Most often in June, 25 days.
Highest follower count seen that year: 717.
January
Jan 4 01:00–03:00 Jan 5 04:00–06:00 Jan 6 03:00–04:00 Jan 7 02:00–04:00, 23:00–24:00 Jan 8 00:00–01:00 Jan 9 00:00–02:00 Jan 10 00:00–01:00 Jan 12 23:00–24:00 Jan 13 00:00–01:00, 22:00–23:00 Jan 15 00:00–02:00 Jan 16 00:00–01:00 Jan 19 23:00–24:00 Jan 20 22:00–23:00 Jan 21 22:00–23:00 Jan 23 00:00–02:00 Jan 24 02:00–03:00 Jan 25 01:00–02:00 Jan 26 01:00–03:00, 21:00–23:00 Jan 29 00:00–02:00 Jan 31 00:00–02:00
February
Feb 2 06:00–07:00 Feb 3 00:00–02:00, 23:00–24:00 Feb 4 00:00–01:00 Feb 6 00:00–01:00, 23:00–24:00 Feb 7 00:00–01:00 Feb 10 00:00–01:00 Feb 11 00:00–01:00 Feb 12 00:00–01:00 Feb 13 00:00–01:00, 22:00–24:00 Feb 15 05:00–06:00 Feb 16 01:00–03:00 Feb 17 00:00–01:00, 23:00–24:00 Feb 19 00:00–01:00, 23:00–24:00 Feb 20 00:00–01:00 Feb 21 01:00–02:00 Feb 22 02:00–03:00
March
Mar 11 22:00–24:00 Mar 12 22:00–24:00 Mar 13 23:00–24:00 Mar 16 23:00–24:00 Mar 17 22:00–23:00 Mar 19 02:00–03:00 Mar 20 23:00–24:00 Mar 22 01:00–02:00 Mar 23 02:00–04:00, 23:00–24:00 Mar 24 00:00–01:00 Mar 25 22:00–24:00
April
Apr 11 00:00–01:00 Apr 12 23:00–24:00 Apr 13 22:00–23:00 Apr 14 18:00–19:00, 23:00–24:00 Apr 15 22:00–24:00 Apr 16 20:00–21:00 Apr 18 20:00–21:00 Apr 19 01:00–02:00 Apr 21 23:00–24:00 Apr 22 20:00–21:00 Apr 23 23:00–24:00 Apr 24 23:00–24:00 Apr 25 00:00–01:00, 23:00–24:00 Apr 27 00:00–02:00 Apr 29 00:00–01:00, 22:00–23:00
May
May 1 02:00–03:00, 19:00–22:00 May 4 22:00–23:00 May 5 23:00–24:00 May 6 00:00–01:00 May 7 00:00–01:00, 23:00–24:00 May 8 00:00–02:00, 23:00–24:00 May 9 00:00–01:00 May 10 04:00–05:00 May 11 20:00–21:00 May 12 22:00–23:00 May 13 23:00–24:00 May 15 21:00–22:00 May 16 01:00–02:00, 22:00–23:00 May 17 01:00–02:00 May 18 01:00–02:00, 22:00–23:00 May 19 22:00–24:00 May 20 22:00–24:00 May 22 21:00–22:00 May 26 01:00–02:00 May 27 00:00–01:00, 23:00–24:00 May 28 00:00–01:00, 22:00–23:00 May 29 19:00–20:00 May 31 00:00–01:00
June
Jun 1 00:00–01:00, 14:00–15:00 Jun 2 21:00–23:00 Jun 3 22:00–24:00 Jun 4 23:00–24:00 Jun 5 00:00–01:00, 21:00–24:00 Jun 7 23:00–24:00 Jun 8 23:00–24:00 Jun 9 23:00–24:00 Jun 10 00:00–01:00 Jun 11 22:00–24:00 Jun 12 23:00–24:00 Jun 13 00:00–01:00, 16:00–17:00 Jun 14 23:00–24:00 Jun 16 21:00–23:00 Jun 19 23:00–24:00 Jun 21 13:00–14:00, 23:00–24:00 Jun 22 00:00–01:00, 11:00–13:00, 23:00–24:00 Jun 23 22:00–24:00 Jun 24 23:00–24:00 Jun 25 13:00–14:00, 23:00–24:00 Jun 26 22:00–24:00 Jun 27 19:00–20:00 Jun 28 02:00–03:00 Jun 29 00:00–03:00, 15:00–16:00, 22:00–23:00 Jun 30 21:00–23:00
July
Jul 1 23:00–24:00 Jul 2 00:00–01:00 Jul 3 23:00–24:00 Jul 4 00:00–01:00 Jul 5 00:00–01:00 Jul 6 01:00–02:00 Jul 7 23:00–24:00 Jul 8 22:00–23:00 Jul 9 23:00–24:00 Jul 10 00:00–01:00 Jul 12 00:00–02:00, 23:00–24:00 Jul 13 00:00–01:00, 19:00–20:00 Jul 14 00:00–01:00, 22:00–23:00 Jul 15 22:00–24:00 Jul 18 00:00–01:00 Jul 20 19:00–21:00, 23:00–24:00 Jul 21 23:00–24:00 Jul 22 00:00–01:00 Jul 23 00:00–01:00
August
Aug 5 21:00–22:00 Aug 6 02:00–04:00 Aug 10 21:00–23:00 Aug 12 23:00–24:00 Aug 13 00:00–01:00, 23:00–24:00 Aug 15 03:00–05:00, 23:00–24:00 Aug 16 00:00–01:00 Aug 17 01:00–03:00, 07:00–08:00, 18:00–19:00 Aug 19 00:00–02:00 Aug 20 23:00–24:00 Aug 21 00:00–01:00 Aug 22 00:00–03:00 Aug 24 22:00–24:00 Aug 26 00:00–01:00 Aug 27 00:00–02:00 Aug 28 00:00–02:00 Aug 29 23:00–24:00 Aug 30 00:00–02:00, 23:00–24:00 Aug 31 23:00–24:00
September
Sep 1 23:00–24:00 Sep 2 00:00–01:00, 23:00–24:00 Sep 3 00:00–01:00 Sep 4 02:00–03:00 Sep 5 00:00–01:00, 23:00–24:00 Sep 6 00:00–02:00, 21:00–22:00 Sep 7 22:00–23:00 Sep 9 22:00–24:00 Sep 10 17:00–18:00, 23:00–24:00 Sep 11 00:00–01:00, 23:00–24:00 Sep 14 02:00–03:00, 21:00–22:00 Sep 15 23:00–24:00 Sep 16 00:00–01:00, 23:00–24:00 Sep 17 23:00–24:00 Sep 19 23:00–24:00 Sep 21 19:00–20:00 Sep 22 23:00–24:00 Sep 23 23:00–24:00 Sep 24 23:00–24:00 Sep 25 22:00–24:00 Sep 27 01:00–02:00, 21:00–22:00 Sep 28 22:00–23:00 Sep 29 22:00–23:00 Sep 30 23:00–24:00
October
Oct 1 23:00–24:00 Oct 2 23:00–24:00 Oct 3 23:00–24:00 Oct 4 00:00–01:00, 23:00–24:00 Oct 5 22:00–23:00 Oct 10 00:00–02:00 Oct 11 00:00–01:00, 22:00–24:00 Oct 12 23:00–24:00 Oct 13 00:00–01:00, 22:00–23:00 Oct 14 21:00–22:00 Oct 16 00:00–01:00 Oct 19 23:00–24:00 Oct 20 22:00–23:00 Oct 22 00:00–01:00, 23:00–24:00 Oct 23 00:00–01:00 Oct 26 22:00–24:00 Oct 28 00:00–01:00 Oct 29 00:00–02:00, 23:00–24:00
November
Nov 4 00:00–01:00 Nov 5 00:00–01:00, 23:00–24:00 Nov 6 00:00–01:00 Nov 7 00:00–01:00 Nov 8 00:00–01:00 Nov 11 01:00–02:00 Nov 12 00:00–02:00 Nov 13 00:00–01:00 Nov 14 23:00–24:00 Nov 19 01:00–02:00 Nov 20 00:00–01:00, 22:00–24:00 Nov 22 23:00–24:00 Nov 24 00:00–01:00 Nov 25 00:00–01:00 Nov 26 23:00–24:00 Nov 27 00:00–01:00 Nov 28 01:00–02:00 Nov 30 20:00–23:00
December
Dec 3 22:00–23:00 Dec 4 23:00–24:00 Dec 8 00:00–01:00, 22:00–23:00 Dec 10 00:00–01:00, 23:00–24:00 Dec 12 02:00–03:00 Dec 13 00:00–01:00, 23:00–24:00 Dec 14 00:00–01:00, 23:00–24:00 Dec 17 00:00–01:00 Dec 18 00:00–01:00 Dec 22 00:00–01:00 Dec 23 00:00–01:00 Dec 24 03:00–05:00 Dec 31 02:00–04:00