Fifty-three congressional districts, 415 pledged delegates, potentially 10 million voters — California is the big kahuna of Super Tuesday. According to the FiveThirtyEight primary forecast, Sen. Bernie Sanders is golden in the Golden State; he has a 9 in 10 (90 percent) chance of winning the most votes. But because of California’s massive size, the results here are significant beyond who wins and loses. Finishing in second place with, say, 25 percent of the vote can represent the support of millions of people — and potentially win a candidate more delegates than were available in the four early states combined.

In the average FiveThirtyEight model run, Sanders gets 35 percent of the vote in California, former Vice President Joe Biden gets 25 percent, and Sen. Elizabeth Warren and former New York City Mayor Michael Bloomberg both get 16 percent. Any candidate who gets 15 percent or more of the statewide vote is guaranteed some number of California’s 144 statewide delegates, so the exact results will be important to watch. Given the wide range of uncertainty in our forecast, there is real suspense over whether Warren and Bloomberg will manage to cross the 15-percent threshold, and if they do, by how much. And if Sanders and Biden do notably better or worse than expected, it could add or subtract dozens of delegates to their totals.

The remaining 271 pledged delegates out of California are awarded based on the results in each of the state’s congressional districts, worth between four and seven delegates each. This is no small matter; California is demographically diverse, which means different corners of the state can be worlds apart. According to our forecast, this translates into different congressional districts supporting different Democratic candidates.

There’s a stark geographic divide in California Top candidates’ average forecasted vote share in California congressional districts, according to FiveThirtyEight’s model as of 5:40 p.m. on March 2 District Sanders Biden Warren Bloomberg CA-01 34% 25% 16% 17% CA-02 35 23 17 16 CA-03 34 26 16 16 CA-04 35 24 17 16 CA-05 35 25 16 16 CA-06 33 28 15 17 CA-07 35 25 17 16 CA-08 32 29 14 17 CA-09 33 28 15 17 CA-10 34 27 15 17 CA-11 35 24 17 15 CA-12 38 20 20 14 CA-13 34 25 17 15 CA-14 38 21 19 14 CA-15 37 22 18 14 CA-16 32 29 14 17 CA-17 39 20 20 12 CA-18 38 19 20 13 CA-19 37 23 18 14 CA-20 35 25 16 16 CA-21 31 31 13 17 CA-22 33 28 15 17 CA-23 33 28 15 17 CA-24 35 24 17 16 CA-25 34 26 16 16 CA-26 36 24 17 15 CA-27 36 23 18 15 CA-28 35 23 18 16 CA-29 34 27 15 17 CA-30 36 23 18 15 CA-31 33 28 15 16 CA-32 34 26 16 16 CA-33 37 20 20 14 CA-34 34 27 16 17 CA-35 33 29 15 16 CA-36 32 29 14 17 CA-37 31 29 15 17 CA-38 34 27 16 16 CA-39 37 23 18 14 CA-40 32 29 14 17 CA-41 32 29 14 17 CA-42 35 26 16 16 CA-43 31 31 14 17 CA-44 31 31 14 17 CA-45 37 21 19 14 CA-46 35 26 16 16 CA-47 35 25 16 16 CA-48 37 21 19 15 CA-49 36 22 18 15 CA-50 35 24 17 16 CA-51 32 29 14 17 CA-52 37 20 19 14 CA-53 35 25 17 16 State 35 25 17 15

Sanders’s support figures to be pretty steady across the state; we’re forecasting him to get between 31 and 39 percent of the vote in every district. That’s enough for him to finish first almost everywhere. Biden’s support fluctuates a lot more based on a district’s demographics; his highs (e.g., 31 percent in the 44th District) are high enough for him to beat Sanders in some areas, but his lows (e.g., 19 percent in the 18th District) are low enough that he has a chance of falling beneath the qualifying threshold in others. Warren and Bloomberg, like Sanders, figure to perform pretty consistently from district to district, but because those performances are consistently close to 15 percent, every percentage point will matter. Right now, we’re forecasting Warren and Bloomberg to be eligible for delegates in 39 districts each, but those numbers could easily be zero or 53 with small shifts in their statewide support.

In general, Biden and Bloomberg overperform their statewide performances in the districts where Sanders and Warren underperform, while Sanders and Warren overperform their statewide performances in the districts where Biden and Bloomberg underperform. We won’t bore you by going through all 53 districts, but here’s an overview of what distinguishes each kind of district.

Let’s start with the districts where Biden and Bloomberg overperform. While Sanders certainly isn’t forecasted to do poorly in any of these districts, they are below average for him — enough that he and Biden should run about even in them. The districts listed below are also generally Warren’s worst in the entire state; we’ll be watching them to see whether Warren falls below 15 percent and gets shut out of delegates there.

Some of Biden’s (and, to a lesser extent, Bloomberg’s) best districts can be found south of downtown Los Angeles on either side of the 110. These are among the most densely populated districts in the state and are heavily nonwhite. For example, we’re forecasting Biden to get 29 percent in the 40th District (which includes South Central Los Angeles, East Los Angeles and Downey), which is both the least white and most Latino district in the state. The 44th District (Compton, San Pedro), which is 93 percent nonwhite, is expected to be Biden’s best district in the whole state. And the nearby 37th District (Culver City, Vermont Square) and 43rd District (Inglewood, Torrance) have the two largest black populations in California, and Biden has consistently polled well among black voters.

Biden is also strong in majority-minority rural districts, like those in the Central Valley. And these are also the districts where Bloomberg has the best chance to pick up delegates. For example, the 21st District (covering much of the San Joaquin Valley between Fresno and Bakersfield), an agricultural district that is 74 percent Latino, is forecasted to give Biden 31 percent and Bloomberg 17 percent. You can also look to places like the 16th District (Fresno, Merced) and 36th District (Palm Springs and the desert communities in eastern Riverside County) to get an idea of Bloomberg’s California ceiling.

In general, Biden and Bloomberg tend to be strong in districts with low median incomes and relatively small shares of college-educated voters. And perhaps unsurprisingly, these districts have also historically voted for establishment Democrats. The 36th, 43rd and 21st districts were former Secretary of State Hillary Clinton’s three best districts in California in the 2016 primary, going for her over Sanders by more than 20 points.

On the flip side, Biden and Bloomberg do especially badly — and Warren excels — in districts encompassing California’s most upscale suburbs. In fact, Biden’s very worst district, and Warren’s very best, is the 18th District (Palo Alto, Mountain View, Campbell, Los Gatos) in Silicon Valley. Sixty-two percent of its adult population holds at least a bachelor’s degree, and it has the highest median household income in the state: $122,124 a year. It’s a similar story in the 33rd District (Malibu, Santa Monica) in coastal Los Angeles; its high white (65 percent, fourth among California districts) and college-educated (64 percent, first) population is a bad combination for Biden and Bloomberg. And in the predominantly white and college-educated 52nd District (western San Diego, La Jolla), Biden underperforms his statewide average by 4 points.

Warren also does well in more racially diverse upscale districts, especially in the Bay Area. We’re forecasting her to get 19 percent or more in the 17th District (Santa Clara, Milpitas, Fremont), the 12th District (San Francisco) and the 14th District (South San Francisco, San Mateo) — cosmopolitan, diverse districts all. In Southern California, Warren also overperforms in districts that fit a similar profile, such as the 39th District (Fullerton, Yorba Linda) and 45th District (Irvine, Mission Viejo) in Orange County. Both are well-to-do and have significant white, Asian and Latino populations.

Finally, there are several districts where no candidate departs significantly from his or her statewide forecast. These bellwether districts include places like the 20th District (Santa Cruz, Salinas), 5th District (Santa Rosa, the city of Napa) and 53rd District (eastern San Diego, Chula Vista). But we are expecting the 7th District (Sacramento’s eastern suburbs) to most closely approximate the Democratic electorate statewide. The district is representative of California in terms of income, education and density, although it is a fair bit whiter than the state as a whole.

In a perfect world, you’d be able to follow the results in each of these districts on Tuesday night and use them to predict which candidates are on track to over- or underperform statewide. But in California, you should treat the election-night results as incomplete. That’s because a majority of Californians vote by mail, and ballots need only be postmarked by Election Day; election offices can receive them as late as Friday. And in a state where some counties have more eligible voters than entire states, full results from California will take days, maybe even weeks, to report.

And the initial results are not guaranteed to be representative, either. For instance, young voters tend to wait until the last minute to mail their ballots, so they may be underrepresented in the early results; because Sanders is so popular with young voters, that might mean he will be disproportionately weak in the initial count. Biden, too, might be stronger among last-minute voters, if he receives a polling bump from his decisive win in South Carolina.

The bottom line is that California is a big, complicated state. We should wait until every vote is counted before forming our final opinions about who won and who lost.