Why Do Summer Storms Cause More Power Outages Than You Think in New England?

When most people in Manchester, Hudson, and across Southern New Hampshire think about power outages, their minds go straight to February ice storms or nor’easters that pile snow on the power lines. Winter storms are real and damaging. But summer? That’s supposed to be the easy season.

Here’s the truth: summer storms knock out power across New England far more often, and far more unpredictably, than most homeowners realize. And because most people aren’t prepared for a July blackout the way they are for a January one, the disruption hits harder.

At Cote Electric, we’ve been serving Manchester, Hudson, and communities throughout South and Central New Hampshire, and Southern Maine since 1987. We’ve seen firsthand what summer storms do to local homes and electrical systems. This post breaks down why summer outages are so common, why they’re getting worse, and most importantly, what you can do right now to protect your home.

The Surprising Truth About Summer Storm Outages

Most people assume power outages are a winter problem. But severe weather, including thunderstorms, high winds, and heavy rain, actually accounts for 58% of all major weather-related power outages in the United States, according to Climate Central’s analysis of federal utility data. Winter storms represent just 23%. Summer thunderstorm season is, by far, the primary driver of outages nationwide.

The Northeast is no exception. Climate Central’s research found that the Northeast experienced 346 major weather-related outages between 2000 and 2023, with severe weather (not winter storms) responsible for the majority.

In New Hampshire, that reality plays out every single summer. Just this past June 2026, a fast-moving thunderstorm left more than 20,000 customers without electricity statewide at its peak, with communities like Derry, Manchester, Bedford, Londonderry, and Merrimack all reporting significant outages. The month prior, a separate storm system knocked out power to more than 18,200 customers in the Granite State in a single morning event.

These aren’t freak occurrences. This is summer in New England.

Why Summer Storms Hit the New England Grid So Hard

Several forces converge during the summer months that make outages both more likely and harder to predict.

1. Trees Are in Full Leaf, and Full Force

This is the single biggest factor. Eversource, New Hampshire’s largest utility provider, has stated that trees cause more than 90% of power outages during storms across their service territory. In winter, bare trees snap, but their contact with power lines is more predictable. In summer, trees are carrying the full weight of their leaves, which dramatically increases wind resistance and the likelihood of large branches and entire trees coming down across lines.

New England’s density of mature hardwoods along older residential streets in Manchester, Hudson, and throughout Hillsborough County is beautiful. It’s also a structural vulnerability every storm season.

2. Thunderstorm Intensity Has Increased

New England summers have grown stormier. Warmer, more moisture-laden air moving up from the Gulf creates the atmospheric instability that produces powerful, fast-moving thunderstorms with wind gusts well above 58 mph, the threshold at which power lines and poles are at serious risk of damage. The National Weather Service flagged wind gusts up to 65 mph in some areas during the May 2026 storm system that battered New Hampshire simultaneously.

Microbursts are concentrated, violent downdrafts that can topple entire sections of electrical infrastructure in a matter of seconds. They’re especially dangerous precisely because they’re largely unpredictable.

3. Lightning Creates Invisible Damage

Thunderstorms don’t just knock down trees. Lightning creates electromagnetic pulses that can damage sensitive electrical equipment even without a direct strike. Transformers can be overloaded and fail. Surges can travel through your home’s wiring and fry appliances, electronics, and HVAC systems before you even know a storm is serious.

This is one of the most underappreciated risks of summer storms, and it’s why whole home surge protection is one of the most valuable investments a New Hampshire homeowner can make, whether or not you already have a generator.

4. Grid Stress from Summer Heat

Summer outages come from two directions at once. Beyond storm damage, heat waves push energy demand to its seasonal peak as millions of air conditioners run simultaneously. The Department of Energy has specifically flagged extreme weather events and grid stress as increasing factors in outage frequency. When the grid is already strained by high demand and a storm rolls in, the combination is particularly disruptive.

The New England ISO grid faces this precise challenge every summer: a mix of moderate heat and severe weather events that compound grid stress in ways that are fundamentally different from other regions of the country.

5. Aging Infrastructure Wasn’t Built for This

Much of New England’s electrical grid was originally installed between the 1950s and the 1970s, putting many transmission lines and distribution components at or beyond their expected service lifespan. Those above-ground utility poles, transformers, and overhead lines were engineered for the weather patterns of decades past. They were not built for the more intense, more frequent storm events that characterize the region today.

In communities throughout our service area, including Manchester, Nashua, Hudson, Salem, and into Southern Maine, that aging infrastructure is a constant variable in every summer storm season.

What Happens Inside Your Home During a Storm Outage

A summer power outage isn’t just an inconvenience. Depending on how long it lasts and what’s running in your home, the consequences can range from costly to genuinely dangerous.

Sump pump failure is a leading concern during summer storms. If your power goes out during a heavy rain event, exactly when your sump pump needs to be running, you can face serious basement flooding within hours.

Food loss accumulates quickly. A refrigerator maintains safe temperatures for roughly 4 hours once power is lost; a freezer, 48 hours if full. A multi-day outage following a major storm can mean hundreds of dollars in spoiled food.

HVAC shutdown during a heat wave can create dangerous conditions, especially for elderly residents and young children. New Hampshire summers can push temperatures into the 90s, and a home without air conditioning or fans becomes unsafe quickly.

Surge damage on restoration is another hidden risk. When power is restored after an outage, voltage fluctuations and surges travel through your home’s wiring. Without whole home surge protection in place, sensitive electronics, smart appliances, and HVAC systems are all vulnerable to damage at the exact moment power comes back on, not just while it’s out.

Electrical panel stress from repeated outage cycles can accelerate wear on breakers and connections, especially in older homes. If your panel is already aging, summer storm season is when problems that have been slowly developing tend to surface.