Below is a list of key dates relating to the 2008 election season. Deadlines, elections, and events that are specifically relevant to California voters are highlighted in blue text.
| January 2008 |
| January 3 |
Iowa caucuses |
| January 5 |
Wyoming caucuses (Republican) |
| January 6 |
Back-to-back Democratic and Republican debates hosted by ABC, WMUR-TV and Facebook in Manchester, New Hampshire |
| January 7 |
First day to apply for an absent voter's ballot by mail for the February 5 California presidential primary election |
| January 8 |
New Hampshire primary |
| January 10 |
Republican debate hosted by the South Carolina Republican Party and Fox News Channel in Myrtle Beach, S.C. |
| January 15 |
- Michigan primary
- Democratic debate hosted by the Nevada Democratic Party and MSNBC in Las Vegas, NV
|
| January 19 |
- Nevada caucuses
- South Carolina primary (Republican)
|
| January 21 |
Democratic debate hosted by CNN and the Congressional Black Caucus in Myrtle Beach, S.C. |
| January 22 |
Last day to register to vote in the February 5 California presidential primary election |
| January 24 |
Republian debate hosted by Fox News in Boca Raton, FL |
| January 25 - February 7 |
Hawaii caucuses (Republican) |
| January 26 |
South Carolina primary (Democratic) |
| January 29 |
- Last day to submit an application for an absent voter's ballot for the February 5 California presidential primary election
- Florida primary
|
| January 30 |
Republican debate hosted by CNN, the Los Angeles Times, and Politico in Simi Valley |
| January 31 |
Democratic debate hosted by the Los Angeles Times and CNN in Los Angeles |
| February 2008 |
| February 1 |
Maine caucuses (Republican) |
| February 5 |
- California presidential primary (polls open throughout the state from 7 a.m. to 8 p.m.)
- Alabama primary
- Alaska caucuses
- American Samoa caucuses (Democratic)
- Arizona primary
- Arkansas primary
- Colorado caucuses
- Connecticut primary
- Delaware primary
- Georgia primary
- Idaho caucuses (Democratic)
- Illinois primary
- Kansas caucuses (Democratic)
- Massachusetts primary
- Minnesota caucuses
- Missouri primary
- Montana caucuses (Republican)
- New Jersey primary
- New Mexico caucuses (Democratic)
- New York primary
- North Dakota caucuses
- Oklahoma primary
- Tennessee primary
- Utah primary
- West Virginia Republican convention
- Democrats Abroad primary
|
| February 9 |
- Kansas caucuses (Republican)
- Louisiana primary
- Nebraska caucuses (Democratic)
- Washington caucuses
- Virgin Islands Democratic territorial convention
|
| February 10 |
Maine caucuses (Democratic) |
| February 12 |
- District of Columbia primary
- Maryland primary
- Virginia primary
|
| February 16 |
Guam Republican state convention |
| February 19 |
- Hawaii caucuses (Democratic)
- Washington primary
- Wisconsin primary
|
| February 21 |
Democratic debate hosted by CNN, Univision, and the Texas Democratic Party in Austin, Texas |
| February 23 |
American Samoa caucuses (Republican) |
| February 26 |
Democratic debate hosted by NBC News and WKYC in Cleveland, Ohio |
| February 28 |
Republican debate hosted by CNN and the Republican Party of Ohio |
| March 2008 |
| March 4 |
- Ohio primary
- Rhode Island primary
- Texas primary
- Vermont primary
|
| March 8 |
Wyoming caucuses (Democratic) |
| March 10 |
American Samoa caucuses(Democratic) |
| March 11 |
Mississippi primary |
| April 2008 |
| April 5 |
Virgin Islands caucuses (Republican) |
| April 16 |
Democratic debate hosted by ABC News in Philadelphia, Pennsylvania |
| April 22 |
Pennsylvania primary |
| May 2008 |
| May 3 |
Guam Democratic territorial convention |
| May 6 |
- Indiana primary
- North Carolina primary
|
| May 13 |
- Nebraska primary (Republican)
- West Virginia primary
|
| May 17 |
Hawaii Republican state convention |
| May 19 |
Last day to register to vote in the June 3 California Direct Primary Election |
| May 20 |
- Kentucky Primary
- Oregon Primary
|
| May 27 |
Idaho primary (Republican) |
| June 2008 |
| June 1 |
Puerto Rico primary |
| June 3 |
- California Direct Primary Election
- Montana Primary (Democratic)
- New Mexico Primary (Republican)
- South Dakota Primary
|
| July 2008 |
| July 12 |
Nebraska caucuses (Republican) |
| August 2008 |
| August 25-28 |
Democratic National Convention in Denver, CO |
| September 2008 |
| September 1-4 |
Republican National Convention in Minneapolis-Saint Paul, MN |
| September 26 |
Presidential Debate on Domestic Policy at the University of Mississippi in Oxford, MS |
| October 2008 |
| October 2 |
Vice Presidential Debate on Domestic and Foreign Policy at Washington University in St. Louis, MO |
| October 7 |
Presidential Debate, Town Meeting at Belmont University in Nashville, TN |
| October 15 |
Presidential Debate on Foreign Policy at Hofstra University in Hempstead, NY |
| October 20 |
Last day to register to vote in the November 4 general election |
| October 28 |
Last day to submit an application for an absent voter's ballot for the November 4 general election |
| November 2008 |
| November 4 |
General election |
