The outlook for his rivals is grim — there is almost no way they can get to the magic number.

Barring major upsets in Florida and Ohio next week, Ted Cruz will need to win approximately 70 percent of the remaining delegates to clinch the nomination outright. That essentially makes Cruz’s path to 1,237 as unlikely as Marco Rubio’s route.

Trump needs to win more than 54 percent of the remaining delegates to clinch the nomination. To do so, he would have to notch big wins on Tuesday, which has the biggest delegate haul of any remaining primary day, and then follow up with strong performances in Arizona later this month; Wisconsin, New York and several mid-Atlantic states in April; Indiana and West Virginia in May; and the major delegate prizes of California and New Jersey in June.

“A number of us who have done modeling district by district using demographics, polling, previous cycles’ results … the way we see it is Trump finishing in the 1,350- to 1,370-delegate range if he wins Ohio and Florida, and right around 1,200 without them,” said one neutral Republican strategist watching the race. “If he wins one, there’s a better chance than not he gets to 1,237,” but it would be very close.

Whether Ohio Gov. John Kasich and Florida Sen. Rubio drop out or stay in after their home-state primaries — and where their supporters go — is a major X-factor.

“It’s a little counterintuitive, but if Trump does well on Tuesday, it makes it a little more difficult for him in some of the later states,” said Adrian Gray, a former chief strategist for the Republican National Committee, because the anti-Trump vote could then consolidate behind a single remaining opponent in Cruz.

Another complicating factor: a competitive Republican presidential contest has never stretched this late into the year. Even knowledgeable GOP strategists aren’t entirely sure what to expect from suddenly important states like New York, Pennsylvania and others.

“Do blue-state Republicans always vote for the ‘establishment’ candidate because the establishment candidate is winning and will be the nominee, or do they vote establishment because they are establishment?” said another Republican strategist. “I don’t think we have the foggiest idea what those folks are going to do … because they have not been in real contests.”

Here’s how and where Trump could pick his way to 1,237 delegates over the next three months — and the different points where opponents could block his path and set up a contested convention.

March — 514 remaining delegates

Once Republicans dispense with the District of Columbia’s party convention this weekend, they’ll turn their attention to five delegate-rich primaries on March 15: Florida, Illinois, Missouri, North Carolina and Ohio.

Florida and Ohio — two winner-take-all races with favorite-son candidates — are getting most of the attention. And Trump needs to win at least one of the states to stay on track to capture the outright nomination.

In Florida, Trump holds a substantial lead over Rubio in thepublic polling, despite the home-state senator’s focus on the race there and the fact the primary is closed to non-Republicans. It’s a closer contest in Ohio, where Kasich is nipping at Trump’s heels in mostpublic polls and an anti-Trump PAC just started placing late TV advertising.

But Trump is also poised to score big hauls from Illinois and Missouri, which have open primaries and rules that could allow him to net most or all of the delegates if he wins by a large margin.A Chicago Tribune poll this week staked Trump to a 10-point lead in Illinois. There hasn’t been a public poll in Missouri this year, so the race there is more of a mystery. ButJeff Roe, Cruz’s campaign manager, is a Missouri native with a long history in state politics.

The campaigns are also fighting over North Carolina, but delegates there are awarded proportionally, mitigating the impact even a decisive win could have.

The fast and furious delegate pace slows considerably after March 15, but there are still some important contests on the calendar. On March 22, Arizona will award all 58 delegates to the statewide winner. An automated phone poll conducted earlier this week gave Trump a significant lead over Cruz in that state.

Arizona’s profile is well-suited for Trump, despite its western location: Trump’s hard-line stances on immigration — reinforced by an endorsement from Joe Arpaio, the sheriff of the state’s largest county — combined with Trump’s strong performance in neighboring Nevada make Trump the favorite there.

The other state voting on March 22 — Utah and its 40 delegates, awarded proportionally from a caucus — appears better suited for Cruz and Rubio than Trump.

April — 400 delegates

The third month of voting kicks off with the Wisconsin primary on April 5. It’s a virtual winner-take-all state: The statewide winner captures all the at-large delegates, while the winner of each congressional district gobbles up all the delegates there, too.

A Marquette Law School poll last month reported Trump with a 10-point lead over Rubio and Cruz, and a victory by that margin would likely give Trump most of Wisconsin’s 42 delegates.

The next contest comes in Trump’s home state: New York, which awards its 95 delegates proportionally in a closed primary. If Trump can run up the score — particularly in a pared-down field — he can run away with most of the delegates. Trump will win all of the delegates in each congressional district in which he can top 50 percent of the vote.

The month concludes on April 26 with a quintet of Northeastern and Mid-Atlantic states that appear tailored for Trump: Connecticut, Delaware, Maryland, Pennsylvania and Rhode Island.

There’s one wrinkle: Pennsylvania’s delegate rules could be a problem for Trump. The winner gets all of the state’s 14 at-large delegates. But congressional district-level delegates are elected directly on the primary ballot, and they won’t be bound to their preferred candidate at the convention — making them susceptible to an anti-Trump effort in Cleveland.

Along the same lines, three other states will also confirm their delegate lineups in April: Colorado, North Dakota and Wyoming. These three states won’t hold presidential preference polls this year, meaning the delegate-selection process is mostly closed to rank-and-file Republicans and could be more easily engineered by party leaders to deny Trump delegates.

May — 199 delegates

There isn’t much available polling for the handful of states that vote in May, so the outlook is murky. On top of that, it will be a slow month with five primaries spread over four weeks and delegate rules that will make it difficult for Trump to pad his margins. Nebraska is winner-take-all, but neighboring states have been kinder to Cruz. Oregon and Washington will dole out their delegates proportionally, which makes the range of potential outcomes relatively narrow.

That leaves Indiana and West Virginia, with 91 “winner-take-most” delegates, as key opportunities for Trump to stay on track for 1,237 — and for his opponents to knock him off. Neither state has been surveyed regularly, but Trump has led what polls there have been in both. They could boost him to a break-even month before decisive June primaries.

June — 303 delegates

There’s only one primary day this month, but it’s a big one — and Trump’s performance on June 7 could decide whether he wins the nomination. There are 303 delegates at stake in five states that evening, but the two most critical states for Trump will be New Jersey and California.

New Jersey’s 51 delegates will all go to the winner of the state, and Trump commanded early polls there last year even before Gov. Chris Christie dropped out of the race and endorsed him. Plus, the East has been Trump’s stronghold in this primary.

If New Jersey appears to be the most fertile territory for Trump, California has the most opportunity and danger. Trump and Cruz ran neck and neck in the last major poll of California, in January.

A close race could split the state’s 172 delegates because most of them will be awarded three at a time to the winner of each the state’s 53 congressional districts. California’s various regions can be like different states unto themselves, but Trump did not show latent strength there last year the way he did in many other states.

If more than two candidates are still in the race by this point, it could completely scramble the outlook in this final, most delegate-rich state.

The other three states up in June are Montana (27 delegates), New Mexico (24) and South Dakota (29), and all three look like roadblocks that could trip up Trump just shy of the nomination. Cruz’s better-organized campaign has already won a number of large, sparsely populated, west-of-the-Mississippi states like these, and all of Montana and South Dakota’s delegates will go to the winner.