That’s when the first of a series of road closures are introduced, lasting until the end of the United Nations climate change conference in three weeks’ time.
The Clydeside Expressway, a key route into the city centre from the west, will be shut to traffic along with several surrounding streets, including the Clyde Arc, better known as the “Squinty bridge” over the Clyde.
They are being closed as part of security preparations for the global event at the Scottish Event Campus (SEC) complex.
But perhaps introducing the restriction a week early will turn out to have been a smart move, enabling traffic to settle into a new equilibrium on diversionary routes.
In my experience, the more warnings there are of traffic gridlock or "chaos”, the less likely it’ll happen as drivers find other ways around or choose not to travel.
Even so, roads such as the Clyde Tunnel, Great Western Road and Dumbarton Road/Argyle Street are likely to be busier – even if the threatened ScotRail strikes are averted and streets are not blocked by protesters.
The Insulate Britain campaign group, which has repeatedly blockaded the M25, has told me it has no current plans to come to Glasgow, but said it might change its mind.
However, if you think the likely extra emissions from congestion caused by a climate change summit is ironic, spare a thought for those trying to continue cycling.
Rather than being allowed to continue riding along Glasgow’s bike “motorway” along the Clyde, outside the 3m-high COP26 security fencing, cyclists will be forced to make a detour that includes onto roads with traffic.
Parts of the diversionary route will be segregated from cars, but some of these appear to be entirely inadequate, with at least one stretch on Argyle Street so narrow as likely to risk cyclists and pedestrians colliding.
The opportunity seems to have been missed to provide a gold standard alternative route that underlines the key importance of encouraging more cycling in the face of the climate emergency that COP26 is seeking to address.