Heat and cold waves are extreme temperature events with a high potential of causing negative impacts on human health, and natural and socioeconomic systems, depending on their duration and intensity. There is, however, no consensual approach to address their definition, which is critical to set priority action areas to prevent such risks. Mainland Spain experiences heat and cold waves every year with important impacts especially in the most populated areas with mild or transition climates. Here we used a high-resolution (5 × 5 km) gridded daily temperature dataset and employed a combination of threshold exceedances of maximum and minimum temperature in the same day to identify heat and cold wave events over 75 years (1940–2014). We further examined the duration and the seasonal/annual intensities to detect potential spatial and temporal patterns. Additionally, we used the days within the most widespread events to perform a synoptic classification to categorise the atmospheric conditions leading to high-risk situations. Our results show a similar historical duration of heat and cold waves (4–5 days) and a much higher seasonal intensity of cold ones (double than heat waves). We find a tipping point in the early 1980s from which heat waves became more frequent, longer, and more intense than cold waves. Finally, we discern between 9 historical weather types with a dominance of southern advections driving heat waves and cold continental north-northeast air masses causing cold waves. Understanding the patterns and trends of heat and cold waves, as well as the mechanisms of their genesis is key to assist in risk management in mainland Spain, especially in the context of a warming climate scenario.

热浪和冷浪是极端温度事件，极有可能对人类健康、自然和社会经济系统造成负面影响，具体取决于其持续时间和强度。然而，没有达成共识的方法来解决它们的定义，这对于确定优先行动领域以防止此类风险至关重要。西班牙大陆每年都会经历热浪和冷浪，产生重要影响，尤其是在气候温和或过渡气候的人口最多的地区。在这里，我们使用高分辨率（5 × 5 km）网格化每日温度数据集，并结合同一天的最高和最低温度阈值超过来识别 75 年（1940-2014 年）的热浪和冷浪事件。我们进一步检查了持续时间和季节性/年度强度，以检测潜在的空间和时间模式。此外，我们使用最广泛事件中的日子进行天气分类，以对导致高风险情况的大气条件进行分类。我们的结果显示，热浪和冷浪的历史持续时间相似（4-5 天），而冷浪的季节性强度要高得多（是热浪的两倍）。我们在 1980 年代初发现了一个转折点，从那时起，热浪变得比冷浪更频繁、更长、更强烈。最后，我们区分了 9 种历史天气类型，其中主要是南部平流驱动热浪和寒冷的大陆北-东北气团导致冷浪。了解热浪和冷浪的模式和趋势，以及它们的成因机制是协助西班牙大陆风险管理的关键，