Most often in March, 21 days.
Highest follower count seen that year: 4,761.
February
Feb 28 01:00–04:00
March
Mar 2 01:00–05:00 Mar 3 00:00–01:00, 04:00–05:00, 14:00–19:00 Mar 6 01:00–02:00, 04:00–05:00 Mar 7 00:00–01:00, 13:00–14:00 Mar 8 00:00–01:00, 05:00–07:00 Mar 10 00:00–04:00, 15:00–20:00 Mar 11 00:00–01:00, 06:00–08:00, 15:00–19:00 Mar 12 02:00–13:00 Mar 15 11:00–12:00 Mar 16 01:00–03:00, 07:00–10:00 Mar 18 01:00–03:00, 09:00–10:00, 12:00–13:00 Mar 19 00:00–01:00, 06:00–11:00, 15:00–21:00 Mar 20 02:00–06:00, 11:00–14:00 Mar 22 04:00–10:00, 12:00–17:00 Mar 23 15:00–19:00 Mar 24 08:00–13:00 Mar 26 03:00–08:00, 15:00–19:00 Mar 27 16:00–19:00 Mar 28 02:00–04:00, 08:00–11:00 Mar 30 03:00–07:00, 12:00–13:00, 16:00–18:00 Mar 31 16:00–20:00
April
Apr 1 00:00–03:00, 06:00–09:00, 12:00–14:00 Apr 3 02:00–05:00, 09:00–16:00, 23:00–24:00 Apr 4 00:00–01:00, 03:00–04:00, 16:00–18:00 Apr 5 02:00–04:00 Apr 7 04:00–06:00, 13:00–15:00, 23:00–24:00 Apr 8 22:00–24:00 Apr 9 00:00–01:00, 09:00–13:00 Apr 11 05:00–06:00 Apr 12 23:00–24:00 Apr 13 00:00–01:00, 05:00–07:00 Apr 15 02:00–08:00, 12:00–17:00 Apr 17 03:00–04:00 Apr 19 02:00–03:00 Apr 21 07:00–09:00, 11:00–13:00 Apr 23 10:00–12:00 Apr 25 03:00–04:00, 06:00–08:00, 10:00–12:00 Apr 27 03:00–04:00, 12:00–13:00
May
May 6 16:00–19:00 May 7 02:00–03:00 May 9 01:00–03:00 May 14 04:00–05:00 May 25 01:00–04:00 May 26 17:00–20:00 May 29 01:00–04:00 May 30 06:00–07:00 May 31 01:00–06:00
June
Jun 2 08:00–12:00 Jun 4 00:00–02:00 Jun 7 05:00–06:00 Jun 8 02:00–10:00 Jun 10 09:00–15:00, 23:00–24:00 Jun 11 00:00–04:00, 06:00–08:00 Jun 12 15:00–17:00 Jun 14 02:00–03:00 Jun 15 02:00–03:00, 14:00–20:00 Jun 16 09:00–10:00 Jun 19 15:00–21:00 Jun 26 02:00–03:00
July
Jul 16 07:00–08:00 Jul 17 14:00–15:00 Jul 22 01:00–08:00 Jul 24 01:00–02:00 Jul 25 07:00–13:00, 15:00–16:00 Jul 28 02:00–04:00 Jul 30 02:00–04:00
August
Aug 1 01:00–03:00, 07:00–08:00 Aug 3 01:00–03:00 Aug 5 09:00–11:00, 14:00–15:00 Aug 6 16:00–19:00 Aug 7 02:00–03:00, 12:00–13:00 Aug 9 01:00–07:00, 13:00–14:00, 23:00–24:00 Aug 10 01:00–02:00, 07:00–11:00 Aug 11 02:00–08:00 Aug 13 15:00–18:00 Aug 17 01:00–03:00 Aug 19 00:00–08:00, 11:00–12:00 Aug 22 05:00–12:00 Aug 23 02:00–05:00, 10:00–13:00 Aug 25 02:00–12:00 Aug 26 03:00–07:00, 10:00–16:00 Aug 27 00:00–01:00, 05:00–12:00 Aug 29 03:00–08:00, 11:00–14:00, 23:00–24:00 Aug 30 00:00–02:00, 05:00–07:00 Aug 31 06:00–10:00
September
Sep 2 01:00–06:00, 11:00–14:00 Sep 3 00:00–04:00, 10:00–12:00 Sep 4 01:00–05:00 Sep 6 03:00–04:00 Sep 10 02:00–04:00 Sep 11 06:00–10:00, 12:00–13:00 Sep 12 02:00–03:00 Sep 14 06:00–08:00 Sep 15 05:00–09:00 Sep 16 00:00–10:00 Sep 18 01:00–03:00, 11:00–12:00 Sep 22 01:00–03:00, 07:00–09:00
October
Oct 1 02:00–04:00, 06:00–07:00 Oct 2 10:00–11:00, 13:00–14:00 Oct 5 01:00–02:00 Oct 7 00:00–03:00, 06:00–08:00, 10:00–11:00 Oct 9 11:00–13:00 Oct 10 01:00–02:00, 13:00–16:00 Oct 12 05:00–06:00 Oct 13 07:00–08:00 Oct 14 12:00–14:00 Oct 15 02:00–06:00 Oct 16 01:00–04:00 Oct 17 07:00–10:00, 12:00–13:00 Oct 18 04:00–05:00, 07:00–10:00 Oct 19 09:00–11:00 Oct 20 11:00–18:00 Oct 21 03:00–04:00 Oct 26 06:00–11:00 Oct 28 02:00–03:00, 05:00–06:00, 10:00–12:00 Oct 29 03:00–05:00, 08:00–13:00 Oct 30 01:00–05:00, 07:00–11:00
November
Nov 1 01:00–06:00, 09:00–11:00 Nov 2 02:00–05:00 Nov 3 01:00–04:00 Nov 5 08:00–09:00 Nov 7 02:00–04:00, 09:00–11:00 Nov 9 08:00–10:00 Nov 10 02:00–05:00, 08:00–09:00 Nov 11 00:00–02:00, 12:00–13:00 Nov 13 01:00–04:00, 08:00–12:00 Nov 15 01:00–04:00 Nov 17 01:00–04:00 Nov 18 01:00–04:00, 14:00–19:00 Nov 23 01:00–02:00, 06:00–10:00 Nov 25 01:00–04:00 Nov 26 03:00–06:00, 09:00–12:00, 23:00–24:00 Nov 27 00:00–03:00, 13:00–14:00 Nov 29 03:00–04:00, 07:00–09:00, 13:00–17:00 Nov 30 00:00–02:00, 04:00–09:00, 16:00–18:00
December
Dec 1 04:00–07:00 Dec 3 03:00–06:00, 10:00–12:00, 14:00–15:00 Dec 4 00:00–04:00, 08:00–11:00 Dec 11 01:00–04:00 Dec 12 03:00–04:00 Dec 13 02:00–06:00, 09:00–10:00 Dec 15 02:00–04:00, 10:00–12:00 Dec 16 00:00–07:00 Dec 17 10:00–11:00 Dec 19 05:00–06:00, 09:00–11:00 Dec 21 05:00–07:00 Dec 23 03:00–04:00, 21:00–22:00 Dec 24 07:00–08:00 Dec 25 05:00–06:00, 10:00–11:00