These dates are also found on the PDC's Calendar of Events.  (Printer-friendly version)

Within 2 weeks of becoming a candidate Register the campaign (File a C-1)
January 10 File a C-3 for each deposit made in the previous month and a C-4 report that covers the period through Dec 31
February 12 File a C-3 for each deposit made in the previous month and a C-4 report that covers the period through Jan 31
March 12 File a C-3 for each deposit made in the previous month and a C-4 report that covers the period through Feb 28
April 10 File a C-3 for each deposit made in the previous month and a C-4 report that covers the period through Mar 31
May 10 File a C-3 for each deposit made in the previous month and a C-4 report that covers the period through Apr 30
May 14-18 Declaration of candidacy filing week
June 1 Begin filing C-3 reports weekly, each Monday, for deposits made during previous 7 days (Monday through Sunday)
June 11 File month C-4, if necessary, that covers the period through May 31
June 25 Last day before primary election to change from mini to full reporting without special circumstances
July 17

Candidates appearing on the primary election ballot file a C-4 that covers the period June 1 through July 16.

Candidates not on the primary election ballot file monthly reports in June, July, August, and September.

July 30 - Aug 6 Campaign books open for public inspection
July 31 Candidates appearing on the primary election ballot file a C-4 that covers the period July 17 through July 30
July 31 - Aug 6 Special reports due if candidate receives contributions of $1,000 or more from a single source
AUGUST 7 PRIMARY ELECTION DAY
August 31 Last day before general election to change from mini to full reporting without special circumstances
September 10

Post-primary C-4 due that covers the period July 31 through August 31

Candidates not on the primary election ballot file a report for the month of August

October 16 21-day pre-general C-4 report due - report for the period Sept 1 through Oct 15
October 16 - November 5
  1. Special reports due if candidate receives contributions of $1,000 or more from a single source
  2. Unless the contribution is from the state committee of a bona fide political party, a candidate may not receive contributions from a single source exceeding $5,000 in the aggregate.  
October 29 - November 5 Campaign books open for public inspection
October 30 7-day pre-general C-4 report due - report for the period Oct 16 through Oct 29
November 5 Last Monday that weekly C-3 reports must be filed
NOVEMBER 6 GENERAL ELECTION DAY
December 10 Post-general C-4 due that covers Oct. 30 through Nov 30.  File C-3s that have not been filed for any deposits made in November.
January 10, 2019 End of election cycle C-4 due that covers Dec 1 through Dec 31.  File C-3s for any deposits made in December.