| Year | Minutes to midnight | Time (24-h) | Change (minutes) | Reason | Clock |
| 1947 | 7 | 23:53 | 0 | The initial setting of the Doomsday Clock. | |
| 1949 | 3 | 23:57 | −4 | The Soviet Union tests its first atomic bomb, the RDS-1, starting the nuclear arms race. | |
| 1953 | 2 | 23:58 | −1 | The United States tests its first thermonuclear device in November 1952 as part of Operation Ivy, before the Soviet Union follows suit with the Joe 4 test in August. This remained the clock's closest approach to midnight (tied in 2018) until 2020. | |
| 1960 | 7 | 23:53 | +5 | In response to a perception of increased scientific cooperation and public understanding of the dangers of nuclear weapons (as well as political actions taken to avoid "massive retaliation"), the United States and Soviet Union cooperate and avoid direct confrontation in regional conflicts such as the 1956 Suez Crisis, the 1958 Second Taiwan Strait Crisis, and the 1958 Lebanon crisis. Scientists from various countries help establish the International Geophysical Year, a series of coordinated, worldwide scientific observations between nations allied with both the United States and the Soviet Union, and the Pugwash Conferences on Science and World Affairs, which allow Soviet and American scientists to interact. | |
| 1963 | 12 | 23:48 | +5 | The United States and the Soviet Union sign the Partial Test Ban Treaty, limiting atmospheric nuclear testing. | |
| 1968 | 7 | 23:53 | −5 | The involvement of the United States in the Vietnam War intensifies, the Indo-Pakistani War of 1965 takes place, and the Six-Day War occurs in 1967. France and China, two nations which have not signed the Partial Test Ban Treaty, acquire and test nuclear weapons (the 1960 Gerboise Bleue and the 1964 596, respectively) to assert themselves as global players in the nuclear arms race. | |
| 1969 | 10 | 23:50 | +3 | Every nation in the world, with the notable exceptions of India, Israel, and Pakistan, signs the Nuclear Non-Proliferation Treaty. | |
| 1972 | 12 | 23:48 | +2 | The United States and the Soviet Union sign the first Strategic Arms Limitation Treaty (SALT I) and the Anti-Ballistic Missile (ABM) Treaty. | |
| 1974 | 9 | 23:51 | −3 | India tests a nuclear device (Smiling Buddha), and SALT II talks stall. Both the United States and the Soviet Union modernize multiple independently targetable reentry vehicles (MIRVs). | |
| 1980 | 7 | 23:53 | −2 | Unforeseeable end to deadlock in American–Soviet talks as the Soviet–Afghan War begins. As a result of the war, the U.S. Senate refuses to ratify the SALT II agreement. | |
| 1981 | 4 | 23:56 | −3 | The Soviet war in Afghanistan toughens the U.S.' nuclear posture. U.S. President Jimmy Carter withdraws the United States from the 1980 Summer Olympic Games in Moscow. The Carter administration considers ways in which the United States could win a nuclear war. Ronald Reagan becomes President of the United States, scraps further arms reduction talks with the Soviet Union, and argues that the only way to end the Cold War is to win it. Tensions between the United States and the Soviet Union contribute to the danger of nuclear annihilation as they each deploy intermediate-range missiles in Europe. The adjustment also accounts for the Iran hostage crisis, the Iran–Iraq War, China's atmospheric nuclear warhead test, the declaration of martial law in Poland, apartheid in South Africa, and human rights abuses across the world. | |
| 1984 | 3 | 23:57 | −1 | Further escalation of the tensions between the United States and the Soviet Union, with the ongoing Soviet–Afghan War intensifying the Cold War. U.S. Pershing II medium-range ballistic missile and cruise missiles are deployed in Western Europe. Ronald Reagan pushes to win the Cold War by intensifying the arms race between the superpowers. The Soviet Union and its allies (except Romania) boycott the 1984 Olympic Games in Los Angeles, as a response to the U.S.-led boycott in 1980. | |
| 1988 | 6 | 23:54 | +3 | In December 1987, the United States and the Soviet Union sign the Intermediate-Range Nuclear Forces Treaty, to eliminate intermediate-range nuclear missiles, and their relations improve. | |
| 1990 | 10 | 23:50 | +4 | The fall of the Berlin Wall and the Iron Curtain, along with the reunification of Germany, mean that the Cold War is nearing its end. | |
| 1991 | 17 | 23:43 | +7 | The United States and Soviet Union sign the first Strategic Arms Reduction Treaty (START I), the US announces the removal of many tactical nuclear weapons in September 1991, and the Soviet Union takes similar steps, as well as announcing the complete cessation of all nuclear testing in October 1991. The Bulletin editorial, published November 26, 1991, announces that "the 40-year-long East-West nuclear arms race is over." One month after the Bulletin made this clock adjustment, the Soviet Union dissolves on December 26, 1991. This is the farthest from midnight the Clock has been since its inception. | |
| 1995 | 14 | 23:46 | −3 | Global military spending continues at Cold War levels amid concerns about post-Soviet nuclear proliferation of weapons and brainpower. | |
| 1998 | 9 | 23:51 | −5 | Both India (Pokhran-II) and Pakistan (Chagai-I) test nuclear weapons in a tit-for-tat show of aggression; the United States and Russia run into difficulties in further reducing stockpiles. | |
| 2002 | 7 | 23:53 | −2 | Little progress on global nuclear disarmament. United States rejects a series of arms control treaties and announces its intentions to withdraw from the Anti-Ballistic Missile Treaty, amid concerns about the possibility of a nuclear terrorist attack due to the amount of weapon-grade nuclear materials that are unsecured and unaccounted for worldwide. | |
| 2007 | 5 | 23:55 | −2 | North Korea tests a nuclear weapon in October 2006, Iran's nuclear ambitions, a renewed American emphasis on the military utility of nuclear weapons, the failure to adequately secure nuclear materials, and the continued presence of some 26,000 nuclear weapons in the United States and Russia. After assessing the dangers posed to civilization, climate change was added to the prospect of nuclear annihilation as the greatest threats to humanity. | |
| 2010 | 6 | 23:54 | +1 | Worldwide cooperation to reduce nuclear arsenals and limit effect of climate change. The New START agreement is ratified by both the United States and Russia, and more negotiations for further reductions in the American and Russian nuclear arsenal are already planned. The 2009 United Nations Climate Change Conference in Copenhagen results in the developing and industrialized countries agreeing to take responsibility for carbon emissions and to limit global temperature rise to 2 degrees Celsius. | |
| 2012 | 5 | 23:55 | −1 | Lack of global political action to address global climate change, nuclear weapons stockpiles, the potential for regional nuclear conflict, and nuclear power safety. | |
| 2015 | 3 | 23:57 | −2 | Concerns amid continued lack of global political action to address global climate change, the modernization of nuclear weapons in the United States and Russia, and the problem of nuclear waste. | |
| 2017 | mw- .mw- 2+1⁄2 | 23:57:30 | −1⁄2(−30 s) | United States President Donald Trump's comments over nuclear weapons, the threat of a renewed arms race between the U.S. and Russia, and the expressed disbelief in the scientific consensus over climate change by the Trump administration. | |
| 2018 | 2 | 23:58 | −1⁄2(−30 s) | Failure of world leaders to deal with looming threats of nuclear war and climate change. This is the clock's third closest approach to midnight, matching that of 1953. In 2019, the Bulletin reaffirmed the "two minutes to midnight" time, citing continuing climate change and Trump administration's abandonment of U.S. efforts to lead the world toward decarbonization; U.S. withdrawal from the Paris Agreement, the Joint Comprehensive Plan of Action, and the Intermediate-Range Nuclear Forces Treaty; U.S. and Russian nuclear modernization efforts; information warfare threats and other dangers from "disruptive technologies" such as synthetic biology, artificial intelligence, and cyberwarfare. | |
| 2020 | 1+2⁄3(100 s) | 23:58:20 | −1⁄3(−20 s) | Failure of world leaders to deal with the increased threats of nuclear war, such as the end of the Intermediate-Range Nuclear Forces Treaty (INF) between the United States and Russia as well as increased tensions between the U.S. and Iran, along with the continued neglect of climate change. Announced in units of seconds, instead of minutes; this was the clock's closest approach to midnight, exceeding that of 1953 and 2018. The Bulletin concluded by stating that the current issues causing the adjustment are "the most dangerous situation that humanity has ever faced". In the annual statements for 2021 and 2022, issued in January of each year, the Bulletin left the "100 seconds to midnight" time setting unchanged. | |
| 2023 | 1+1⁄2(90 s) | 23:58:30 | −1⁄6(−10 s) | Due largely–but not exclusively–to the Russian invasion of Ukraine and the increased risk of nuclear escalation stemming from the conflict. Russia suspended its participation in the last remaining nuclear weapons treaty between it and the United States, New START. Russia also brought its war to the Chernobyl and Zaporizhzhia nuclear reactor sites, violating international protocols and risking widespread release of radioactive materials. North Korea resumed its nuclear rhetoric, launching an intermediate-range ballistic missile test over Japan in October 2022. Continuing threats posed by the climate crisis and the breakdown of global norms and institutions set up to mitigate risks associated with advancing technologies and biological threats such as COVID-19 also contributed to the time setting. This setting remained unchanged the following year. | |
| 2025 | 1+29⁄60(89 s) | 23:58:31 | −1⁄60(−1 s) | The continuing Russian invasion of Ukraine and the Middle Eastern crisis, increased nuclear proliferation, effects of climate change, biological threats, and advancing technologies. This is the closest to midnight the Clock has been since its inception. | |
