Hygiene: R. The weather deities did not smile upon the mayor in his first few months: Successive snowstorms prompted heavily scrutinized decisions on school closings and made enemies of snowed-in Upper East Side residents and, at least briefly, Al Roker. (The weatherman’s gripe: Mr. de Blasio left schools open in a blistering storm.) Still, the blizzards — which have not yet been reprised in his second winter — supplied an instant opportunity for the mayor to demonstrate leadership in a crisis. He flashed a personal touch, shoveling in front of his own home in Brooklyn and performing a mock striptease in response to a question about his clothing layers. He also reconciled with Mr. Roker. M.F.

Science and Math

Health: S. Trying to save Long Island College Hospital in Brooklyn from being turned into condominiums, Mr. de Blasio overpromised, saying the battle was won. Months later, the property was sold for — yes, condominiums (with some health care thrown in). But the mayor became the voice of reason when a doctor home from West Africa, Craig Spencer, developed Ebola: He tamped down fears that the virus could spread in the subways, ate meatballs at a shop the doctor had patronized and denounced the stigmatization of hospital workers. Then, when Dr. Spencer was released, the mayor led everyone in administering a round of hugs. ANEMONA HARTOCOLLIS

Earth Science: I. With a cadre of diplomats in town to discuss climate change at the United Nations in September, Mr. de Blasio moved to make his mark: promising to overhaul the energy-efficiency standards of all municipal buildings and pressing private landlords to do the same. Though some activists have suggested that the mayor needed a bit of a push on climate issues, his major plan has been well received. M.F.

Technology: I. Mr. de Blasio stopped the long-delayed procurement of a new 911 system that was $1 billion over budget after learning that it still would not be completed until 2018. The Department of Investigation is examining what went wrong. In another plan, the city is pushing to create Wi-Fi hot spots across the city at old public pay phones, in a bid to help close the “digital divide” — though Mr. de Blasio drew criticism from the city comptroller, who warned that the plan, to be paid for with advertising, could actually perpetuate inequality by providing faster Internet speed in wealthier neighborhoods than in others. N.S.

Biology: R. For Mayor de Blasio, City Hall is a family affair. His wife, Chirlane McCray, holds an unpaid post leading the Mayor’s Fund to Advance New York, and their children, Chiara and Dante de Blasio, had unpaid summer internships in city government. But Mr. de Blasio has protected them from the harsh glare of the spotlight. In May, he scolded The Daily News and The New York Post for misunderstanding his wife’s comments in a New York magazine cover story recalling her struggles years ago as a new mother torn between work and home. The Post headline read, “I Was a Bad Mom.” The mayor demanded an apology. N.S.

Arithmetic: S. The mayor said he would not engage in “Kabuki theater” when it came to his first spending plan. But his proposed $73.7 billion budget included a tax on wealthy residents to pay for the expansion of prekindergarten classes that the governor and state legislators said wouldn’t be approved. (Mr. de Blasio later procured state funding without the tax.) The final budget grew by $1 billion and included new investments in public housing and a plan to provide free lunch to all middle school children. He also found enough money to cut new labor deals with most of the city workforce. N.S.

Calculus: R. Discipline, stagecraft, leverage — this mayor plays politics like a pro. He handpicked a City Council speaker and consolidated power by creating a nonprofit fund-raising operation exempt from many city disclosure rules. Yet he projected an image as a family man ambivalent about fame. His strained relations with the Police Department turned into a major crisis by year’s end. But the mayor still has immense support among liberals and blacks, and that, advisers say, is enough to recapture the Democratic line in 2017. M.M.G.