Ukraine–Russia War: Probability of Ending Before October 1, 2026

Updated September 25, 2026

Event Definition

The event resolves positively if, before October 1, 2026, one of the following occurs:

Russia and Ukraine sign a peace treaty, armistice, or other qualifying written agreement that ends the broader war;
Russia annexes all or most of Ukraine; or
Ukraine wins the war in a manner that changes the authorities governing the Kremlin.

A temporary humanitarian pause, prisoner exchange, energy-only truce, maritime arrangement, diplomatic declaration, or agreement merely to resume negotiations would not normally qualify unless the written text clearly ends broad active hostilities.

As of September 25, 2026, there are only six calendar days—September 25 through September 30, inclusive—before the October 1 resolution date. This is materially shorter than the 10-day window available when the previous assessment was prepared.

1. Executive Forecast

Estimated probability of a qualifying event before October 1, 2026: approximately 0.1–0.3%

Central estimate: approximately 0.15%.

The forecast remains extremely low. The Trump–Zelenskyy meeting in New York took place on September 22 and generated additional diplomatic activity, but it did not produce a Russia–Ukraine ceasefire, treaty, or announced signing process. Instead, the main concrete proposals remain:

a bilateral halt to attacks on energy infrastructure;
reopening the Black Sea grain corridor; and
eventual trilateral U.S.–Russia–Ukraine talks, potentially beginning with technical-level discussions. (president.gov.ua)

These developments provide a narrow positive pathway. Ukraine says it is ready to accept an energy ceasefire, and U.S. officials are attempting to convey proposals to Moscow. However, the latest reporting indicates that an energy agreement remains elusive, the Kremlin says conditions are not ready for renewed peace talks, and there is currently no prospect for high-level Russia–Ukraine meetings. (axios.com)

The military environment has also deteriorated. On September 24, Russia launched a large combined attack involving ballistic missiles and approximately 282 drones, killing at least two people in Kyiv and damaging civilian and medical infrastructure. The attack occurred while Zelenskyy was in New York pursuing diplomacy. (investing.com)

Updated probability table

Outcome before October 1, 2026	Estimated probability
Qualifying peace treaty, armistice, or war-ending written agreement	0.1–0.3%
Russian annexation of all or most of Ukraine	Far below 0.1%
Ukrainian victory involving a change in Kremlin authorities	Far below 0.1%
War continues without a qualifying settlement	Approximately 99.7–99.9%

The positive probability is concentrated almost entirely in a sudden, U.S.-brokered written armistice. The probability of Russian annexation of most or all of Ukraine, or of a Ukrainian victory that changes the Kremlin authorities, remains effectively negligible during the remaining six days.

2. Developments Since the September 21 Assessment

2.1 Trump and Zelenskyy did meet in New York

The anticipated Trump–Zelenskyy meeting occurred on September 22 on the sidelines of the UN General Assembly. Zelenskyy’s office said that both leaders wanted the war to end before winter and discussed “potential de-escalatory steps” that could open a path to diplomacy. The discussion also covered air defense and continued U.S.–Ukrainian work on Patriot interceptor production. (president.gov.ua)

The meeting is positive evidence that Washington and Kyiv remain engaged at the highest level. It also provided a venue for narrowing Ukraine’s position on partial ceasefires and for coordinating pressure on Moscow.

Nevertheless, the meeting did not itself constitute a Russia–Ukraine agreement. There was no publicly announced nationwide ceasefire, no signed armistice, and no confirmed leader-level meeting involving Putin. Trump said he expected that “something” would happen, but the public outcome was diplomatic intent rather than an operational settlement. (apnews.com)

2.2 The U.S. is prioritizing a limited energy ceasefire

According to Zelenskyy’s account, the Trump administration is pressing for three immediate steps:

a ceasefire covering energy infrastructure;
reopening the Black Sea grain corridor; and
a trilateral U.S.–Russia–Ukraine meeting, potentially in Abu Dhabi. (axios.com)

Zelenskyy said Ukraine is ready to accept a mutual halt to attacks on energy infrastructure. He also indicated that Kyiv would accept virtually any venue or format for renewed discussions, including technical-level talks before a leader-level meeting. (axios.com)

This is the most concrete diplomatic development since the previous assessment. However, the energy proposal does not by itself satisfy the event definition. It would leave ground combat, attacks on military targets, territorial claims, and most missile and drone operations unresolved.

Furthermore, the proposal remains incomplete. The available reporting does not establish a jointly signed text, precise coverage of facilities, a start time, monitoring procedures, or consequences for violations. Axios reported that after several days of diplomacy, the energy ceasefire still appeared elusive and it was unclear whether Putin wanted the arrangement. (axios.com)

2.3 Russia has not accepted renewed high-level talks

The most important negative diplomatic development is the Kremlin’s reported position that conditions are not ready for restarting peace talks and that there is no current prospect for high-level meetings between Russia and Ukraine. (axios.com)

This substantially reduces the probability of a qualifying agreement before October 1. A nationwide armistice would require, at minimum, rapid Russian acceptance of a text, coordination with Ukraine and the United States, signature or formal adoption, and military implementation. The Kremlin’s current posture suggests that even the diplomatic channel remains stalled at the point where substantive negotiations would need to begin.

There is still a possible indirect pathway: Putin envoy Kirill Dmitriev was expected to meet Trump’s envoys Steve Witkoff and Jared Kushner in New York to discuss U.S. proposals. But such a meeting would be exploratory and would not itself amount to a Russia–Ukraine settlement. (axios.com)

2.4 Heavy Russian attacks continued during the diplomatic push

On September 24, Russia attacked Kyiv with ballistic missiles, hypersonic weapons, and approximately 282 drones. At least two people were killed and eight injured; a maternity hospital and other civilian infrastructure were damaged. The overnight attack followed additional Russian strikes earlier that day that reportedly killed two people and injured more than 40. (investing.com)

The sequence is strongly negative for the forecast. It shows that Russia is continuing major attacks even while Ukraine’s leadership is in New York discussing de-escalation with the United States.

The attacks do not logically rule out a subsequent agreement. States sometimes negotiate while escalating military pressure. But the operational evidence does not show a transition toward a nationwide ceasefire. Instead, Russia continues to use military coercion while the parties remain divided over the terms and even the format of renewed negotiations.

2.5 Ukraine remains willing to consider limited de-escalation but continues military pressure

Zelenskyy has repeatedly said that Ukraine is ready for an energy ceasefire if Russia reciprocates. On September 24, he again described Ukraine as prepared to halt energy strikes, while arguing that Ukrainian attacks on Russian oil infrastructure are responses to Russian attacks and a means of increasing pressure on Moscow. (president.gov.ua)

At the same time, Ukrainian forces reportedly continued long-range attacks against Russian oil facilities. During the September 22 Trump meeting, Zelenskyy said Ukrainian forces had damaged two additional Russian oil refineries. (apnews.com)

This produces a mixed signal:

Ukraine appears willing to pursue a limited, reciprocal energy arrangement;
Kyiv remains unwilling to rely on an unenforced Russian promise;
Ukraine continues using attacks on Russian infrastructure as leverage; and
there is no indication that Kyiv has accepted a comprehensive settlement involving Russian territorial claims.

The result is greater plausibility for a limited infrastructure truce than for a war-ending agreement.

2.6 The deadline has become even more constraining

The previous assessment was made with 10 days remaining. As of September 25, only six days remain.

The parties would need to:

resolve the scope of a possible ceasefire;
obtain Russian agreement;
agree on legal language and implementation;
establish military orders and verification mechanisms;
sign or formally adopt the agreement; and
begin implementation before October 1.

Even a rapid political announcement could occur within six days. A reliable, written agreement ending broad active hostilities is much less likely, particularly while Moscow is publicly indicating that conditions for renewed talks do not yet exist.

3. Current Diplomatic and Military Situation

United States

The Trump administration remains the principal external actor trying to reopen diplomacy. Its current approach appears focused first on limited, practical measures rather than an immediate final peace treaty:

energy infrastructure;
Black Sea shipping and grain exports;
technical-level talks; and
eventual trilateral negotiations. (axios.com)

The administration retains potential leverage through sanctions, military assistance, and the possibility of sanctions relief. However, no public evidence shows that Washington has secured Russian agreement to a nationwide ceasefire or that it can compel Moscow to accept one within the remaining six days.

Russia

Russia is combining diplomatic contacts with continued military attacks. The Kremlin has not accepted an immediate nationwide ceasefire, and current reporting says Moscow considers conditions unsuitable for resuming peace talks at a high level. (axios.com)

Russia’s September 24 attack on Kyiv further demonstrates that military pressure remains central to its strategy. Moscow may still be willing to discuss an energy or maritime arrangement, especially if it believes such an agreement would restrict Ukrainian attacks on Russian infrastructure. But there is no public evidence that Russia is prepared to end the broader war or freeze the front on terms acceptable to Ukraine.

Ukraine

Ukraine is signaling openness to reciprocal energy and maritime measures, and Zelenskyy is actively supporting renewed U.S.-brokered diplomacy. Ukraine’s official position is that ending the war remains its most important objective, but Kyiv continues to insist on reciprocal implementation and adequate security. (president.gov.ua)

Ukraine is unlikely to accept:

unilateral restrictions on its military operations;
recognition of Russian annexations as a precondition for peace;
a ceasefire that leaves Russia free to continue attacks; or
an agreement without credible monitoring and enforcement.

This leaves some space for an interim nationwide armistice that postpones territorial questions, but no evidence indicates that Moscow has accepted such a framework.

Battlefield activity

The war remains active across multiple domains:

Russia continues ballistic-missile and drone attacks against Ukrainian cities;
Ukraine continues long-range strikes on Russian oil and military infrastructure;
no verified nationwide ceasefire is in effect;
the proposed energy ceasefire has not been formalized; and
no mutually agreed monitoring or enforcement mechanism has been announced. (axios.com)

The current battlefield pattern is therefore inconsistent with a war that is already ending.

4. Evidence Supporting a Positive Resolution

4.1 The highest-level U.S.–Ukraine diplomatic channel remains active

Trump and Zelenskyy held their planned meeting, and both sides publicly described de-escalation and diplomacy as objectives. This keeps open the possibility of a last-minute U.S.-brokered initiative. (president.gov.ua)

4.2 Ukraine has expressly accepted discussion of an energy ceasefire

Ukraine’s stated willingness to join an energy ceasefire is meaningful. It removes one potential obstacle to a limited agreement and gives Washington a concrete proposal to present to Moscow. (axios.com)

4.3 U.S. officials are attempting to establish a trilateral process

The proposed sequence—technical talks, a possible meeting in Abu Dhabi, and eventually a leader-level trilateral meeting—could create a mechanism for broader negotiations. The fact that Russian, Ukrainian, and U.S. representatives remain in contact is more positive than a complete diplomatic rupture. (axios.com)

4.4 A temporary armistice could postpone the hardest territorial issues

A qualifying written agreement need not necessarily resolve sovereignty permanently. In principle, Russia and Ukraine could agree to halt broad hostilities, freeze military positions, establish monitoring, and postpone territorial-status questions.

This remains the most plausible positive pathway, but it would require a substantial change in Russia’s current position within only six days.

5. Evidence Against a Positive Resolution

5.1 Russia has not accepted the central diplomatic process

The Kremlin’s reported statement that conditions are not ready for renewed talks and that high-level meetings are not currently feasible is the strongest direct evidence against a near-term settlement. (axios.com)

5.2 The energy ceasefire is limited and not operational

The proposal would cover only a subset of infrastructure and would not end ground combat or most military operations. It also lacks a publicly confirmed joint text, monitoring system, enforcement procedure, and agreed timetable. (axios.com)

Even if signed before October 1, an energy-only truce would normally not qualify under the event definition unless it clearly expanded into a broader cessation of hostilities.

5.3 Military escalation has continued during diplomacy

The September 24 Russian attack on Kyiv involved hundreds of drones and ballistic missiles and caused civilian deaths and infrastructure damage. This is incompatible with an observable nationwide stand-down and indicates that both sides continue to view military pressure as useful. (investing.com)

5.4 Ukraine and Russia remain engaged in reciprocal infrastructure attacks

Ukraine continues striking Russian oil facilities, while Russia continues attacking Ukrainian energy and civilian infrastructure. This makes mutual trust and rapid implementation of a broad ceasefire particularly difficult. (apnews.com)

5.5 Fundamental territorial and security questions remain unresolved

The available information indicates that the current proposals concern confidence-building and de-escalation rather than final resolution of:

occupied territory;
security guarantees;
sanctions;
the line of contact;
military withdrawals;
enforcement; and
the legal status of Russian territorial claims.

A limited truce could theoretically postpone these matters, but no public evidence shows Russian acceptance of that approach.

5.6 The remaining time is exceptionally short

Six days is enough for an announcement, but not enough to assume that an announcement would become a functioning settlement. The process would need to move from indirect U.S.-mediated contacts to a signed and operational agreement almost immediately.

5.7 Military or political collapse scenarios are implausible

There is no credible evidence that Russia could annex most or all of Ukraine by September 30, nor that Ukraine could defeat Russia or cause a change in Kremlin authorities within six days. These branches contribute effectively nothing to the overall probability.

6. Scenario Analysis

Scenario A: Written nationwide armistice before October 1

Estimated probability: 0.1–0.3%

The United States persuades Russia and Ukraine to sign a written nationwide ceasefire, perhaps freezing the front while deferring territorial questions.

This remains the only realistic qualifying pathway. It is nevertheless highly unlikely because:

Russia has not accepted renewed high-level talks;
the energy ceasefire remains unfinalized;
attacks are continuing at high intensity;
no signing conference has been announced;
the parties remain divided over implementation and enforcement; and
only six days remain.

Scenario B: Energy, maritime, or infrastructure truce without ending the war

Estimated probability: 15–25%

The parties could formalize an agreement covering energy infrastructure, Black Sea shipping, or grain exports.

This scenario is materially more plausible than a nationwide armistice. Ukraine has expressed readiness, and U.S. officials are actively pressing the issue. However, the Kremlin’s resistance and the absence of a settled text make even this outcome uncertain. More importantly, it would probably not satisfy the event unless the agreement clearly ended broader hostilities.

Scenario C: Diplomatic announcement or technical talks without an operational ceasefire

Estimated probability: 35–45%

The United States, Russia, and Ukraine may announce progress, technical discussions, or plans for a later trilateral meeting. The parties may describe themselves as close to an energy or maritime arrangement while continuing to fight.

This is now the most plausible diplomatic outcome before October 1.

Scenario D: Continued fighting with limited diplomatic contact

Estimated probability: 55–65%

Russia and Ukraine continue exchanging strikes, while Washington pursues energy, maritime, and grain-related initiatives beyond the resolution date.

This remains the base case, supported by the September 24 missile and drone attack, the Kremlin’s reported rejection of immediate high-level talks, the absence of a verified ceasefire, and the extremely short remaining window. (axios.com)

Scenario E: Decisive military or political collapse

Estimated probability: far below 0.1%

This includes Russian annexation of most or all of Ukraine, collapse of the Ukrainian government, or a Ukrainian victory resulting in a change in Kremlin authorities.

There is no credible evidence that any of these developments could occur before October 1.

7. Indicators That Would Materially Increase the Forecast

The probability should rise sharply if, before September 30, any of the following occur:

Russia and Ukraine publish a signed nationwide ceasefire or armistice.
Putin publicly accepts a ceasefire along the current line of contact.
A Russian–Ukrainian or trilateral signing meeting is formally scheduled.
Russia accepts postponement of territorial-status questions.
A detailed joint energy ceasefire text is published.
The energy or maritime agreement expands to cover ground, missile, and drone operations.
A monitoring and enforcement mechanism is announced.
Russian and Ukrainian attacks decline sharply for multiple consecutive days.
Moscow and Kyiv agree on a start time and penalties for violations.
The White House announces a specific armistice text rather than general diplomatic progress.
The Kremlin reverses its position that conditions are not ready for high-level talks.
Evidence emerges of a genuine leadership crisis or political rupture in Moscow.

The forecast should fall toward or below 0.1% if:

Moscow rejects the energy proposal;
the expected envoy discussions produce no follow-up;
Russia launches further large-scale attacks;
Ukraine resumes or intensifies attacks on Russian energy infrastructure;
the United States and Ukraine fail to produce a concrete written initiative; or
negotiations are explicitly postponed until October or later.

8. Final Assessment

The September 22 Trump–Zelenskyy meeting and Ukraine’s stated willingness to accept an energy ceasefire provide genuine but limited positive evidence. The United States is attempting to move the parties toward an energy arrangement, reopen the Black Sea grain corridor, and establish a trilateral diplomatic process. (president.gov.ua)

However, these developments have not yet produced the key evidence required for a positive forecast. Russia has reportedly said that conditions are not ready for renewed high-level talks. The energy ceasefire remains incomplete and appears difficult to implement. Russia has continued large-scale missile and drone attacks, including a deadly September 24 strike on Kyiv while Zelenskyy was in New York seeking diplomatic progress. (axios.com)

The event is therefore still extremely unlikely to resolve positively before October 1. The most probable near-term development is a diplomatic announcement, technical discussion, or limited energy and maritime arrangement that leaves the broader war active.

Final forecast

Estimated probability that the Ukraine–Russia war ends through a qualifying peace treaty, armistice, settlement, Russian annexation of Ukraine, or Ukrainian victory involving a change in Kremlin authorities before October 1, 2026: approximately 0.1–0.3%, with a central estimate near 0.15%.

The most likely outcome remains that the war continues beyond October 1, 2026, even if Washington, Moscow, and Kyiv announce renewed technical talks or a limited infrastructure arrangement. A last-minute nationwide armistice remains theoretically possible but would require a rapid reversal of Russia’s current negotiating posture, a jointly accepted text, and operational implementation within only six days.

Source Document for Event 2 (25-09-2026)