September 22, 2020
FiveThirtyEight recently added a Senate forecast to its website. As of this writing, their model gives Democrats a 62% probability of winning control. The most likely outcomes are a 50-50 split, followed by a 51-49 Democratic margin. In a 50-50 split, the outcome of the presidential election will determine Senate control. The 62% figure is therefore somewhat influenced by the site's presidential forecast.
We've created an interactive map based on this model. It will update every two hours, reflecting the then-current probabilities associated with each race. Click or tap the image below for full details and to use it as a starting point to create and share your own 2020 Senate forecast.