Most often in May, 22 days.
Highest follower count seen that year: 14,695.
January
Jan 2 20:00–24:00 Jan 3 00:00–04:00, 20:00–24:00 Jan 4 00:00–05:00, 20:00–24:00 Jan 5 00:00–04:00, 20:00–24:00 Jan 6 00:00–04:00 Jan 9 21:00–24:00 Jan 10 00:00–04:00, 20:00–24:00 Jan 11 00:00–04:00, 20:00–24:00 Jan 12 00:00–04:00, 20:00–24:00 Jan 13 00:00–05:00 Jan 16 20:00–24:00 Jan 17 00:00–04:00, 20:00–24:00 Jan 18 00:00–04:00, 20:00–24:00 Jan 19 00:00–04:00, 20:00–24:00 Jan 20 00:00–05:00 Jan 23 21:00–22:00 Jan 24 02:00–04:00, 20:00–24:00 Jan 25 00:00–04:00, 20:00–24:00 Jan 26 00:00–06:00, 20:00–22:00 Jan 30 20:00–24:00 Jan 31 00:00–04:00, 20:00–24:00
February
Feb 1 00:00–04:00, 20:00–24:00 Feb 2 00:00–05:00, 20:00–22:00 Feb 6 18:00–24:00 Feb 7 00:00–02:00, 20:00–24:00 Feb 8 00:00–05:00, 20:00–24:00 Feb 9 00:00–04:00, 20:00–24:00 Feb 10 00:00–04:00 Feb 13 20:00–24:00 Feb 14 00:00–04:00, 20:00–24:00 Feb 15 00:00–05:00, 20:00–24:00 Feb 16 00:00–04:00, 21:00–24:00 Feb 17 00:00–04:00 Feb 20 20:00–24:00 Feb 21 00:00–04:00, 20:00–24:00 Feb 22 00:00–04:00, 20:00–24:00 Feb 23 00:00–04:00, 20:00–24:00 Feb 24 00:00–04:00 Feb 27 20:00–24:00 Feb 28 00:00–04:00, 20:00–24:00
March
Mar 1 00:00–04:00, 20:00–24:00 Mar 2 00:00–03:00, 20:00–24:00 Mar 3 00:00–04:00 Mar 13 20:00–24:00 Mar 14 00:00–04:00, 20:00–24:00 Mar 15 00:00–04:00, 20:00–23:00 Mar 16 17:00–24:00 Mar 17 00:00–04:00 Mar 20 20:00–24:00 Mar 21 00:00–04:00, 20:00–24:00 Mar 22 00:00–04:00, 20:00–24:00 Mar 23 00:00–04:00, 21:00–24:00 Mar 24 00:00–05:00 Mar 27 20:00–24:00 Mar 28 00:00–04:00, 20:00–24:00 Mar 29 00:00–04:00, 21:00–24:00 Mar 30 00:00–04:00, 20:00–24:00 Mar 31 00:00–04:00
April
Apr 4 20:00–24:00 Apr 5 00:00–04:00 Apr 6 21:00–23:00 Apr 7 00:00–04:00 Apr 10 20:00–24:00 Apr 11 00:00–05:00, 21:00–24:00 Apr 12 00:00–05:00, 17:00–24:00 Apr 13 00:00–04:00, 20:00–24:00 Apr 14 00:00–05:00 Apr 17 20:00–24:00 Apr 18 00:00–04:00, 20:00–24:00 Apr 19 00:00–04:00 Apr 20 21:00–24:00 Apr 21 00:00–04:00 Apr 25 20:00–24:00 Apr 26 00:00–04:00, 21:00–24:00 Apr 27 00:00–04:00, 21:00–23:00
May
May 1 20:00–24:00 May 2 00:00–04:00, 21:00–24:00 May 3 00:00–04:00, 20:00–24:00 May 4 01:00–02:00, 20:00–23:00 May 8 20:00–24:00 May 9 00:00–04:00, 20:00–24:00 May 10 00:00–04:00, 20:00–24:00 May 11 00:00–04:00, 20:00–24:00 May 12 03:00–04:00 May 15 20:00–24:00 May 16 00:00–04:00, 20:00–24:00 May 17 00:00–04:00, 20:00–24:00 May 18 00:00–04:00, 20:00–24:00 May 19 01:00–04:00 May 22 20:00–24:00 May 23 00:00–04:00, 20:00–24:00 May 24 00:00–04:00, 20:00–24:00 May 25 00:00–04:00, 20:00–24:00 May 26 00:00–04:00 May 29 20:00–24:00 May 30 00:00–04:00, 21:00–24:00 May 31 00:00–04:00, 21:00–24:00
June
Jun 1 00:00–05:00, 20:00–24:00 Jun 2 00:00–04:00
July
Jul 10 20:00–24:00 Jul 11 00:00–01:00, 20:00–24:00 Jul 12 00:00–02:00, 21:00–24:00 Jul 13 00:00–04:00, 21:00–24:00 Jul 14 00:00–01:00 Jul 17 22:00–24:00 Jul 18 00:00–03:00, 21:00–24:00 Jul 19 00:00–03:00, 21:00–24:00 Jul 20 00:00–02:00 Jul 24 21:00–24:00 Jul 25 00:00–01:00, 21:00–24:00 Jul 26 00:00–02:00, 21:00–24:00 Jul 27 00:00–02:00, 21:00–23:00 Jul 31 21:00–24:00
August
Aug 1 00:00–03:00, 20:00–23:00 Aug 2 21:00–24:00 Aug 3 00:00–03:00, 21:00–24:00 Aug 4 00:00–01:00 Aug 22 21:00–24:00 Aug 23 01:00–03:00, 21:00–24:00 Aug 24 00:00–02:00, 21:00–24:00 Aug 25 00:00–02:00 Aug 28 20:00–24:00 Aug 29 00:00–01:00, 21:00–24:00 Aug 30 00:00–01:00, 21:00–24:00
September
Sep 4 20:00–24:00 Sep 5 00:00–02:00, 21:00–24:00 Sep 6 00:00–03:00, 21:00–24:00 Sep 7 00:00–04:00, 21:00–24:00 Sep 8 00:00–01:00 Sep 12 21:00–24:00 Sep 13 00:00–03:00, 21:00–24:00 Sep 14 00:00–02:00, 21:00–24:00 Sep 15 00:00–01:00 Sep 27 20:00–24:00 Sep 28 00:00–03:00, 20:00–24:00 Sep 29 00:00–01:00
October
Oct 3 21:00–24:00 Oct 4 00:00–02:00, 21:00–24:00 Oct 5 00:00–03:00, 20:00–24:00 Oct 6 00:00–01:00 Oct 10 21:00–24:00 Oct 11 01:00–03:00 Oct 12 21:00–24:00 Oct 13 00:00–02:00 Oct 16 21:00–24:00 Oct 17 00:00–02:00, 21:00–24:00 Oct 18 00:00–02:00 Oct 19 21:00–24:00 Oct 20 00:00–02:00 Oct 23 21:00–24:00 Oct 24 21:00–24:00 Oct 25 00:00–02:00, 21:00–24:00 Oct 26 00:00–02:00 Oct 30 22:00–24:00 Oct 31 00:00–02:00, 22:00–24:00
November
Nov 1 00:00–04:00, 22:00–24:00 Nov 2 00:00–03:00, 21:00–24:00 Nov 11 06:00–11:00 Nov 12 06:00–11:00 Nov 13 06:00–10:00 Nov 14 06:00–11:00, 22:00–24:00 Nov 15 00:00–01:00, 21:00–24:00 Nov 16 00:00–01:00 Nov 17 06:00–09:00 Nov 18 06:00–10:00 Nov 19 06:00–09:00 Nov 20 06:00–10:00 Nov 22 20:00–24:00 Nov 23 00:00–02:00 Nov 25 06:00–10:00 Nov 27 06:00–11:00 Nov 28 06:00–10:00, 20:00–24:00 Nov 29 00:00–01:00
December
Dec 9 06:00–10:00 Dec 12 21:00–24:00 Dec 13 00:00–02:00, 21:00–24:00 Dec 14 00:00–01:00, 21:00–24:00 Dec 15 00:00–02:00 Dec 22 21:00–24:00 Dec 23 00:00–01:00, 20:00–24:00 Dec 24 21:00–24:00 Dec 25 00:00–02:00, 21:00–23:00 Dec 27 20:00–24:00 Dec 28 00:00–01:00, 20:00–23:00