Arizona · Governor

Who is running?

Katie Hobbs (Democratic), Andy Biggs (Republican), Risa Lombardo (Green), Teri Ann Hourihan (No Labels). The margin below is Katie Hobbs minus the other candidate in the main contest; the rest are on the ballot and not in it.

The race, in brief

Arizona elects its governor on November 3, 2026. The text calls Arizona a purple state: Biden carried it narrowly in 2020 and Trump carried it by 5.5 points in 2024. Democrats hold both U.S. Senate seats and the governorship, while Republicans hold majorities in both legislative chambers and 6 of the 9 U.S. House seats. The state profile on file records a Hispanic share of 0.3, a college share of 0.3 and a median age of 38.8. This is the first race in which candidates must name a lieutenant-governor running mate.

Democratic incumbent Katie Hobbs, governor since 2023, is seeking a second term and was unopposed in the July 21 primary; her running mate is John Giles, former mayor of Mesa, an Independent. The Republican nominee is U.S. representative Andy Biggs, with former state senator Sine Kerr as running mate. The lede gives Biggs 73.6% over David Schweikert, while the results table shows 74.0% to Schweikert's 14.4%. The Green nominee, Risa Lombardo, was disavowed by her own state party, and No Labels has nominated Teri Hourihan.

All seven raters listed call the race D, with dates from June 5, 2026 (RealClearPolitics) to September 23, 2026 (Decision Desk HQ). The page's polling average is Hobbs 47.5%, Biggs 39.1%, Hobbs +8.4%. As of June 30, 2026 Hobbs had raised $10,094,991 with $1,993,886 on hand, and Biggs $3,239,471 with $1,266,182 on hand.

A paragraph quoting a model forecast from the day this brief was written is omitted; the current forecast is at the top of this page.

The facts, each beside its sentence

Not in the source: facts.candidates marks Hobbs incumbent: false, but the text says she is the Democratic incumbent.; The text gives two Biggs primary shares (73.6% in the lede, 74.0% in the results table).; The forecast rows carry no basis field, so the brief cannot say what the model is standing on or whether it uses the listed statewide polls.; Rater calls are given only as 'D', with no Lean/Likely/Safe detail.; No general-election result for 2022 (Hobbs's first win) is given in the text.

Read from the district's section of Wikipedia's state page (CC BY-SA), archived as 20459f14dd27; written by claude-opus-5-5 (batch reader) on 2026-09-30 and checked mechanically: every quote occurs verbatim in the archived text, every number in the brief occurs in the inputs. No probability here is the reader's.

How it has voted for president

A shift of 1.8 points toward the Republicans from 2016 to 2024. county returns summed; MEDSL county file (2016), an MIT-licensed county file (2020, checked against certified state results) and MEDSL precinct returns (2024). For a district split across counties this is an estimate, and where the state published the exact 2024 figure for these lines, that exact figure is the one the model uses.

The state in numbers

ACS 5-year state tables; BLS county unemployment and BEA county income, transfers and jobs summed to the state. Every figure is a named column of a named public-domain table, archived before it was read.

Who is ahead, and by how much?

Two numbers because they answer two questions. The nowcast is where opinion stands; the election-day forecast is where it is likely to end up.

How likely is each to win?

Monte Carlo error is ±0.2 points. A change smaller than that is simulation noise rather than news, and this page will not describe it as movement.

How wide is the range?

Nowcast: 90% of simulations fall between -4.5 and +14.5 points. Election day: -4.3 to +18.5. The election-day interval is 3.9 points wider, which is the 33 days of movement still to come.

What is the uncertainty made of?

Total sd 7.28 points, made of race-specific polling error 47%, drift to election day 31%, latent opinion 11%, correlated polling error 11%. The decomposition is stored with the forecast rather than reconstructed, so a probability whose dominant input is a placeholder is visibly that.

What evidence is this built on?

20 polls, most recent 2026-08-19. 10% verified against a primary source.

What changed since the last run?

Shaded band is the 90% interval, line is the central estimate, positive is Katie Hobbs ahead of Andy Biggs. Over 15 stored forecasts the central estimate moved +0.8 points. There were 7 specification changes (marked on the axis) and no new polls arrived over this window — so every movement in this chart is a change to the model, not a change in the race.

Since 2026-10-01: margin +0.00 points, win probability +0.0 points, on +0 polls.

Not answered here: why it changed. Splitting a move into new polls, time and specification means re-running the earlier model against the later inputs -- two extra posterior fits -- so it is computed on a cadence (scripts/attribute_forecasts.py) rather than while you wait. This pair of runs has not been decomposed yet. The size of the move is shown; the cause is not guessed at.

How has this model done before?

Measured on 230 forecasts across 230 races in cycles 2016,2018,2020,2022,2024: mean absolute error 4.56 points, Brier score 0.0543. The nominal 90% interval contained the result 94% of the time, the 80% interval 84%, and the 50% interval 47%. Read that with care: a national polling miss moves every race in a cycle at once, so the sample size for a question about the intervals is 5 cycle(s), not 230 forecasts. Per cycle -- bias +1.644 pts; 2016: n=43 bias=+4.68 cov90=0.860; 2018: n=63 bias=-0.52 cov90=1.000; 2020: n=35 bias=+5.44 cov90=0.886; 2022: n=54 bias=-0.60 cov90=0.944; 2024: n=35 bias=+1.48 cov90=1.000.

Where did every number come from?

Nowcast run 4fa18a27-7e8c-4ea3-985f-7260918d0439 and election-day run 0a5ab157-e2c8-41ff-ba5a-12130f92239d, model single_race_latent/0.8.1 at commit bdf7e83107c17a2399efe61a44ef1bbee48f9284, seeds 20260924 and 20260924.