Wisconsin · 2026 forecast · Updated Oct 16, 2026

Who will control the Wisconsin State Senate?

17 of 33 seats are on the ballot; the others are elected in alternate years. 17 seats make a majority. 22 make the two-thirds supermajority that can override a veto.

Democrats are very likely to control the Wisconsin State Senate (95%), which would flip it from Republican control.

Democrats

95%

chance of control

Republicans

Avg. D seats: 17.980% range 17–19
Avg. R seats: 15.180% range 14–16
Now: 15 D · 18 R17 up this year

Neither party has a meaningful chance of a two-thirds supermajority (22+ seats): under 1% each.

Democrats are favored to control the Wisconsin State Senate (79%), which would flip it from Republican control.

Democrats

79%

chance of control

Republicans

21%

Avg. D seats: 17.480% range 16–19
Avg. R seats: 15.680% range 14–17
Now: 15 D · 18 R17 up this year

Neither party has a meaningful chance of a two-thirds supermajority (22+ seats): under 1% each.

Solid D
Likely D
Lean D
Toss-up
Lean R
Likely R
Solid R
Holdover, not up this year

Race ratings

All 17 races, grouped by the leader's chance of winning.

3 seats projected to flip: 3 R→D.

Solid D6

Likely D1

SD-21flip

Lean D1

SD-17flip

Toss-up0

Lean R0

Likely R2

Solid R7

Solid D3

Likely D3

Lean D2

Toss-up0

Lean R0

Likely R2

Solid R7

Columns follow the chance of winning: Toss-up 40–60%, Lean 60–80%, Likely 80–95%, Solid 95%+. The square shows who holds the seat now (■ Democrats, ■ Republicans). flip: projected to change parties, in the color of the party favored to gain it. Faded: no major-party opponent.

The map

Each district colored by the leader's chance of winning. Hover for details; click for the race.

Wisconsin

Milwaukee

Solid D
Likely D
Lean D
Toss-up
Lean R
Likely R
Solid R
Projected flip (stripes: party holding it now)

Seats to watch

The closest races (Lean or Toss-up, Horizon), and the seats most likely to change parties.

Closest races

SD-17Jenna JacobsonHoward MarkleinD flipD flip79%Dem.76%Dem.

Most likely to flip

SD-5Robyn ViningMike RobertsD flipD flip97%to flip87%to flip SD-21Trevor JungJim CroftD flipD flip94%to flip77%to flip SD-17Jenna JacobsonHoward MarkleinD flipD flip79%to flip76%to flip SD-25Charly RayErik Severson19%to flip17%to flip SD-29Gillian BattinoCory Tomczyk5%to flip7%to flip SD-31Jeff SmithMichele Magadance Skinner3%to flip20%to flip SD-19Emily TseffosRachael Cabral-Guevara1%to flip2%to flip SD-15Mark SpreitzerScott Fleming1%to flip8%to flip SD-11Adam DudaEllen Schutt<1%to flip1%to flip SD-13Sasha RipleyJohn Jagler<1%to flip1%to flip

How this chamber is elected

Rules that shape these races and the forecast.

Staggered Senate

Senators serve four-year terms; the odd-numbered districts are on the ballot in midterm years and the even-numbered ones in presidential years.

17 of 33 seats on the ballot; 16 holdovers (10 D, 6 R) serve until a later election.

How the odds have moved

Chance of winning control, by forecast date.

Updated nightly. Each day is the current model run on the polls that had ended by then (how).

Every outcome we simulated

Democratic seats across 40,000 simulations. Darker bars: the middle 80%.

Every race

17 races, 4 without a contest between the major parties.

17 races

District	Candidates	Chance of winning (D · R)	Avg. margin	Rating	Lean	Polls
SD-1	● No Democrat● Nic CravillionAlso: Mark Becker (I)	No Democrat on the ballotNo Democrat on the ballot	—	Solid R (no Democrat)Solid R (no Democrat)	R+21	—
SD-3	● Tim CarpenterINC● No Republican	Democrat unopposedDemocrat unopposed	—	Uncontested DUncontested D	D+30	—
SD-5D flipD flip	● Robyn Vining● Mike Roberts	97%3% 87%13%	D+14.5D+10.8	Solid DLikely D	D+5	—
SD-7	● Chris LarsonINC● Mike Moeller	>99%<1% >99%<1%	D+36.9D+35.0	Solid DSolid D	D+30	—
SD-9	● No Democrat● Amy BinsfeldAlso: Christian Ellis (I)	No Democrat on the ballotNo Democrat on the ballot	—	Solid R (no Democrat)Solid R (no Democrat)	R+16	—
SD-11	● Adam Duda● Ellen Schutt	<1%>99% 1%99%	R+21.9R+23.1	Solid RSolid R	R+28	—
SD-13	● Sasha Ripley● John JaglerINC	<1%>99% 1%99%	R+22.6R+25.8	Solid RSolid R	R+31	—
SD-15	● Mark SpreitzerINC● Scott FlemingAlso: Christopher Dean (I)	99%1% 92%8%	D+19.0D+13.5	Solid DLikely D	D+9	—
SD-17D flipD flip	● Jenna Jacobson● Howard MarkleinINC	79%21% 76%24%	D+5.9D+6.7	Lean DLean D	D+2	—
SD-19	● Emily Tseffos● Rachael Cabral-GuevaraINC	1%99% 2%98%	R+17.9R+20.9	Solid RSolid R	R+26	—
SD-21D flipD flip	● Trevor Jung● Jim Croft	94%6% 77%23%	D+11.6D+6.7	Likely DLean D	D+1	—
SD-23	● Jeff Foster● Romaine Quinn	<1%>99% <1%>99%	R+28.0R+31.0	Solid RSolid R	R+36	—
SD-25	● Charly Ray● Erik Severson	19%81% 17%83%	R+6.4R+9.1	Likely RLikely R	R+13	—
SD-27	● Dianne HesselbeinINC● No Republican	Democrat unopposedDemocrat unopposed	—	Uncontested DUncontested D	D+54	—
SD-29	● Gillian Battino● Cory TomczykINC	5%95% 7%93%	R+12.1R+14.4	Likely RLikely R	R+19	—
SD-31	● Jeff SmithINC● Michele Magadance Skinner	97%3% 80%20%	D+14.9D+7.9	Solid DLikely D	D+3	—
SD-33	● Mike Van Someran● Chris KapengaINC	<1%>99% 1%99%	R+25.6R+29.0	Solid RSolid R	R+34	—

Lean: how much more Democratic (D+) or Republican (R+) the place voted for president than the nation (2024 weighted 75%, 2020 25%). Ratings follow the chance of winning: Toss-up 40–60%, Lean 60–80%, Likely 80–95%, Solid 95%+. INC = incumbent running. D flip / R flip: another party is favored (60% or more) over the party holding the seat now (hover for the chance it changes parties); Flip risk: the seat is a toss-up (40–60%).