What factors influence which Pokemon appears as the daily guaranteed Pokemon encounter?

Question

Because of COVID-19, a guaranteed Pokemon encounter occurs daily. This Pokemon has a white circle surrounding it.

I'm wondering what factors, if any, increase or decrease the likelihood of certain Pokemon appearing?

Based on my observations, but not on proven facts or large group results:

• Weather boosted Pokemon are more likely to appear
• Pokemon that are more common in the wild are more likely to be the daily Pokemon, for example Numel
• Pokemon that don't appear in nests can be the daily Pokemon. For example, one of my guaranteed encounters was a Gible.
• It does not appear to be influenced by nearby nests
• The Pokemon is unlikely to be evolved and is never a legendary

Answer 1

The Silph Road recently published an article on their research into the factors influencing daily spawns. The research found that almost all available wild spawns including regional, event, and evolved forms are candidates. The daily spawn is registered upon the first time you open the app after midnight, local time. At that time, the relative frequency of encountering a species is influenced by these few factors:

• weather
• time of day
• location

The weather factor corresponds to the hourly weather in game, increasing the chance of a weather boosted species. The time of day relates to the day or night cycle, where certain types are more likely to appear; for example, dark types are more likely at night. Location has always been a primary factor in spawns, with the common example of spawn points near water features having an increased chance of water types. One consequence is that even rare species may appear common in certain areas.

Beyond answering the question, the article mentions that some species do not appear as daily spawns, but the cautionary note is whether they are extremely rare and not encountered yet.