As a WMG page, all spoilers are unmarked!
The Winter was caused by The Tomorrow Corporation deliberately messing with the atmosphere to trick consumers into buying (and later burning) their crappy stuff.
Some believe the game's about consumerism, after all.The game takes place after the events of Human Resource Machine
The Robots destroyed the Earth so much that it was plunged into an eternal winter, and the Tomorrow Corporation used it as an opportunity to make boatloads of cash.Tomorrow Corporation's building in this game is (at least similar to) the building from Human Resource Machine
This game's building has a Holodeck-like room capable of simulating Tropical-like Temperatures. HRM has a cutscene that randomly takes place in a beach. Since we never go outside of the building (the rest of the "Coffee Breaks" take place in an office of the building, excluding the ending where you're replaced by a computer, and you leave the building), it's safe to say this scene was in this Holodeck-like room.Sugar Plumps truly did die when her house burned down
When she says she "left her house" it was actually her ghost, who sends you the letters during the final catalog. After burning the four items you sent to her, her ghost is allowed to pass on to the afterlife, which is where she sends you the final letter from.After the ending, the player character ultimately goes to space.
Though everything about the world seems calculated to make the population content or oblivious even in the face of impending doom, there's a subtle pushback in the Arc Words: "Nothing can last forever," "There's something even worse than fire," "You can go as far as you want, but you can't go back." Those who break away from the Little Inferno loop, like Sugar Plumps and the player character, are given the chance to make their own decisions, and those who leave the city meet The Weatherman, who will take them up, up, UP! That is, to space. We know that space travel is possible thanks to Miss Nancy and her rocket, and with the world ending it'd be a good idea to find a new one. Most people have become incapable of settling a new world, so the subtle messages and the Weatherman are part of a plan to rescue those with potential, those who can think for themselves and are willing to leave everything behind in search of something more meaningful.