2026 Midterm Election Forecast: Senate, House and Governors

How the forecast works

The model estimates each race's margin (the Democratic or independent candidate minus the Republican) from three inputs, then simulates the election 40,000 times to turn margins into probabilities.

1. Polling average. General-election polls compiled by 270toWin, weighted by recency (a poll's weight halves every 14 days), sample size and population: likely-voter polls count more than registered-voter or adult samples. Undecided voters are not allocated; only the gap between the candidates is used.
2. Expert ratings. The published ratings of up to 12 forecasters, including the Cook Political Report, Inside Elections and Sabato's Crystal Ball, converted to a margin (Safe 22, Likely 12, Lean 6, Tilt 3, Toss-up 0 points) and averaged. Ratings carry information polls do not, such as candidate quality, fundraising and private polling.
3. Fundamentals. The state's or district's partisan lean (2026 Cook PVI, which accounts for redrawn House maps), plus the national environment from the generic congressional ballot (D+7.8 in late-October polling; the model centers on D+7.5), plus about three points for an incumbent seeking re-election. Governor's races get less partisan weight because voters split tickets for governor more often.

Blending. A race with plenty of recent polling is about 62% polls, 23% ratings and 15% fundamentals. Races with little polling lean on ratings and fundamentals; House districts, which are rarely polled, are a blend of ratings and fundamentals.

Simulation. Each simulated election draws one national error (standard deviation 3.3 points) that moves every race in the same direction, as real polling misses do, plus a separate race-level error from a fat-tailed distribution (about 4 points for well-polled races, up to 7 for unpolled ones). A party's win probability is the share of simulations it wins, and chamber control is counted the same way.

Updates. The forecast reruns automatically every two hours: it collects newly posted polls, recomputes each polling average and reruns the simulations, and this page, the state pages and the interactive map all update together. Expert ratings and fundamentals stay fixed as of the last review. After Election Day the forecast is frozen so it can be scored against the results.

Ratings on this page come from the projected margin: Toss-up when the projected margin is under 1.5 points, Tilt under 4.5, Lean under 9, Likely under 17, and Safe at 17 or more.

Limitations. Alaska's ranked-choice voting, Louisiana's new closed primaries, candidate scandals and events after the model run are reflected only through the polls and ratings.