As always, the Pokemon GO spotlight hour features a single Pokemon for an hour that will spawn all around the map at constant rates. In this case, it's Mankey, and any players who need a Primape should take the chance to catch as many as possible. The event runs from 6:00 pm to 7:00 pm local time, and there will be double xp for evolving any Pokemon in that hour.
One of the major draws for the spotlight hour in Pokemon GO, aside from finishing an evolution or xp bonuses, is catching a shiny Pokemon. Not every featured spotlight Pokemon will have a shiny form, but luckily Mankey does. Every Kanto region entry in Pokemon GO now has a shiny form after the Kanto event went live, and that includes Mankey.
How to increase the chances of a shiny Mankey in the Pokemon GO spotlight
Catching a shiny Mankey won't be a guarantee, just like any other shiny in Pokemon GO. It's always a matter of luck no unless it's part of a research event. But that doesn't mean players can't increase the odds just enough to get at least one.
The best option is always using an incense which will attract Mankey to the player for the entire hour. Lures, which are incense used at a Pokestop, can be used as well along with the incense. It will create a constant stream on Mankey spawns in that hour.
Walking around populated areas with at least a few Pokestops is the last way to try to maximize the chance of a shiny Mankey. It's important to note that players don't need to catch Mankey to see if it's shiny. Simply start an encounter and if it's not shiny, back out if the candy is unnecessary.