Svitlana Zinovieva wiped icy condensation from her living room window and pointed to a smokestack rising from a central boiler heating her apartment block. There, in the distance, she had seen a Russian missile streak in and explode a few days before.

“It was like fireworks,” she said. “But I knew it would soon be cold.”

Not long after, the bitter chill of the coldest winter in a decade in Kyiv, the Ukrainian capital, was seeping into her apartment. Ms. Zinovieva quickly adopted new routines, like countless other Ukrainians coping with Russia’s unrelenting assaults on their country’s heating and electrical systems.

With the power out and her refrigerator useless, a glassed-in balcony became her freezer as inside temperatures fell. Before bed, Ms. Zinovieva, 73, a retired cinematographer, warmed water on a stove to fill empty wine bottles. She placed them inside a tent pitched on her bed. Then she climbed inside, warm at last.

“It’s really very cozy,” she said of the indoor tent.

Ukrainians have watched breakthroughs and setbacks on the battlefield, slept in basements, mourned their dead, and lamented the loss of the United States as a reliable ally. They are now approaching the fourth anniversary of Russia’s all-out invasion bundled up in their homes in sweaters, long underwear and multiple pairs of socks.