Who's Hot, Who's Not: Examining Trends in U.S. Senate Races

One way to measure how well a candidate is doing to measure the momentum they are maintaining in their polling.  Rather than try and decipher the individual movements of polls (some battleground states and California have had more than a dozen polls taken since the beginning of June), below is a month-by-month summary of 15 states where significant movement has taken place in at least one month since June.  If a monthly poll shows a party initial with a "+", it denotes that the polls for that party's candidate significantly improved during that month; the opposite is true if a letter has a "-" next to it.  Months with only a dash indicate no significant movement for either party.

                            June     July    Aug   Sept   Current (R-D)   Result
AR                        -           -        R-      -        54-35                Still solid GOP lead
CA                        -           -         -       D+     43-47                Dems pulling ahead
CT                        R+       R+      -        -        45-51                No GOP momentum
DE                        R+       R+      -        -        40-54                Swap: GOP to Dem
FL                         R+       R+     R+     -         39-31               Stable GOP lead
MO                        R+       -        -        -         50-44               No GOP momentum
NV                         -          -        R+     R+      45-45               GOP and Dems tied
NH                         -          -        -        R+      49-37               Solidified GOP lead
NY - Gillibrand       -         R+     R+      -         39-50               Dems w/ solid lead
NY - Schumer        -         R+     -         -         35-57               Dems w/ solid lead
OH                        R+       R+     R+      -        51-38               GOP has solid lead
OR                        D+       -        R+      -        37-54               Dems have solid lead
SC                         R+       -        -         -        64-21               GOP has solid lead
WA                        -          -        -         R+     45-48               GOP closing gap
WI                         R+       R+     R+      -        47-42               Swap: Dem to GOP
                  
The overwhelming majority of the gains in momentum that have been made over the past four months have been on the side of the GOP.  Most of these movements, though, have not been game changers for either party. 

The Democrats have been able to begin to pull away in California and Oregon (despite an August GOP surge there). Likewise, Delaware has gone Democratic.  By comparison, only Wisconsin has changed from blue to red since June. More states may be trending one way or another but not enough surveys have been conducted in the past month to tell for sure. 

At present, six states have races where the parties are within five points of each other: CA (-4.9); IL (+1); KY (+3.4); NV (-0.2); WA (-2.5); and WV (+3.5).  If the election were held today, the results would be evenly split, giving the Democrats a 51-49 margin in the Senate.