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Concurrent with the background rise in global mean temperatures, changes in extreme events are also becoming evident, and are arguably more impactful on society. This research examines trends in three components of seasonallyrelative extreme temperature and humidity events in North America that directly influence human thermal comfort: event frequency, duration, and areal extent. Results indicate that for the majority of the study domain, changes in these events are in the expected direction with changes in means. Extreme heat events are generally increasing throughout the domain, with the largest changes in summer and autumn in the eastern portion of Canada and the United States. Cold events are largely decreasing in these same locations and seasons, with additional widespread decreases in winter. Interestingly, significant increases in cold events are also evident in autumn in parts of the western United States. Extreme humidity events are showing an even greater change than temperature eventsnearly all of Canada and most of the United States is seeing significant increases in extreme humid events and decreases in dry events, while the southwestern deserts show widespread significant increases in dry events, especially in winter and spring. Changes in event duration and spatial extent mimic these results. Importantly, this research demonstrates that there are regions that show changes to extreme events that differ from the overall changes in means, highlighting the importance of looking beyond climate averages to examine not only extreme events, but changes in higher-order statistical moments. K E Y W O R D S climate change, extreme events, North America, statistical moments, trends 1 | INTRODUCTION The evaluation of climate changes, both observed and projected, has most frequently focused on the analysis of mean fields (e.g., IPCC report, Hartmann et al., 2013). Considering their relative infrequency, however, extreme weather events have a disproportionately greater impact on many biological systems (e.g., human health, agriculture, ecosystems) in comparison to climatic averages, yet are less-often studied and deserve more detailed analyses.

Biological invasions are usually examined in the context of their impacts on native species. However, few studies have examined the dynamics between invaders when multiple exotic species successfully coexist in a novel environment. Yet, long‐term coexistence of now established exotic species has been observed in North American lady beetle communities. Exotic lady beetles Harmonia axyridis and Coccinella septempunctata were introduced for biological control in agricultural systems and have since become dominant species within these communities. In this study, we investigated coexistence via spatial and temporal niche partitioning among H. axyridis and C. septempunctata using a 31‐year data set from southwestern Michigan, USA. We found evidence of long‐term coexistence through a combination of small‐scale environmental, habitat, and seasonal mechanisms. Across years, H. axyridis and C. septempunctata experienced patterns of cyclical dominance likely related to yearly variation in temperature and precipitation. Within years, populations of C. septempunctata peaked early in the growing season at 550 degree days, while H. axyridis populations grew in the season until 1250 degree days and continued to have high activity after this point. C. septempunctata was generally most abundant in herbaceous crops, whereas H. axyridis did not display strong habitat preferences. These findings suggest that within this region H. axyridis has broader habitat and abiotic environmental preferences, whereas C. septempunctata thrives under more specific ecological conditions. These ecological differences have contributed to the continued coexistence of these two invaders. Understanding the mechanisms that allow for the coexistence of dominant exotic species contributes to native biodiversity conservation management of invaded ecosystems.