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2024 Senate Forecast and Predictions

Last Updated: Monday, September 16 at 5:21 PM EDT

Our model currently predicts that Republicans have a 70% chance of winning the Senate.

Prediction Updates

Last updated on Sep 2 2024 by Decision Desk HQ

Decision Desk HQ Relaunches Forecast

After a month-long pause due to President Joe Biden’s decision to withdraw his candidacy, the Decision Desk HQ Forecast model is back.

As part of the relaunch we’ve made some changes in our methodology between the two models as it relates to polling specifically in how we are using a blended average of polls with multiple candidates and weighing them against the demographic fundamentals of each race. You can read our full, updated methodology statement here.

As of our relaunch on August 26th, the presidential model shows Kamala Harris with a 55% chance of winning the presidency. This compared to the 56% chance our previous model gave Donald Trump to defeat Joe Biden when Biden dropped out of the race.

Arizona, Georgia, Nevada, Pennsylvania, and Wisconsin remain Toss-ups (but with Harris improving on Biden’s probabilities in each of these states), while Michigan moves from Toss-up to Lean Democratic and North Carolina moves from Lean Republican to Toss-up

In the Senate, Republicans still lead with a 67% chance to take the majority, compared to their 78% chance when Biden led the Democratic ticket (Note: Our senate model has been updated to better reflect the GOP or Democratic party chances of control of the Senate, based on simulated outcomes of the Presidential election. Incorporating this change led to an increase in overall GOP Senate control chances by a few percentage points from the original forecast.).

Control of the House is still a relative toss up, with the GOP having a 56% chance of winning control compared to their 61% chance prior to our pause in the model.

You can compare the full results of our relaunched model with our original Biden-Trump forecasts here.

Senate Seats Forecast

33 of the 100 U.S. Senate seats will be contested in regular elections this November, along with a special election in Nebraska. Like the last Class 1 Senate cycle in 2018, Republicans are considered to have a fundamental advantage, as Democrats are defending 23 of the 33 seats. Among these, three are in states that Donald Trump won in both the 2016 and 2020 elections, while no Republican-held seats are in states won by Joe Biden in 2020. In the last two Senate elections during presidential years (2016 and 2020), only one senator was elected in a state that the opposing presidential nominee won. This map categorizes states by each party’s likelihood of winning, ranging from 'safe' to 'likely' to 'lean' to 'toss-up'.

48

46

2

Democrat

Republican

51

50 + VP for Majority

NMSDCAKYALGAARPAMOCOUTOKTNWYNYINKSIDAKNVILMNIASCMTAZNEWATXOHWIORMSNCVAWVLAMIFLNDMEHI S
CT
DE
DC
MD
MA
NH
NJ
RI
VT

Chance of winning the senate

Our model is updated every day, blending the latest data on polls and fundraising with "fundamental" factors like incumbency and each district's partisan lean. This graph tracks each party’s probability of winning control of the Senate over time.

Senate Seats Projections

Republican: 52

Democrat: 48

This graph tracks each party’s projected seat count in the Senate over time.

Chance of winning each seat

This chart visualizes the current probabilities of each party winning individual races. Circles positioned further to the left indicate a higher likelihood of a Democratic victory, while circles to the right suggest a stronger chance for Republicans. Use the 'DEM' and 'GOP' filters to view states most likely to support the respective parties.

Senate Seats Simulations

These graphs display the distribution of Senate seat counts from 14,000,605 simulations for both Democrats and Republicans. The lighter shaded areas to the left of the dotted line depict scenarios where a party fails to secure a majority, while the darker shaded areas to the right represent majority-winning outcomes. Each bar indicates the percentage of simulations resulting in a specific seat count.

Our model currently projects a 14.5% chance of a 50-50 tie in the Senate.

Featured Races

Explore the latest probabilities in the most competitive presidential, Senate, and House races by selecting any of the races listed below.

Interested to see how the DDHQ/The Hill forecast works? Read our methodology statement.

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