Trellis Talks: Understanding Napa’s Unusual Growing Season with Daniel Swain

In this episode of Grown in Napa Valley, Executive Director Caleb Mosley sits down with climate scientist Daniel Swain to discuss the unusual 2026 growing season and what Napa Valley growers should be paying attention to. Swain explains the record-breaking heat experienced in March and April, the complex relationship between climate change and extreme weather events, and why growers are increasingly dealing with both ends of the spectrum: severe drought conditions and periods of excessive rainfall. The conversation also explores topics such as offshore winds, fog, vapor pressure deficit, wildfire risk, and how a warming climate is changing the challenges facing agriculture across California. 
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The discussion then turns to the developing El Niño, which Swain believes is highly likely to strengthen through the summer and could become one of the more significant El Niño events on record. He outlines the potential implications for California, including an increased likelihood of a wet winter, possible early-season rainfall events, and greater weather variability throughout the remainder of the year. Swain emphasizes that while climate change presents real risks, it also creates opportunities for California agriculture to rethink water management through groundwater recharge, floodplain restoration, and capturing excess winter runoff. The episode highlights the importance of adaptation, preparedness, and long-term planning as growers navigate an increasingly dynamic and unpredictable climate future.