Comprehensive reports from the National Oceanic and Atmospheric Administration (NOAA) and the National Weather Service (NWS) in San Juan, Puerto Rico, highlighted extreme weather events in 2024. NOAA revealed that 2024 was the warmest year globally since record-keeping began in 1850.
The NOAA climate report provided detailed information about weather across numerous regions of Earth. The document began with sharing the following highlights about notable climate-related events that occurred during 2024:
- “NOAA ranks 2024 as the warmest year in its global temperature record, which dates back to 1850.
- Upper ocean heat content—the amount of heat stored in the top 2000 meters of the ocean—was at a record high in 2024.
- Antarctic sea ice extent was second lowest on record in both February (when the annual minimum occurs) and September (when the annual maximum occurs).”
The NOAA report explained the following information about global temperatures.
“In 2024, the global surface temperature was 2.32°F [Fahrenheit] (1.29°C [Celsius]) above the 20th century average. This ranks as the highest global temperature in the period of 1850 [to] 2024, beating the next warmest year (2023) by 0.18°F (0.10°C). The 10 warmest years since 1850 have all occurred in the past decade, [and] in 2024, global temperature exceeded the pre-industrial (1850 [to] 1900) average by 2.63°F (1.46°C).”
The article also noted that the world’s oceans were anomalously warm in 2024.
“Much of the ocean surface was warmer than average as well,” NOAA explained. “The largest warm temperature anomalies were in the North Atlantic and the western North Pacific,” NOAA said. “Overall, it was the warmest year on record for the ocean surface,” NOAA added.
U.S. Virgin Islands and Puerto Rico Climate Impacts
NOAA went on to say that 85 named tropical cyclones occurred across the globe in 2024, slightly below the climatological normal of 88 cyclones occurring worldwide. However, the North Atlantic (which includes the mainland of the United States) saw an above-average hurricane season.
“The North Atlantic had 18 named storms, which was above the 1991 [to] 2020 average of 14,” NOAA explained. “11 of those [tropical cyclones] were hurricanes, including five major hurricanes,” NOAA said. “The Accumulated Cyclone Energy was about 32 percent above normal, [and] most of the damage in the U.S. was attributable to two major hurricanes: Helene in September and Milton in October,” the report said.
A second report, published by the NWS in San Juan, Puerto Rico, provided further details about the extreme weather events across Puerto Rico and the U.S. Virgin Islands. Exceptionally warm land and ocean temperatures were a significant finding in the NWS report.
The NWS update provided the following “Key Points” regarding significant weather events around the local area in 2024:
- “The year 2024 ended as the warmest on record for the San Juan area climate site.
- A total of 131 daily warmest minimum records were set or tied.
- Saint Croix ended with the warmest January, March, and winter season on record.
- The San Juan area climate site reached temperatures at or above 90°F for 182 days.
- There were 50 consecutive days with highs at 90°F or higher.
- The Caribbean Coastal Ocean Observing System nearshore buoys network observed warmer-than-normal water temperature anomalies.
- Tropical Storm Ernesto became a hurricane while moving just north of Puerto Rico. The storm brought flooding, mudslides, and gusty winds across the local islands.
- After a dry start, drought [across both U.S. territories] dissipated during spring, and several rainfall episodes were observed throughout the year.
- Most climate sites ended up wetter than normal, with some sites in the Virgin Islands and eastern and interior Puerto Rico having a surplus of 16 to more than 20 inches of rainfall.
- Lightning incidents were also noticeable this year, with at least eight documented events.
- The majority of weather-related fatalities were attributed to rip currents.”
Other extraordinary events cited in the NWS report revealed that a tornado touched down in Arecibo, Puerto Rico, on May 2, 2024, and several wildfires affected southern and western Puerto Rico toward the beginning of 2024.
A Local Meteorologist’s Perspective
The Source contacted Emanuel Rodriguez, a senior service hydrologist with the NWS in San Juan, Puerto Rico, for more insight on noteworthy weather events across the U.S.V.I. and Puerto Rico during 2024. Rodriguez is among the climate experts who publish the NWS yearly report.
When asked about weather-related events that were particularly surprising, Rodriguez said that the level of heat across the region was especially fascinating.
Exceptionally Warm Air Temperatures
“The [most significant weather] event that kept surprising us was the heat, even more than Tropical Storm Ernesto,” Rodriguez said. “Day after day, new heat records were set across our main climate site [located in San Juan] and also across our Cooperative Observer Program stations,” he continued.
“We had the longest streak of days above 90 degrees [Fahrenheit] at the San Juan International Airport, and many nights with lows above 80 degrees,” Rodriguez stated. “This, of course, triggered the issuance of several heat advisories and excessive heat warnings,” he noted.
“Some [of the] lessons learned about [the extreme heat and issuing alerts are] that we [will now be] looking for ways to tie our [alerts and advisories] to [the potential] impacts to the population, rather than [issuing alerts that are solely] being based on a certain meteorological threshold,” Rodriguez said. “It is not an easy task, but we believe it will help the citizens to better prepare for extremely hot spells rather than having a heat advisory out every single day during the summer months,” he added.
The NWS report noted that, “The year [of] 2024 will be remembered as the warmest year in the San Juan area climate site, with an average temperature of 83.3°F, surpassing the previous record of 82.3°F set in 1983.”
Regarding the U.S. Virgin Islands, Rodriguez explained that several days of temperature data were unavailable across the U.S.V.I. However, he confirmed that heat was still very intense across the U.S.V.I. and around the entire Caribbean.
“Unfortunately, the climate [testing] sites in the Virgin Islands had days with no temperature reports, so we could not calculate the yearly temperature average there,” Rodriguez said. “Nevertheless, the heat was evident across all the Caribbean Islands, with impacts to agriculture, water resources, power demand, and health,” he continued.
The NWS report explained the following about some of the temperature data that was learned across the USVI:
“The heat was no exception across the Virgin Islands. Even though some data was missing during spring in early summer, temperatures and heat indices were still above normal across the islands.
“At the end of the year, Saint Croix ended with the warmest winter (December 2023 [to] February 2024) on record, with an average temperature of 80.8°F. It also registered the fourth warmest summer (June [to] August; 85.3°F) and fall (September [to] November; 83.8°F).”
Sea Surface Temperatures
Rodriguez elaborated on the NOAA and NWS findings that indicated above-average sea-surface temperatures.
“Since late April 2023, the Atlantic Ocean entered into a marine heat wave phase, meaning that the waters were well, well above normal,” Rodriguez stated. “Our [local] island [air] temperatures are regulated by the waters around the islands,” he said.
“[However, because] the water [temperatures have been] almost as warm as the land, [the air temperature across the islands] has not been able to cool down during the night hours. Hence temperatures will quickly rise during the day,” Rodriguez noted. “Additionally, with warmer waters, there are also higher humidity levels,” he said. “So, the heat indices are also higher than normal, making outdoor activities very uncomfortable and potentially dangerous for people that spend too much time outside.”
Above-Average Precipitation and Tropical Storm Ernesto
The NWS reported that plentiful rainfall occurred throughout the year across Puerto Rico and the U.S. Virgin Islands, ending drought conditions across both territories around May 2024.
The report explained the following information about record-setting precipitation:
“By the end of the year, the San Juan area climate site collected almost 80 inches of rainfall, ending as the eighth wettest on record. Many municipalities from the east, interior, and west collected over 100 inches of rainfall. The extreme south of Puerto Rico saw the least rainfall, with amounts ranging from 40 [to] 60 inches. The precipitation total across the Virgin Islands ranged from 55 to 75 inches, which is wetter than normal. All of the islands ended up wetter than normal, with a greater surplus of rainfall observed across western and eastern Puerto Rico (more than 60 inches).”
Tropical Storm Ernesto, which passed across the area in August, was one of the systems that generated significant rainfall. When asked about lessons learned after Ernesto, Rodriguez explained that preparation is crucial.
“[Tropical Storm Ernesto was] an example of why we should focus on impacts [to residents and visitors across the islands] rather than [focusing too much] on meteorological terms,” Rodriguez said. “The main impacts related to Ernesto were going to be the heavy rainfall and potential for flooding and mudslides, hazardous marine conditions, and gusty winds, so people [needed to prepare] accordingly for [those storm-related impacts],” Rodriguez said. “[Additionally,] with [ocean] water [temperatures being much] warmer than normal, and other atmospheric factors, rapid intensification is another [scenario that] we have to consider in the future,” he acknowledged.
“[Ultimately,] it’s important that people prepare for hurricane season well in advance [and be ready for cyclones] by the beginning of the hurricane season,” Rodriguez advised. “If we leave [preparations] to the very last minute, [by the time we are under a [cyclone] Watch [or] Warning, it might be too late to get provisions.”
Looking Ahead
NOAA recently reported that a La Niña weather pattern has emerged and is expected to last until about April.
During a La Niña cycle, the ocean waters across the equatorial Pacific Ocean cool significantly, affecting global weather. During La Niña, wind shear—a change in wind direction and velocity with height in the atmosphere—also typically decreases in the Atlantic Ocean. A reduction in wind shear can favor cyclone development. This pattern is the opposite of El Niño, a warming of the equatorial Pacific, which usually increases wind shear in the Atlantic Ocean, helping to rip apart storms and prevent hurricane formation and intensification.
“Scientists call [the two opposing climate patterns of El Niño and La Niña] the “El Niño-Southern Oscillation” (ENSO) cycle. El Niño and La Niña can both have global impacts on weather, wildfires, ecosystems, and economies,” according to NOAA.
Rodriguez offered the following additional information about this event, and how it may affect weather across the local islands.
“[The current] La Niña is weak, and it’s not expected to last long, so by the time the 2025 hurricane season gets here, it will likely be gone,” Rodriguez stated. “However, [an] ENSO-neutral [weather pattern] has also resulted in our islands being hit by past tropical cyclones,” he said. “Nevertheless, it only takes one storm to make a season memorable, regardless of how active or inactive a season might be, [and the advice from the NWS is] to be always ready, regardless of the seasonal forecast.”
Rodriguez predicted that the region could expect 2025 to be another year of very warm temperatures through 2025, acknowledging that the forecast can still change.
“The climate [computer models] are still suggesting that temperatures will be above normal this year, [with] a greater than 70 percent chance [of above-average temperatures] through May 2025 and 50-60 percent chance after that,” Rodriguez said. “There’s a chance that the [aforementioned] marine heat wave will weaken or finally dissipate this year, but we’ll have to wait and see,” he said. “This is a field [within the climate space] that climatologists and oceanographers are still understanding, so we don’t have all the answers yet,” Rodriguez concluded.
Weather Forecast Information
Weather forecast information, including severe weather alerts, is available from the VITEMA website and the National Weather Service.
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