(In no way do I glorify the actions of these people) Some information may be incorrect as some sources were saying different things if you notice a mistake please contact me, thanks.
JANUARY
Clifford Olson - 1st January 1940 (Convicted 11 murders)
Ian Brady - 2nd January 1938 (Convicted of 5 murders)
Phillip Carl Jablonski - 3rd January 1946 (Convicted of killing 5 women)
Vincent Johnson "The Brooklyn Strangler" - 6th January 1969 (Convicted of 5 murders)
Israel Keyes - 7th January 1978 (4 confirmed murders)
William Bonin "The Freeway Killer"- 8th January 1947 (convicted of 14 murders, suspected 36
Ronald Dominique - 9th January 1964 (Admitted to 23 murders)
Dorothea Puente "Death House Landlady" - 9th January 1929 (9 confirmed, possible 15)
George Joseph Smith "Brides in the Bath Murderer" - 11th January 1872 (Victims 3)
Dr. Harold Shipman "Dr. Death" - 14th January 1946 (Victims 215+)
Wang Qiang - 16th January 1975 (Victims 45+)
Vasily Kulik - 17th January 1956 (Victims 13+)
Claude Lastennet - 19th January 1971 (Convicted of 5 murders)
Altemio Sanchez “The Bike Path Killer” - 19th January 1958 (Convicted of 3 murder charges and rape of 9-15 girls.
Joel Rifkin "Joel the Ripper" - 20th January 1959 (Believed to of killed at least 17)
Daniel Camargo Barbosa - 22nd January 1930 (Believed to of killed 150) Romulus Veres - 23rd January 1929 (Charged with 5 murders and several attempts)
Luis Alfredo Garavito Cubillos "The Beast" - 25th January 1957 (138 confirmed, claimed 300)
Lam Kwok-wai - 27th January 1971 (Convicted of 3 murders and 10 rapes)
Yoshio Kodaira - 28th January 1905 (Convicted of 8 murders)
Erwin Hagedorn - 30th January 1952 (Convicted of 3 murders)
Robert Berdella "The Kansas City Butcher" - 31st January 1949 (Convicted of at least 6 murders)
Jerry Brudos "The Lust Killer" - 31st January 1939 (Convicted of 4 murders)
FEBRUARY Very Idham Henyansyah - 1st February 1978 (Confessed to killing 11 people)
Tiago Henrique Gomes da Rocha - 4th February 1988 (39 claimed victims)
Eugen Weidmann - 5th February 1908 ( Murdered 6)
Billy Gohl - 6th February 1873 (2 victims possible 100+) Mohammed Bijeh - 7th February 1982 (Confessed to 16 murders) Juan Corona - 7th February 1934 (Convicted of 25 murders)
Howard Allen - 10 February 1949 (Convicted of 3 murders) Karl Denke - 11th February 1860 (Convicted of 30-42+ victims ) Allan Legere - 13th February 1948 (Convicted of 5+ victims ) Robert Hansen - 15th February 1939 (Murdered at least 17)
David John Birnie - 16th February 1951 (Convicted of the murder of 4 women)
Gary Ridgeway - 18th February 1949 (Convicted of 48 murders)
Stephen Morin - 19th February 1951 (Convicted of 4-48 Victims) Stephen Port - 22nd February 1975 (Convicted of at least 4 killings) Eric Edgar Cooke - 25th February 1931 (Convicted of 8 murder and 14 attempted murder)
Willam Patrick Fyfe - 27th February 1955 (Convicted of 9-25 Victims) Pedro Pablo Nakada Ludeña - 28th February 1973 (Convicted of 17, claimed 25) Richard Ramirez - 29th February 1960 (Convicted of 14 murders)
Aileen Wuornos - 29th February 1956 (Convicted of 7 murders) MARCH Joseph Roy Metheny - 2nd March 1955 (Convicted of 2-13 victims) Robert Joseph Silveria Jr - 3rd March 1959 ( Convicted of 9-14+ Victims) Peter Woodcock - 5th March 1939 (Convicted of 4 murders) Ottis Toole - 5th March 1947 (Convicted of 6 murders) Faryion Wardnip - 6th March 1959 (Convicted of 5 murders) Adolf Seefeldt - 6th March 1870 (Convicted of 12 murders) Mikhail Popkov - 7th March 1964 (Convicted of 78, confessed to 83) Dennis Rader - 9th March 1945 (Convicted of 10 murders) Doug Clark - 10th March 1948 (Convicted of 6+ murders) Donald Henry Gaskins - 13th March 1933 (Convicted of 9, claimed 110) Peter Manuel - 13th March 1927 (Convicted of 7+ murders) Morris Solomon Jr. - 15th March 1944 (Convicted of 6 murders, possible 7) Colin Ireland - 16th March 1954 (Convicted of 5 murders) John Wayne Gacy - 17th March 1942 (Convicted of 33+ murders) Randy Kraft - 19th March 1945 (Convicted of 16+ murders) Andre Crawford - 20th March 1962 (Convicted of 11 murders) Darren Deon Vann - 21st March 1971 (Convicted of 7, possible 18) Joseph L. Taborsky - 23rd March 1924 (Convicted of 7 murders) Gerard John Schaefer - 25th March 1946 (Convicted of 2-30+ murders)
Robert Shulman - 28th March 1954 (Convicted of 5 murders) John Martin Crawford - 29th March 1962 (Convicted of 4+ murders) APRIL Alexander Bychkov - 1st April 1988 (Convicted of 9-11 murders) Leslie Irvin - 2nd April 1924 (Convicted of 6+ murders) Roberto Succo - 3rd April 1962 (Convicted of 7 murders)
Michel Fourniret - 4th April 1942 (Convicted of 8-12+ murders) Alfredo Galán Sotillo - 5th April 1978 (Convicted of 6 murders) Keith Hunter Jesperson - 6th April 1955 (Convicted of 8 confirmed murders) Charles Sobhraj - 6th April 1944 (Convicted of 12+ murders)
Gennady Mikhasevich - 7th April 1947 (Convicted of 33 murders) Herb Baumeister - 7th April 1947 (8-16 victims died before trial) John Christie - 8th April 1899 (Convicted of 8+ murders) Alexander Pichushkin - 9th April 1974 (Convicted of 48-60 murders) Richard Kuklinski - 11th April 1935 (Convicted of 5 murders) Henri Désiré Landru - 12th April 1869 (Convicted of 11 murders) Joseph Paul Franklin - 13th April 1930 (Convicted of 8 murders 20+ suspected) Paul Denyer - 14th April 1972 (Convicted of 3 murders) Donald Harvey - 15th April 1952 (Convicted of 37-87 murders) Paul John Knowles - 17th April 1946 (Convicted of 20-35+ murders)
Joachim Kroll - 17th April 1933 (Convicted of 8, confessed to 14)
Yoo Young-chul - 18th April 1970 (Convicted of 20 murders)
Robert Black - 21st April 1947 (Convicted of 4+ murders)
Vladimir Mukhankin - 22nd April 1960 (Convicted of 9 murders)
Dagmar Overbye - 23rd April 1887 (Convicted of 9-25 murders)
Steve Wright - 24th April 1958 (Convicted of 5+ victims)
MAY David Carpenter - 6th May 1930 (Convicted of 7-11 victims) Carroll Cole - 9th May 1938 (Convicted of at least 16 murders) Earle Nelson - 12th May 1897 (Convicted of 22+ murders) Waneta Hoyt - 13th May 1946 (Convicted of killing 5 of her children) Dorángel Vargas - 14th May 1957 (Convicted of 14 murders) Milton Johnson - 15th May 1950 (Convicted of 10+ murders) H. H. Holmes - 16th May 1861 (Convicted of 9 confirmed, confessed 27, but suspected to be 200)
Levi Bellfield - 17th May 1968 (Convicted of 3+ murders) Harvey Carignan - 18th May 1927 (Convicted of 5+ murders) Albert Fish - 19th May 1870 (Convicted of 3 confirmed; 9–100+ claimed) Jeffrey Dahmer - 21st May 1960 (Convicted of 17 murders) Kenneth Bianchi - 22nd May 1951 (Convicted of 12 murders) Richard Chase - 23rd May 1950 (Convicted of 6 murders) Lorenzo Gilyard - 24th May 1950 (Convicted of 6, suspected of 13 murders) Peter Kürten - 26th May 1883 (Convicted of 9+, Attempted murder: 31+) Robert Lee Yates - 27th May 1952 (Convicted of 16+ murders) Wayne Williams - 27th May 1958 (Convicted of 2 murders, suspected to have murdered at least 23+) Silvo Plut - 29th May 1968 (Convicted of 3 murders) Anthony Hardy - 31st May 1951 (Convicted of 3-9+ murders) JUNE David Berkowitz - 1st June 1953 (Convicted of 6 murders) András Pándy - 1st June 1927 (Convicted of 6-14+ murders) Peter Sutcliffe - 2nd June 1946 (Convicted of 13 murders) Arthur Shawcross - 6th June 1945 (Convicted of 14 murders) Samuel Little - 7th June 1940 (Convicted 60 murders, 93 confessed) David Meirhofer - 8th June 1949 (Convicted of 4 murders) Trevor Hardy - 11th June 1945 (Convicted of 3 murders) Rory Enrique Conde - 14th June 1965 (Convicted of 6 murders) Sean Vincent Gillis - 24th June 1962 (Convicted of 8 murders) Anthony Allen Shore - 25th June 1962 (Convicted of 4-5 murders) Robert Maudsley - 26th June 1953 (Convicted of 4 murders) Leonard Fraser - 27th June 1951 (Convicted 4-7+ murders) Carl Panzram - 28th June 1891 (22 confessed, 5 confirmed) Matthew James Harris - 30th June 1968 (Convicted of 3 murders) JULY Elisabeth Wiese - 1st July 1853 (Convicted of 5 murders) John Joubert - 2nd July 1963 (Convicted of 3 murders) Westley Allan Dodd - 3rd July 1961 (Convicted of 3 murders) Donald Leroy Evans - 5th July 1957 (Convicted of 3–70+ murders) Peter Dupas - 6th July 1953 (Convicted of 3-6 murders)
Rudolf Pleil - 7th July 1924 (Convicted of 10-25 murders) Charles Schmid - 8th July 1942 (Convicted of 3 murders) Thomas Dillon - 9th July 1950 (Convicted of 5 murders) Donato Bilancia - 10th July 1951 (Convicted of 17 murders) Michael Wayne McGray - 11th July 1965 (Convicted 7-18+ murders) Billy Glaze - 13th July 1943 (Convicted of 3-20+ murders) Julio Pérez Silva - 15th July 1963 (Convicted of 14 murders) Charles Ray Hatcher - 16th July 1929 (Convicted of 2, confessed to 16) Pedro Rodrigues Filho - 17th July 1954 (Convicted of 71–100+) Myra Hindley - 23rd July 1942 (Convicted of 5 murders) John Haigh - 24th July 1909 (Convicted of 6-9 murders) Anatoly Onoprienko - 25th July 1959 (Convicted of 52 murders) Joseph Christopher - 26th July 1955 (Convicted of 12+ murders) Bela Kiss - 28th July 1877 (Convicted of 24+ murders)
Yang Xinhai - 29th July 1968 (Convicted of 67 murders)
Heriberto Seda - 31st July 1967 (Convicted of 3 murders)
Bruce George Peter Lee - 31st July 1960 (Convicted of 15 murders)
AUGUST Ángel Maturino Reséndiz - 1st August 1959 (Convicted of 23 murders) Donald Neilson - 1st August 1936 (Convicted of 4 murders) Tony Costa - 2nd August 1944 (Convicted of 4-8 murders) Zhang Jun - 5th August 1966 (Convicted of 28 murders) Hiroshi Maeue - 8th August 1968 (Convicted of 3 murders) Dallen Bounds - 9th August 1971 (Convicted of 4+ murders) Charles Albright - 10th August 1933 (Convicted of 1, 2 more suspected) Paul Durousseau - 11th August 1970 (Convicted of 7 murders) Willem van Eijk - 13th August 1941 (Convicted of 5 murders) Jack Unterweger - 16th August 1950 (Convicted of 12-15 murders) Anthony Sowell - 19th August 1959 (Convicted of 11 murders) William Suff - 20th August 1950 (Convicted of 12-22 murders) Tsutomu Miyazaki - 21st August 1962 (Convicted of 4 murders) Rodney Alcala - 23rd August 1943 (Convicted of 8-130 murders) Henry Lee Lucas - 23rd August 1936 (Convicted of 11 murders) Richard Biegenwald - 24th August 1940 (Convicted 6-8+ murders) Benjamin Atkins - 26th August 1968 (Convicted of 11 murders) Kiyotaka Katsuta - 29th August 1948 (Convicted of 8-22 murders) Lonnie David Franklin Jr - 30th August 1952 (Convicted of 10-25+ murders) SEPTEMBER John Cooper - 3rd September 1944 (Convicted of 4 murders) John Bunting - 4th September 1966 (Convicted of 11 murders) Paul Steven Haigh - 5th September 1957 (Convicted of 7 murders) Mark Goudeau - 6th September 1964 (Convicted of 9 murders) Graham Young - 7th September 1947 (Convicted of 3+ murders) Joachim Knychała - 8th September 1952 (Convicted of 5 murders) Paul Michael Stephani - 8th September 1944 (Convicted of 3 murders and 2 attempted) Harrison Graham - 9th September 1959 (Convicted of 7 murders) Marybeth Tinning - 11th September 1942 (Couldn't find an exact amount, most sources said 2-9 murders) Anthony Kirkland - 13th September 1968 (Convicted of 5 murders) Norbert Poehlke - 15th September 1951 (Convicted of 6 murders) Terry Blair - 16th September 1961 (Convicted of 7 murders) Stephan Letter - 17th September 1978 (Convicted of 29+ murders) Louise Peete - 20th September 1880 (Convicted of 3+ murders) Scott Lee Kimball - 21st September 1966 (Convicted of 4+ murders) Brian Dugan - 23rd September 1956 (Convicted of 3 murders) Patrick Kearney - 24th September 1939 (Convicted of 21-43 murders) Patrick Mackay - 25th September 1952 (Convicted of 3-11 murders) Paul Ogorzow - 29th September 1912 (Convicted of 8+ murders) Fred West - 29th September 1941 (Convicted of 12-13+ murders)
Dayton Leroy Rogers - 30th September 1953 (Convicted of 7-8+ murders) Luis Gregorio Ramírez Maestre - 30th September 1980 (Couldn't find an exact amount as there isn't much about him) OCTOBER Peter Bryan - 4th October 1969 (Convicted of 3 murders) Angelo Buono Jr. - 5th October 1934 (Convicted of 10 murders) Jeanne Weber - 7th October 1874 (Convicted of 6 murders)
Pedro López - 8th October 1948 (Convicted of 110 murders, claimed 300) Kang Ho-sun - 10th October 1969 (Convicted of 10 murders) Craig Price - 11th October 1973 (Convicted of 4 murders) Ion Rîmaru - 12th October 1946 (Convicted of 4 murders) Bobby Joe Long - 14th October 1953 (Convicted of 10 murders) Guy Georges - 15th October 1962 (Convicted of 7th murders) Michael Madison- 15th October 1977 (Convicted of 3 murders) Manuel Octavio Bermúdez - 15th October 1961 (Convicted of 21-50+ murders) Andrei Chikatilo - 16th October 1936 (Convicted of 52 murders and claimed 56+) Zdzisław Marchwicki - 18th October 1927 (Convicted of 14 murders) Václav Mrázek - 22nd October 1925 (Convicted of 7 murders) Velma Barfield - 29th October 1932 (Convicted of 6 murders) Robert Pickton - 24th October 1949 (Convicted 6-49 murders) Fritz Haarmann - 25th October 1879 (Convicted of 24-27+ murders) Leonard Lake - 29th October 1945 (Convicted of 11, suspected 25) Cayetano Santos Godino - 31st October 1896 (Convicted of 4 murders) Michel Fourniret - 31st October 1942 (Convicted of 8-12+ murders) NOVEMBER Genzo Kurita - 3rd November 1926 (Convicted of 8 murders) Nannie Doss - 4th November 1905 (Convicted of 11 murders) Chester Turner - 5th November 1966 (Convicted of 14 murders) Derrick Todd Lee - 5th November 1968 (Convicted of 7+ murders) Carl Eugene Watts - 7th November 1953 (Convicted of 14, suspected to be 100 murders) Joseph James DeAngelo - 8th November 1945 (Convicted of 13 murders) Gordon Northcott - 9th November 1906 (Convicted of 3 murders) Belle Gunness - 11th November 1859 (Convicted of 14 murders) Paul Dennis Reid - 12th November 1957 (Convicted of 7 murders) Nikolai Dzhumagaliev - 15th November 1952 (Convicted of 10+ murders) Moses Sithole - 17th November 1964 (Convicted 38, 76 possible) Huang Yong - 18th November 1974 (Convicted 17-25 murders) Florisvaldo de Oliveira - 18th November 1958 (Convicted of 50 murders) Robert Ben Rhoades - 22nd November 1945 (Convicted of 3-50+ murders) Dennis Nilsen - 23rd November 1945 (Convicted 12-15 murders) Ted Bundy - 24th November 1946 (Convicted/confessed of 30 murders)
Richard Cottingham - 25th November 1946 (Convicted of 9 confirmed murders, 85-100 claimed) John Wayne Glover - 26th November 1932 (Convicted 6-13 murders) Thierry Paulin - 28th November 1963 (Convicted of 18-21 murders) Francisco de Assis Pereira - 29th November 1967 (Convicted of 11 murders) Rosemary West - 29th November 1953 (Convicted of 10 murders) DECEMBER José Antonio Rodríguez Vega - 3rd December 1957 (Convicted of 16+ murder) Harvey Miguel Robinson - 6th December 1974 (Convicted of 3 murders) Harvey Glatman - 10th December 1927 (Convicted of 3 murders) Dámaso Rodríguez Martín - 11th December 1944 (Convicted of 3 murders) Gilbert Paul Jordan - 12th December 1931 (Convicted of 1, linked to 8-10 murders) Ahmad Suradji - 12th December 1952 (Convicted of 42 murders) Yvan Keller - 13th December 1960 (Convicted of 23-150 murders)
Steven Grieveson - 14th December 1970 (Convicted of 4+ murders)
Koos Hertogs - 16th December 1949 (Convicted of 3 murders)
Ondrej Rigo - 17th December 1955 (Convicted of 9 murders)
Edmund Kemper - 18th December 1948 (Convicted 10 murders)
Larry Eyler - 21st December 1952 (Convicted of 21-24 murders)
Scott Erskine - 22nd December 1962 (Convicted of 3+ murders)
Dean Corll - 24th December 1939 (Convicted of 28+ murders)
Aleksandr Rubel - 25th December 1980 (Convicted of 6-7 murders)
Randall Woodfield - 26th December 1950 (Connected to 18 murders)
Juana Barraza - 27th December 1957 (Convicted of 42-48 murders)
Anatoly Slivko - 28th December 1938 (Convicted of 7 murders)
Sergei Ryakhovsky - 29th December 1962 (Convicted of 18+ murders)
John Allen Muhammad - 31st December 1960 (Convicted of 10 murders)
Well done mia