Executive Summary

Winters are warming, heavy rainfall is becoming more common, and climate impacts are reaching across the natural, social, and economic systems that sustain Vermont. The Vermont Climate Assessment (VCA) 2025 brings these changes into focus, showing what has changed, what is changing now, and what the impacts mean for Vermonters.  

VCA 2025 is designed to help Vermonters make informed decisions in a changing climate. Nearly 200 experts and practitioners from government, universities, nonprofits, and private industry contributed to the assessment, bringing together knowledge from across the state and across disciplines (see Process 1.2). 

The assessment traces how Vermont’s climate has changed since 1900, with a closer look at recent trends through 2024 in temperature, precipitation, and extreme events across the state and its three National Weather Service (NWS) climate divisions. The chapters that follow explore how a changing climate is reshaping the places, resources, and activities that matter to Vermonters: forests, water, fish and wildlife, agriculture and food systems, infrastructure, energy, outdoor recreation and tourism, human health, and communities. 

VCA 2025 is the third statewide climate assessment, following assessments published in 2014 and 2021. Across all three, the direction of climate change is consistent. What has changed is the scale and acceleration of the impacts. VCA 2025 shows that climate impacts are becoming more widespread and interconnected, affecting Vermont’s environment, economy, and quality of life. 

Multiple extreme weather events, including the July 2023 and 2024 floods and summer 2025 drought, have disrupted the lives and livelihoods of Vermonters over the past half decade. Of the 19 “Billion-Dollar Weather and Climate Disasters” events that have impacted Vermont since 1980, four of those have been since 2022 (NOAA NCEI, 2025). Extreme weather events are expected to continue as heavy precipitation days (24-hour periods with >1 inch of rainfall) have occurred 40% more often since 1900 (see Climate Change in Vermont 2.5). Heavy precipitation events can quickly overwhelm waterways and damage infrastructure, especially since 75% of surveyed rivers in Vermont cannot access their historical floodplains. These rivers instead remain confined to channels thereby increasing erosion potential and flood damages downstream. Vermont streams experienced nine more days of high streamflow conditions (>70^th percentile) when comparing the 1966–1995 period to the 1996–2025 period for 68% of monitored streams across the state. Following flood disasters in July 2023 and 2024, many rivers established new record stage heights including the Winooski, Missisquoi, Passumpsic, Dog, and Black rivers (see Water Resources 4.4). 

Flooding impacts homes and towns, processing facilities, and distribution networks across the state. In July 2023, 23 wastewater treatment plants were damaged resulting in tens of millions of dollars in repair costs and hundreds of thousands of gallons of untreated sewage entering waterways (see Infrastructure 7.5). Vermont has 69 high hazard dams and 190 dams that are greater than 100-years old; these dams are at greater risk of overtopping or reaching catastrophic failure during flood events (see Infrastructure 7.6). Vermonters reported over 8,000 instances of significant damage to their homes following flood events in 2023 and 2024 with additional damages to businesses and farmers (see Infrastructure 7.4). On average, farmers reported losing 28% of their annual income in 2023 and 25% in 2024 due to extreme weather disasters (see Agriculture and Food Systems 6.5), and over 1,000 businesses reported significant flood damages in 2023 and 2024 (see Infrastructure 7.4). Such climate-related losses and disruptions ripple beyond individual farms and businesses and threaten economic and food security for many Vermonters.  

As the share of total precipitation in Vermont shifts towards extreme storm events, Vermonters will experience more dry spells between storms that can lead to drought. The summer 2025 drought was the most severe incidence since 2000 and affected the entire state (see Climate Change in Vermont 2.6). Drought conditions reduce hydroelectricity generation and increase reliance on fossil fuel sources, further exacerbating climate change impacts (see Energy 8.4). Following Vermont’s 2025 drought, 31% of farmers reported loss of feed crops and 52% reported feed shortages requiring farmers to purchase more feed to retain healthy livestock (see Agriculture and Food Systems 6.4). Drought occurrence will reduce plant species’ ability to survive and thrive in Vermont. Northern hardwood-dominated forests may experience a shift in species composition towards more drought-tolerant and heat-tolerant tree species currently present in the mid-Atlantic or southern New England regions, such as oaks and hickories (see Forests 3.5). 

Annual average temperatures increased by +3.6ºF since 1900, with Southeastern Vermont warming the most (4.9ºF). Further, the rate of warming is increasing: annual temperatures increased 0.3ºF/decade in the last 65 years and then almost tripled in the last 35 years (0.8ºF/decade; see Climate Change in Vermont 2.4 and 2.10). As temperatures rise, species adapted to warmer conditions are expected to fare well, while cold-adapted trees and wildlife (e.g., red spruce, white cedar, Bicknell’s thrush, spruce grouse, Canada lynx) face declines and potential local extinctions (see Forests 3.5 and Fish and Wildlife 5.3). Changes in species ranges, combined with habitat loss and other climate change impacts, have increased the “at-risk” species in Vermont by 33%. Shifting habitats alter species interactions and thus disease dynamics, putting animal and human populations at risk. Tick- and mosquito-borne diseases are increasing in rate and number as changing temperatures lengthen their active season (see Fish and Wildlife 5.4). Rates of Lyme disease increased about four-fold between 2008–2024 and new diseases may emerge, like Jamestown Canyon Virus, first detected in Vermont in 2025 (see Human Health 10.6). Many pests or diseases that cause tree mortality, like beech leaf disease, butternut canker, emerald ash borer, hemlock wooly adelgid, and spotted lanternfly are already established in Vermont (or have the potential to rapidly emerge) and are expected to expand with climate change (See Forests 3.7 and Fish and Wildlife 5.4).  

Vermont’s average annual precipitation increased by 7.3 inches (185 mm) since 1900 (see Climate Change in Vermont 2.5). Median annual streamflow increased an average of 19% when comparing the 1966–1995 period to the 1996–2025 period across almost all of Vermont’s streams, largely due to increases in flows during winter (December, January, and February) and summer (June, July, and August; see Water Resources 4.3). Warmer and wetter conditions reduce the number of working days for forest managers, operators, and loggers and can delay planting and harvesting due to over-saturated soils (see Forests 3.8).  

Vermont’s average annual precipitation has increased by 7.3 inches (185 mm) since 1900. Analysis of U.S. Geological Survey stream gauge records comparing median annual streamflow between 1966–1995 and 1996–2025 shows that streamflow has increased an average of 19% across almost all of Vermont’s streams, largely due to increases in flows during winter (December, January, and February) and summer (June, July, and August). Warmer and wetter conditions are reducing the number of working days for forest managers, operators, and loggers; and delaying planting and harvesting due to over-saturated soil. Models also show Vermont’s road surfaces will deteriorate more quickly compared to the national average due to increased heat and precipitation severity.   

Vermont’s seasons are changing, with effects across the state’s economy, culture, and way of life. Winters are warming faster than all other seasons (+4.6°F since 1900), causing more winter precipitation to fall as rain compared to snow. Today, Vermonters living in the Southeastern climate division experience almost 32 inches less snowfall compared to the 1960s. Declining trends in snowfall are accelerating: annual snowfall decreased by 4.9 inches/decade in the last 65 years and 8.4 inches/decade in the last 35 years, almost doubling (see Climate Change in Vermont 2.5 and 2.10). Winter warming increased the average surface temperature of Lake Champlain by 6.8°F since 1964, with the greatest temperature changes in South Lake A and Malletts Bay. Lake Champlain completely freezes over much less frequently, approximately once every five years compared to annually (see Water Resources 4.5). These changes disrupt wildlife (see Fish and Wildlife 5.5) and limit access to winter activities like ice fishing, ice skating, and snowmobiling. Other winter snow sports (like downhill skiing) are also impacted by warmer winters, and particularly warmer winter nights, though many ski operators are adapting through snowmaking, snowfarming (i.e., using insulated piles of preserved snow), and boosting revenue by offering year-round activities (see Outdoor Recreation and Tourism 9.3).  

The growing season (defined here as the freeze-free period) has lengthened by almost 24 days since 1900 and trends are accelerating: the growing season increased by 3.3 days/decade in the last 65 years and 4.5 days/decade in the last 35 years (see Climate Change in Vermont 2.4). The growing season length is increasing due to both the last spring freeze occurring almost a week earlier and the first fall freeze occurring almost two weeks later since 1900 (see Agriculture and Food Systems 6.3). Despite consistent lengthening of the growing season, variability from year to year remains high, which creates uncertainty for farmers and maple producers. Vermont maple trees have later fall peak leaf color and leaf drop and earlier spring budbreak and leaf emergence, which have consequences for tourism and the maple sugar industry (see Forests 3.5 and Outdoor Recreation and Tourism 9.6). A lengthening growing season will also shift harvest and planting dates and may increase productivity and viability of some crops in Vermont. However, hazards, such as heat, drought, and invasive insect and pathogen outbreaks associated with longer growing seasons can cause an overall decline in tree growth rates and crop success (see Agriculture and Food Systems 6.4 and Forests 3.5). 

Vermonters are experiencing more frequent extreme heat events, often exacerbated by rising humidity. Warm nights (i.e., when minimum temperature >70ºF) have increased by 0.52 days/decade since 1990 or two days total since 1900, while extremely hot days (i.e., when maximum temperature >90ºF) have increased by 0.81 days/decade since 1990 or 3.6 days total since 1900. Extreme heat is felt most intensely in the Southeastern climate division, which has averaged 15 days/year of extremely hot days since 2020. Concurrently, absolute humidity has exceeded the long-term average since 1990 (see Climate Change in Vermont 2.4). 

Longer and hotter summers put Vermonters at risk, as only 67% of the state has access to air conditioning. Rising temperatures are linked with increased emergency department visits especially during heat waves (three or more consecutive days above 90°F), which are increasing in frequency and severity (3x increase since 2020 in Burlington, VT; see Human Health 10.3). Residents and tourists may want to seek refuge from the heat by participating in water-based activities like boating, swimming, and paddling; however, outdoor recreators should be cautious of extreme heat and heat stress, harmful algal blooms, unsafe natural swimming areas following heavy rainfall, and reduced air quality from pollen and wildfire smoke (see Outdoor Recreation and Tourism 9.5).  

Heat affects more than human health.  Extreme heat increases heat stress for livestock, thereby negatively impacting milk and meat production, and increases disease pressures that threaten animal health and productivity (see Agriculture and Food Systems 6.4). Models show Vermont’s road surfaces will deteriorate more quickly compared to the national average due to increased heat and precipitation severity (see Infrastructure 7.3).  

Climate change is reshaping Vermont’s water resources, including how much water is available and how clean it is. Floods transport large amounts of sediment, nutrients, and debris over land and to downstream waters. Following flooding in July 2023, Lake Champlain had reduced water clarity for two weeks, impacting plant photosynthesis and wildlife predation. Increased winter flooding from rain-on-snow, winter rain, and/or mid-season snowmelt is generating polluted run-off during a time when plants are still dormant and unable to uptake excess nutrients, often increasing the likelihood of harmful algal blooms during the summer months. Winter runoff from midseason melt events contributed 30–65% of the annual nitrogen load and 15–55% of the annual phosphorus load in Lake Champlain. Lake Morey, Lake Carmi, and Missisquoi Bay all increasingly experience harmful algal blooms, which negatively affects plants, wildlife, outdoor recreators, and businesses (see Water Resources 4.5) Finally, between heavy periods of precipitation, there may be extended periods of drought that decrease groundwater recharge, such as occurred in summer 2025 and affected over 600 private well owners (see Water Resources 4.3). 

Historic development along rivers profoundly influences how exposed Vermonters are to climate risk today: there are at least 10,000 structures within FEMA-designated Special Flood Hazard Areas (SFHA), which have a 1 in 100 chance of flooding each year. A third of all manufactured home communities are in SFHAs (see Infrastructure 7.4 and Community Development 11.3). Restoration and protection of river corridors, including wetland and floodplain habitat, is a nature-based, cost-effective solution to prepare for more frequent extreme weather events and rebuild community resilience. Research in the Otter Creek basin suggests that wetlands can reduce flood inundation costs by as much as 92% and reduce peak flow, especially during large flood events. The recently passed Vermont Flood Safety Act improves how river corridors are managed to reduce future flood risk; however, more funding is needed to help relocate willing communities out of harm’s way (see Water Resources 4.4). As of December 2025, only around 3% (8 of 264) of buyout applications were paid out by FEMA for the 2023 and 2024 flooding events. In the absence of buyouts, homeowners sell their homes in regular real estate transactions, simply transferring risk to other individuals (see Community Development 11.5). Vermont has already spent almost $600 million on clean water projects since 2016, and more funding will be needed to continue tackling climate-change impacts to water quality (see Water Resources 4.5). 

Vermont is not a climate refuge. Its rural, mountainous geography, aging infrastructure, and aging population make it more vulnerable to climate impacts that are interconnected and compounding. Flood risks, heat stress, air quality degradation (e.g., wildfire smoke, allergens), water contamination, and disruptions to infrastructure often overlap within the state—sometimes within weeks or months of each other. During a single month of July 2023, Vermonters experienced heat waves, catastrophic flooding, and wildfire smoke causing compounding impacts. Power loss from a storm can incapacitate cooling systems needed to mitigate extreme heat (see Energy 8.4). Residents with flooded homes or businesses need air flow to control mold growth but may not be able to open their windows due to wildfire smoke or extreme heat (see Human Health 10.5). 

To adapt to these impacts, Vermont needs coordinated planning and investment in natural, physical, financial, and social infrastructure. Fortunately, Vermont's strong local networks, stewardship culture, and capacity for innovation provide the foundation for responding to climate change. Throughout each chapter of the VCA, authors identify potential adaptation actions that could address climate change impacts and challenges specific to that sector. Many of these actions align with the Vermont Climate Action Plan 2025, created by the Vermont Climate Council, which provides prioritized pathways, strategies, and actions to reduce emissions and increase climate resilience. 

 Actions highlighted in the VCA include:

• Building climate-resilient roads, bridges, power systems, housing, and schools
• Enhancing flood-risk mapping and water-resource planning
• Applying nature-based approaches to flooding and drought mitigation
• Engaging in climate-adaptive forest management
• Conserving land and protecting habitat
• Promoting agricultural resilience investments and technical assistance
• Expanding healthcare and social support capacity
• Participating in energy planning that simultaneously addresses climate risk, greenhouse gas emissions, affordability, and equity
• Incorporating environmental justice into planning and decision-making