The increased occurrence of hot, dry, and windy weather is resulting in worsening fire conditions with five of the worst fire seasons on record in British Columbia occurring since 2017. Two critical daily periods have implications for fire growth: peak burn and overnight conditions. This study aims to provide insights into changing conditions during peak burn and overnight weather by investigating trends in hourly weather variables (temperature, relative humidity, and windspeed) and associated fire weather indices (Fine Fuel Moisture Code, Initial Spread Index, and Fire Weather Index) across different Biogeoclimatic Ecosystem Classification (BEC) zones in British Columbia. Historical weather data from June, July, August, and September spanning two periods, 1990-2005 and 2006-2021 was analyzed at an hourly scale. The analysis revealed the greatest magnitude of change occurred in the afternoon hours for all zones and months in the study. Spread event conditions are occurring more frequently and BEC zones affected by the rain shadow effect are seeing more significant results indicating warming and drying. This analysis of hourly weather highlights the implications of observed trends on expected changes in fire behaviour with a spatial and
temporal lens and can be used to inform wildfire management practices across British Columbia.
