue alerts when select extreme weather events — such as heat waves, hurricanes, or wildfires — are made more likely by human-caused climate change.
Explore the log below to see a sampling of recent events linked to climate change, and use the CSI and Ocean CSI map tools to investigate daily conditions in your area.
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Europe faces another week of extreme heat, with temperatures up to 14°C (23°F) above average.
Europe faces another week of climate change-driven extreme heat. The prolonged heat wave will stretch through Friday, July 17, with parts of Spain, France and Italy expected to reach 38°C to 40°C (100°F to 104°F). The extreme heat is fueling wildfires in France and carries a strong climate change signal. Climate Shift Index levels indicate human-caused warming made the event at least five times more likely across large parts of the region.
Unusual temperatures:
High temperatures will run well above the mid-July average through Friday, July 17, across Europe, reaching as high as 11°C to 14°C (20°F to 23°F) above average. The United Kingdom, France, and Italy are expected to experience the largest departures from normal.
The hottest temperatures through the week — 38°C to 40°C (100°F to 104°F) — are forecast across parts of eastern Spain, France, and northern Italy.
Wildfires have forced evacuations in the Fontainebleau forest south of Paris, with nearly 2,000 hectares (about 4,900 acres) burned as of Tuesday, July 14.
For the first time, water-dumping planes have scooped water from the Seine River to help contain the fires.
Climate influence:
Climate Shift Index (CSI) levels of 5 — the highest possible — are forecast across Spain, Italy, France, and the United Kingdom, from July 14 through 19, meaning human-caused climate change made this extreme heat at least five times more likely. This signals an exceptional climate-influenced event.
From July 14 to 19, more than 117 million people (45% of the population) across Spain, Italy, France, and the United Kingdom will experience at least one day with maximum temperatures at CSI 5, indicating an exceptional influence from climate change.
Temperatures made at least three times more likely by human-caused climate change are projected to affect approximately 1.4 million square kilometers (540,000 square miles) — about 85% of the combined land area of the countries analyzed.
Another heat dome brings triple-digit temperatures to the northern U.S. as climate change amplifies extreme heat
A sprawling heat dome will bring temperatures in the 90s and triple digits across much of the northern United States this week, from July 13 to 15. Many areas are running 10°F to 25°F above average, and daily records are expected to fall. Climate Shift Index data indicates human-caused climate change made this extreme heat at least three times more likely across large parts of the western and northern U.S., affecting more than 118 million people west of the Mississippi River.
High temperatures in the 90s and into the triple digits will persist this week across the northern and Northeast United States, running 10°F to 15°F above average for mid-July. The heat peaks on July 14, when temperatures are forecast to reach 20°F to 25°F above average in North Dakota, South Dakota, Minnesota, Michigan, and Wisconsin.
The most extreme heat — 100°F to 105°F — is forecast for Tuesday, July 14 and Wednesday, July 15, across parts of Colorado, North and South Dakota, Utah, and Wyoming.
Daily and all-time high temperature records are expected to fall across the northern U.S. through July 15, before the heat dome shifts toward the eastern United States.
The National Weather Service has issued heat alerts for more than two dozen states across the northern and Northeast United States, with alerts in effect through at least Wednesday, July 15.
Humid Heat:
Humidity is helping to drive the persistent heat. Dangerous humid heat due to climate change will impact several states, including North Dakota, Minnesota, Wisconsin, Michigan, Iowa, Illinois, Indiana, Missouri, and Ohio, from July 13 to 15.
High wet-bulb temperatures are up to 100 times more likely due to climate change.
Climate influence:
Climate Shift Index (CSI) levels of 3 are forecast across the western and northern United States from July 13 to 15, meaning human-caused climate change made this extreme heat at least three times more likely. This signals a significant climate-influenced event.
From July 13 to July 15, more than 118 million people west of the Mississippi River will experience at least one day with a CSI level 3, indicating a very strong influence from climate change.
Temperatures made at least three times more likely by human-caused climate change are projected to affect approximately 695,000 square miles (1.8 million square kilometers) — about 23% of the area west of the Mississippi River.
Super Typhoon Bavi intensifies over climate-fueled ocean heat as marine heat waves grip every major ocean basin
Super Typhoon Bavi underwent extreme rapid intensification over exceptionally warm waters in the Pacific Ocean that were made up to 80 times more likely by climate change. The storm is expected to pass over ocean waters made 10 to 40 times more likely by climate change before impacting parts of Taiwan this weekend (July 10 -11) with winds as high as 290 kmh (130mph). The Pacific is experiencing a historic marine heat wave — but it’s far from alone. Every major ocean basin across the globe is currently experiencing unusually warm sea surface temperatures driven by climate change.
Pacific Ocean
The Pacific continues to host the world’s largest marine heat wave, now covering 58 million square kilometers —about 16% of Earth's oceans — an area larger than North and South America combined. A developing El Niño could be contributing additional warming in the eastern Pacific.
Climate change is driving the vast majority of this event: 85% of the marine heat wave area would not have occurred without human-caused warming.
Since January, approximately 91% of the Pacific has experienced marine heat wave conditions, with the most persistent hotspots in the North Pacific remaining in MHW conditions for more than 180 consecutive days.
Atlantic Ocean
Marine heat waves are less widespread across the Atlantic than in the Pacific or Mediterranean, with 18.8% of the basin currently affected. However, tropical sea surface temperatures remain in the upper 70s to upper 80s°F (24-32°C). Broad areas of the Atlantic are 2–5°F (1–3°C) above normal compared to the 1991-2020 climatology.
Climate change is driving nearly all of the existing marine heat wave area: 93.8% would not have occurred without human-caused warming.
Gulf of Mexico/Caribbean
Marine heat waves continue to dominate the Gulf of Mexico and the northwestern region of the Caribbean, with 46.4% of the region currently experiencing marine heat wave conditions. Of that area, 44.7% is attributable to climate change.
Sea surface temperatures are broadly in the 80s °F (27°C), with the hottest waters approaching 90°F (32°C) around Florida.
Mediterranean
The Mediterranean marine heat wave has intensified rapidly following repeated heat domes over Europe, with 78.6% of the basin now experiencing marine heat wave conditions.
Sea surface temperatures have climbed into the upper 70s to low 80s °F (24-28°C), while large areas of the western Mediterranean are running 5–9°F (3–5°C) above normal.
Climate change is driving nearly all of the event: 97.9% of the current marine heat wave area would not have occurred without human-caused warming.
Climate Matches of the Week: July 7-13
As the World Cup heads into the quarterfinals, the stakes are rising — and so are the temperatures. Several matches are forecast to be played in temperatures above 28°C (82.4°F), a threshold linked to declines in athletic performance.
GAMES TO WATCH
Norway vs. England
July 11 | 5 PM | Miami Stadium — Miami Gardens, FL
Forecast high: 87.3°F (30.7°C) — above 82.4°F (28°C) the athlete performance threshold
Climate Shift Index (CSI) — high: 3
High wet bulb temperature: 79.4°F (26.3°C) — above the dangerous humid heat threshold; event not possible without climate change influence
Climate change made this level of humid heat at least 100 times more likely.
Humidity is being fueled by exceptionally warm ocean waters off the coast of Miami, with sea surface temperatures in the upper 80s°F. Those ocean temperatures were made up to 500 times more likely by climate change.
Argentina vs. Egypt
July 7 | 12:00 PM | Atlanta Stadium *Climate Controlled* — Atlanta, GA
Forecast high: 92.4°F (33.6°C) — well above 82.4°F (28°C) the athlete performance threshold
Departure from normal: 5.9°F (3.3°C)
Climate Shift Index (CSI) — average: 4
Climate Shift Index (CSI) — high: 1
Other stadiums forecast to experience highs above the performance-impairing heat threshold include: Boston Stadium, Kansas City Stadium, and Los Angeles Stadium.
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To stay up to date, visit our World Cup Interactive Hub, where you'll find real-time weather forecasts for stadiums and individual matches. See whether your team will also be competing against the effects of climate change.
Climate change fuels extreme Fourth of July weekend heat wave across the U.S.
A dangerous heat wave will bring prolonged high temperatures, humidity, and warm overnight conditions to much of the eastern United States through the Fourth of July holiday (June 29–July 5). Human-caused climate change has significantly increased the likelihood and the intensity of this event, with the highest Climate Shift Index levels — CSI 5 — forecast across large parts of the country.
How unusual is the forecasted heat?
A significant heat wave, primarily impacting the eastern half of the United States, is the result of a strong, slow-moving high-pressure system, commonly known as a “heat dome,” that traps hot and dry air.
The National Weather Service forecasts multiple days of major to extreme heat risk for cities including Chicago, St. Louis, Nashville, Detroit, Pittsburgh, Cincinnati, Charlotte, Washington, D.C., Harrisburg, and New York City.
Temperatures are forecast to exceed 90°F to 100°F (35°C to 40°C) across parts of the eastern United States from June 29 through July 5, with some locations exceeding 100°F (37.8°C) — up to 20°F (11°C) above normal for late June/early July.
All-time high temperature records may be challenged in several cities, including Philadelphia and Washington, D.C.
The heat peaks on July 2, when 70% of the contiguous United States — about 239 million people — is forecast to have daytime highs above 90°F (32°C).
About 37 million people could see daytime highs above 100°F on July 3.
Overnight Heat:
260 million people are forecast to have overnight low temperatures that won’t drop below 70°F (21°C).
In some cities across Maryland, Delaware, New Jersey, and New York, overnight lows are forecast to remain above 80°F (26.7°C).
Hot summer nights limit people’s ability to cool off and recover from hot summer days. This can lead to greater heat stress and related health risks.
Humid Heat:
Humidity is helping to drive the persistent heat. Dangerous humid heat due to climate change will impact every state across the Eastern Seaboard from June 29 through July 5.
High wet-bulb temperatures are up to 100 times more likely due to climate change.
How has climate change influenced this heat?
Climate Shift Index (CSI) levels of 5 — the highest possible — are forecast across the eastern United States from June 29 through July 5, meaning human-caused climate change made this extreme heat at least five times more likely. This signals an exceptional climate-influenced event.
Climate Matches of the Week: June 30-July 6
Climate change is shaping week four of the World Cup, as extreme, climate change-driven heat spreads from Mexico all the way to Canada. Several matches are forecast to be played at temperatures above 28°C (82.4°F), a threshold associated with declines in athletic performance.
GAMES TO WATCH: June 30-July 6
Paraguay vs. Winner Match 77 (TBD)
July 4 | 5:00 PM | Philadelphia Stadium — Philadelphia, PA
Forecast high: 96.3°F (35.7°C); above 82.4°F (28°C) the athlete performance threshold
Departure from normal: 9.6°F (5.3°C)
Climate Shift Index (CSI): 2
Wet bulb temperature: 78.3°F (25.7°C); above the dangerous humid heat threshold; event not possible without climate change influence
Humid heat made at least seven times more likely due to climate change.
Argentina vs. Cape Verde
July 3 | 6:00 PM | Miami Stadium — Miami Gardens, FL
Forecast high: 86.6°F (30.3°C); above 82.4°F (28°C) the athlete performance threshold
Climate Shift Index (CSI): 1
Wet bulb temperature: 78.1°F (25.6°C); above the dangerous humid heat threshold; event not possible without climate change influence
Humid heat made at least 10 times more likely due to climate change.
Portugal vs. Croatia
July 2 | 7:00 PM | Toronto Stadium — Toronto, ON
Forecast high: 92.8°F (33.8°C); above 82.4°F (28°C) the athlete performance threshold
Departure from normal: 15.6°F (8.7°C)
Climate Shift Index (CSI): 2
Wet bulb temperature: 79.4°F (26.3°C); above the dangerous humid heat threshold
Humid heat made at least seven times more likely due to climate change.
Other stadiums forecast to experience highs above the performance-impairing heat threshold include:
Atlanta Stadium, Houston Stadium, Dallas Stadium, Kansas City Stadium, Los Angeles Stadium, New York New Jersey Stadium.
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To stay up to date, visit our World Cup Interactive Hub, where you'll find real-time weather forecasts for stadiums and individual matches. See whether your team will also be competing against the effects of climate change.
Climate change is driving extreme heat and humidity for the Colombia vs. Portugal World Cup match in Miami
On Saturday, June 27, the Colombia vs. Portugal World Cup match at Miami Stadium is forecast to experience climate change-driven extreme heat and humidity.
On Saturday, June 27, the Colombia vs. Portugal World Cup match at Miami Stadium is forecast to experience climate change-driven extreme heat and humidity.
Forecast daily highs are expected to reach the low 90s°F (low 30s°C), which is above the performance-impairing heat threshold.
By the 7:30 p.m. ET kickoff, temperatures are not expected to have fallen significantly and are forecast to remain around 87°F (30.5°C).
These high temperatures are made two times as likely by climate change.
The stadium is also forecast to experience dangerous humid heat due to climate change. The daily high wet-bulb temperature is forecast to reach 78°F (25.6°C).
This intense humidity is being fueled by very warm ocean temperatures off the coast of Miami. Ocean temperatures are up to 86.7°F (30.4°C), which is 3°F (1.7°C) warmer than normal and made up to 200 times more likely by climate change.
There is also a chance of thunderstorms from late afternoon through 8 p.m. ET, which have the potential to delay the match.
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Explore Climate Central’s information hub, Off Your Game: How Climate Change Could Slow Down the 2026 World Cup, to find climate data and stories for every stadium, match, and team. Check in throughout the World Cup for regular heat updates.
Climate change is driving extreme heat for the DR Congo vs. Uzbekistan World Cup match in Atlanta
On Saturday, June 27, the DR Congo vs. Uzbekistan World Cup match at Atlanta Stadium is forecast to experience climate change-driven extreme heat. While the Atlanta stadium is fully climate-controlled, the fan fest is held outdoors in Centennial Olympic Park, so workers and fans will be exposed to the heat.
On Saturday, June 27, the DR Congo vs. Uzbekistan World Cup match at Atlanta Stadium is forecast to experience climate change-driven extreme heat.
While the Atlanta stadium is fully climate-controlled, the fan fest is held outdoors in Centennial Olympic Park, so workers and fans will be exposed to the heat.
Forecast daily highs are expected to reach 93.3°F (34°C), which is above the performance-impairing heat threshold.
By the 7:30 p.m. ET kickoff, temperatures are not expected to have fallen significantly and are forecast to remain around 89°F (31°C).
These high temperatures are 6.5°F (3.6°C) above average and made more likely by climate change.
The heat index, which is calculated by combining the air temperature and humidity, is forecast to reach 97°F (36.1°C).
The forecast daily high wet-bulb temperature is 73.4°F (23°C).
Sign up to receive weekly updates from Climate Central during the 2026 World Cup.
Explore Climate Central’s information hub, Off Your Game: How Climate Change Could Slow Down the 2026 World Cup, to find climate data and stories for every stadium, match, and team. Check in throughout the World Cup for regular heat updates.