☀️ UK Records Hottest and Sunniest Year Ever

💨 The Climatology of Derecho Events

A recent study from the Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada analyzed the climatology of 1995-2024 United States warm-season derecho events and the potential associated climate forcing. They identified 147 warm-season derechos during the 30 year time frame, resulting in an average of 5 derechos per warm season. The frequency of derecho-producing convection has increased over the past 30 years, most notably during the last 10 years. The number of high-end derechos occurring each year has also increased with time. A poleward shift in derecho paths as the warm season progresses was noted as spatial trends were analyzed. The study also found that the most notable climate-forcing association is Nino-4 sea-surface temperature anomalies with warming in the central Pacific.

Kacie Nicole Shourd and Michael L. Kaplan, E-Journal of Severe Storms Meteorology

🌊 NOAA Upgrades SST Datasets with AI

Since 1850, NOAA has been measuring changes in sea surface temperatures (SST), studying the impacts of temperature fluctuations on the ocean ecosystem. These measurements began in the late 18th century with sailors collecting samples of sea water in wooden buckets to measure SSTs. Today, SSTs are collected by a variety of platforms including ships, buoys, and Argo floats. These measurements are then integrated into NOAA’s Extended Reconstructed Sea Surface Temperature (ERSST) dataset to study long-term changes in SST and are widely used in ocean research, weather forecasting, and other environmental applications. The latest version of ERSST has recently been upgraded by implementing an interpolation method using artificial intelligence to fill in missing data points, creating a more complete picture of global SSTs. ERSSTv6 now has a higher spatial coherence and lower error in the global oceans from 1850 to 2021 compared to ERSSTv5. These improvements are more pronounced in the tropical Pacific and the Southern Hemisphere oceans between 60S and 30S. This upgrade will also be a valuable tool for El Nino and La Nina monitoring and forecasting.

National Centers for Environmental Information, NOAA

☀️ UK Records Hottest and Sunniest Year Ever

The Met Office announced the United Kingdom just experienced its hottest and sunniest year ever in 2025. The average annual temperature was 10.09C (50.16F), topping the previous hottest year on record in 2022 with an average of 10.03C. 2025 also marks only the second time on record that the annual mean temperature exceeded 10C since records began in 1884. Four of the last five years are now in the top five warmest years since 1884, an indication of just how fast the climate is changing. All of the top-10 warmest years have occurred in the last two decades.

Reuters

Our Top Newsletters from 2025

Just before the end of the year, we hit a big milestone - 100 ClimateWatch newsletters published! To celebrate, we thought we’d share our top newsletters from 2025:

1. 🥤 Climate Change Increases Sugar Intake

2. 🤖 Is AI Helping or Hurting Climate Change Efforts?

3. 🌪️ U.S. Billion Dollar-Disasters in 2025

4. ☔️ AccuWeather Rainfall Climate Analysis

5. 🌊 La Niña Conditions Are Present