Mexico's Caribbean reefs' three worst heat years were 2023–2025

Claim types Estimate

Estimate. NOAA Coral Reef Watch, CoralTemp v3.1 regional virtual stations, station 'Quintana Roo, Mexico': daily satellite sea surface temperature turned by NOAA into degree heating weeks (DHW), the heat of days at least 1 °C above the usual summer maximum, added up over the past 12 weeks, in °C-weeks. Each station summarises the 90th-percentile pixel of its reef region; NOAA labels the product experimental. The yearly peak (highest daily DHW in each complete calendar year, 1986–2025) is a progrss calculation from NOAA's daily station file, held in the progrss vault (noaa-crw; recorded recomputes from NOAA's live files match). Peaks: 21.43 in 2023, 19.83 in 2024, 17.79 in 2025; the highest before 2023 was 14.68 in 2020, and the highest before 2015 was 7.77 in 2005. Years at 8 or more: 2015, 2016, 2017, 2019, 2020, 2023, 2024, 2025. 8 degree heating weeks is the start of NOAA's Bleaching Alert Level 2, where NOAA says severe, widespread bleaching is likely; 20 or more is its highest level, Alert Level 5. Same-method control: across all 214 NOAA regional stations, 23 have 2023, 2024 and 2025 as their three highest years (progrss count from the same yearly peaks), so the pattern is not unique to Mexico but is far from universal. 2026 is not shown because the year is not complete. Heat stress is what satellites see at the sea surface, not a survey of the reef: it says bleaching was likely, not how much coral bleached or died. Stripe strength runs from the series' lowest year (0) to its highest; the three yellow stripes are the three highest years. No cause is claimed beyond what is measured. Licence: NOAA data are in the public domain.