Supergirl season 5 is only 20 episodes. A video breaking down most probable reasons for this reduction.

APOLOGIES IF YOU CAME THE OTHER DAY AND DID NOT SEE A VIDEO - I had to remove it temporarily, as Youtube had deemed it not ad friendly, due to me talking about COVID-19 in it. I had to remove that whole piece, now its OK'ed.... so I can put it back up.
Since I had to remove that part, I will add a breakdown of what I said in here. So, watch the video, then read on below, or vice-a-versa.

If you have been paying attention to the Supergirl fandom for a while, you might have heard rumblings for a few months about the possibility that Supergirl would only be 20 episodes in season 5.

Well, till recently, they were just rumours. But now, confirmation has come in the way of their production schedule being reduced by almost a month. While the decision for this change was surely done a while ago, it is now just public knowledge, as these things usually are not made public till late in a production (usually its for a time extension. Not too common it is a reduction).

Will the new Superman & Lois have any impact on it? Did Melissa Benoist get a new role on a different project? Has the threat of COVID-19 caused things to wrap early (had to remove that part.... so its right here in the next paragraph)?

Since the new pandemic COVID-19 (more commonly known as the "coronavirus" which is misleading a bit, since theres many strains of Coronavirus, but COVID-19 is this specific strain) has become such a notable thing. Especially here in Vancouver where 9 cases of it have been reported in the last month, and right across the border from us in Washington State they have had 9 deaths from it. People are wondering if the panic about this virus is to blame for the quick end. No. Plain and simply, it is not. This was planned long before this was even a thing anyone had heard of. On top of that, the likelyhood ANY current crews would stop for it is low. The cause for concern would have to skyrocket, and quick, for that to happen as most projects have 4 to 5 weeks left of filming. Now COULD it have an impact come next seasons filming? Maybe. If things get notably worse between here and late June, there absolutely could be enough concern to delay filming till the pandemic has become greatly minimized. But that is an issue they will not think about till closer to the time of filming for that. As for this season, barring it hitting a specific crew hard (not talking 1 or 2 cases, but enough that work cant be done), it is very unlikely they would halt production this close to the end of season.

In the video below, I break down the most likely reason, and debunk some of the most discussed rumours that have popped up about it.