Global temperature anomalies, June 2023. This image shows the average land and sea surface temperatures in June 2023, compared to the 1951-1980 average for the same month. Areas that are hotter than normal are red, those that are cooler are blue. June 2023 was the hottest June since modern record-keeping began in 1880. This continues a long-term warming trend that has seen the past nine years being the warmest of the past 140 years. Scientists attribute this warming to increased carbon dioxide and other greenhouse gases in the atmosphere due to human activity.