Updated and republished for macOS 10.15.6 Supplemental Update 1; skip it unless you really really care about all the macOS releases. Originally published on November 14th, 2005.

Below the break is a table showing all major releases of macOS (previously Mac OS X) from the public beta through the latest public version, which is macOS 10.15.6 SU1, as of August 12th, 2020—the 137th release in total.

Note: Click the ⓘ symbol to read Apple's release notes for a given update.

The following was culled from Apple's support downloads page, and as such, some of the dates may be off just a bit. If you know for certain that something is incorrect, please let me know and I'll get it fixed. (Scroll to see all entries.)

Year Date Days Version Size Comments 2020 Aug 12 28 10.15.6 SU1 3.22GB GB ⓘ Jul 15 44 10.15.6 3.35 GB ⓘ Jun 1 6 10.15.5 SU1 1.59 GB ⓘ May 26 48 10.15.5 3.37 GB ⓘ Apr 8 15 10.15.4 SU1 1.38 GB ⓘ Mar 24 56 10.15.4 3.0 GB ⓘ Jan 28 49 10.15.3 3.0 GB ⓘ 2019 Dec 10 42 10.15.2 3.0 GB ⓘ Oct 29 14 10.15.1 4.5 GB ⓘ Oct 15 8 10.15 SU1 985 MB No info page Oct 7 11 10.15 4.9 GB ⓘ Catalina - You need more permission! Sep 26 31 10.14.6 SU3 1.32 GB ⓘ Aug 26 25 10.14.6 SU2 1.25 GB ⓘ Aug 1 10 10.14.6 SU1 949 MB ⓘ Jul 22 70 10.14.6 2.7 GB ⓘ May 13 49 10.14.5 2.5 GB ⓘ Mar 25 62 10.14.4 2.8 GB ⓘ Jan 22 48 10.14.3 2.0 GB ⓘ 2018 Dec 5 28 10.14.2 2.5 GB ⓘ Nov 7 8 10.14.1 SU1 1.3 GB ⓘ For 2018 MacBook Air Oct 30 36 10.14.1 3.3 GB ⓘ Sep 24 27 10.14 5.2 GB ⓘ Mojave - The 'you need permission' release Aug 28 38 10.13.6 SU2 1.32 GB ⓘ For 2018 Touch Bar MBP…again Jul 24 15 10.13.6 SU1 1.31 GB ⓘ For 2018 Touch Bar MBP Jul 9 38 10.13.6 1.32 GB ⓘ AirPlay 2 Jun 1 64 10.13.5 2.12 GB ⓘ Messages in iCloud Mar 29 37 10.13.4 2.36 GB ⓘ Sortable Safari bookmarks!! Feb 20 28 10.13.3 SU 40.4 MB ⓘ Indian character/Messages crash fix Jan 23 33 10.13.3 1.97 GB ⓘ Jan 8 33 10.13.2 SU 633.6 MB ⓘ Spectre and Meltdown fixes 2017 Dec 6 36 10.13.2 2.08 GB ⓘ Oct 31 26 10.13.1 1.47 GB ⓘ Oct 5 10 10.13 SU 915 MB ⓘ Addresses two security issues Sep 25 68 10.13 4.8 GB ⓘ High Sierra - Higher in the mountains? Jul 19 65 10.12.6 1.98 GB ⓘ May 15 49 10.12.5 1.57 GB ⓘ Mar 27 63 10.12.4 1.56 GB ⓘ Night Shift Jan 23 41 10.12.3 1.05 GB ⓘ 2016 Dec 13 50 10.12.2 1.94 GB ⓘ Oct 24 34 10.12.1 1.36 GB ⓘ Sep 20 64 10.12 4.77 GB ⓘ Sierra - Still in the mountains. Jul 18 63 10.11.6 759 MB ⓘ May 16 57 10.11.5 759 MB ⓘ Mar 20 61 10.11.4 1.58 GB ⓘ Jan 19 41 10.11.3 662 MB ⓘ 2015 Dec 9 49 10.11.2 1.4 GB ⓘ Oct 21 21 10.11.1 1.19 GB ⓘ Sep 30 48 10.11 6.08 GB ⓘ El Capitan - Go climb something! Aug 13 44 10.10.5 1.02 GB ⓘ Jun 30 75 10.10.4 1.09 GB ⓘ Apr 16 8 10.10.3 SU 1.8 MB ⓘ Supplemental Update Apr 8 71 10.10.3 1.52 GB ⓘ Includes Photos app Jan 27 71 10.10.2 544 MB ⓘ 2014 Nov 17 32 10.10.1 311 MB ⓘ Oct 16 29 10.10 5.2 GB ⓘ Yosemite - No surfers here. Sep 17 79 10.9.5 139 MB ⓘ Jun 30 46 10.9.4 283 MB ⓘ May 15 79 10.9.3 461 MB ⓘ Feb 25 71 10.9.2 460 MB ⓘ 2013 Dec 16 55 10.9.1 243.4 MB ⓘ Oct 22 19 10.9 5.3 GB ⓘ Mavericks - All out of big cats! Oct 3 21 10.8.5 SU 19.6 MB ⓘ Supplemental Update Sep 12 100 10.8.5 273.7 MB ⓘ Jun 4 82 10.8.4 152.0 MB ⓘ Mar 14 161 10.8.3 249.0 MB ⓘ 2012 Oct 4 15 10.8.2 SU 26.7 MB ⓘ Supplemental Update Sep 19 27 10.8.2 665.5 MB ⓘ Aug 23 29 10.8.1 24.2 MB ⓘ Jul 25 77 10.8 4.1 GB ⓘ Mountain Lion - App Store only Oct 4 15 10.7.5 SU 2.0 MB ⓘ Supplemental Update Sep 19 133 10.7.5 1.1 GB ⓘ Released w/ 10.8.2 May 9 98 10.7.4 692.7 MB ⓘ Feb 1 112 10.7.3 1.3 GB ⓘ Only combo updater available 2011 Oct 12 56 10.7.2 768.8 MB ⓘ Now iCloud enabled Aug 17 29 10.7.1 79.3 MB ⓘ Jul 19 26 10.7 4.1 GB ⓘ Lion - App Store only (USB stick later) Jun 23 94 10.6.8 453.6 MB ⓘ App Store readied for Lion Mar 21 74 10.6.7 475 MB ⓘ Jan 6 57 10.6.6 143.6 MB ⓘ Can you say "App Store?" 2010 Nov 10 148 10.6.5 644.5 MB ⓘ Jun 15 78 10.6.4 607.2 MB ⓘ Mar 29 140 10.6.3 719.2 MB ⓘ 2009 Nov 9 60 10.6.2 473 MB ⓘ Sep 10 13 10.6.1 71.5 MB ⓘ Aug 28 23 10.6 2.31 GB ⓘ Snow Leopard - First Intel-only release Aug 5 85 10.5.8 274 MB ⓘ May 12 148 10.5.7 442 MB ⓘ 2008 Dec 15 91 10.5.6 372 MB ⓘ Sep 15 77 10.5.5 316 MB ⓘ Jun 30 33 10.5.4 88 MB ⓘ May 28 107 10.5.3 420 MB ⓘ Feb 11 88 10.5.2 343 MB ⓘ Combo updater only 2007 Nov 15 20 10.5.1 110 MB ⓘ Oct 26 128 10.5 2.15 GB ⓘ Leopard - First universal binary release Nov 14 147 10.4.11 128 MB ⓘ This '10' goes to '11' Jun 20 99 10.4.10 72 MB ⓘ Mar 13 165 10.4.9 160 MB ⓘ 2006 Sep 29 94 10.4.8 206 MB ⓘ Jun 27 85 10.4.7 133 MB ⓘ Apr 3 48 10.4.6 163 MB ⓘ Feb 14 35 10.4.5 16 MB ⓘ Jan 10 71 10.4.4 55 MB ⓘ First Intel-capable release 2005 Oct 31 111 10.4.3 97 MB ⓘ Jul 12 57 10.4.2 44 MB ⓘ May 16 17 10.4.1 37 MB ⓘ Apr 29 14 10.4 1.78 GB ⓘ Tiger Apr 15 65 10.3.9 51.3 MB ⓘ Feb 9 56 10.3.8 26.6 MB ⓘ 2004 Dec 15 40 10.3.7 97 MB ⓘ Combo updater only Nov 5 88 10.3.6 34 MB ⓘ Aug 9 75 10.3.5 ??? ⓘ May 26 72 10.3.4 79 MB ⓘ Combo updater only Mar 15 89 10.3.3 70 MB ⓘ Combo updater only 2003 Dec 17 37 10.3.2 36.9 MB ⓘ Nov 10 17 10.3.1 1.5 MB ⓘ Oct 24 21 10.3 1.54 GB ⓘ Panther Oct 3 57 10.2.8 40 MB ⓘ Aug 7? 93 10.2.7 ??? For first-gen G5s only May 6 26 10.2.6 26 MB ⓘ Apr 10 56 10.2.5 81.9 MB ⓘ Feb 13 56 10.2.4 76 MB ⓘ 2002 Dec 19 38 10.2.3 51 MB ⓘ Nov 11 54 10.2.2 24.4 MB ⓘ Sep 18 26 10.2.1 16.3 MB ⓘ Update not available? Aug 23 79 10.2 1.03 GB ⓘ Jaguar Jun 5 47 10.1.5 45.1 MB ⓘ Combo updater only Apr 19 57 10.1.4 1.7 MB ⓘ Feb 21 62 10.1.3 16 MB ⓘ 2001 Dec 21 37 10.1.2 29.2 MB ⓘ Nov 14 50 10.1.1 13.8 MB ⓘ Sep 25 95 10.1 989 MB ⓘ Puma Jun 22 44 10.0.4 12 MB ⓘ May 9 1 10.0.3 15 MB ⓘ May 8? 22 10.0.2 15 MB Released but replaced (see comments) Apr 16 23 10.0.1 4 MB ⓘ Mar 24 192 10.0 659 MB ⓘ Cheetah 2000 Sep 13 -- 10.0β 676 MB ⓘ Public Beta

Note: The Days column reflects the number of days between releases.

Some entries may appear out of chronological order (i.e. 10.5 is shown on Oct 26, but above Nov 14 for 10.4.11). This is to keep the version numbers in the proper order, even when an older OS received an update after a major new release came out. This has happened a few times over the years.

Some random notes, updated from the original post:

Starting with the Public Beta and up through macOS 10.15.6 SU1, there have been 137 macOS releases, both major and minor. This figure includes every macOS release. There have been two updates—10.0.2, which as far as I can tell, was never released, and 10.2.7, which I believe was the update with the one-day lifespan—that are somewhat odd, but they have been publicly discussed, so I've counted them. If I'm wrong about either of these, please correct me.

macOS releases, both major and minor. This figure includes macOS release. There have been two updates—10.0.2, which as far as I can tell, was never released, and 10.2.7, which I believe was the update with the one-day lifespan—that are somewhat odd, but they have been publicly discussed, so I've counted them. If I'm wrong about either of these, please correct me. As of July 15th, 2020 (macOS 10.15.6's release date), it's been 7,273 days since the Public Beta was released. So on average, we've seen some sort of update every 53 days .

since the Public Beta was released. So on average, we've seen . The shortest time period between any two releases (not counting 10.0.2's one-day release-and-replace) is six days, which is how quickly the 10.15.5 Supplemental Update 1 came out after the 10.15.5 release.

The longest time period between any two minor releases is 165 days, which was how long we waited for the 10.4.9 update.

The smallest update was 10.3.1, at only 1.5MB. The largest (non-combo, non-main OS release) update was 10.15.1 at 5.3GB.

The "???" entry for Size on a given release indicates I was unable to find the size. Feel free to contact me if you can help replace any of the "???" entries.

And now, gratuitous graphics…

Releases by version number

Releases by year

A special "thank you!" goes to Mr. Ziebell (for providing some size values on very-old minor updates), and to Benton Quest (for providing size info on all the major releases up through Snow Leopard). See Benton's comment below if you want a nicely detailed history of those early releases.