Three weeks after July 7th’s Articuno Day came Zapdos Day, the crowning bonus of GO Fest bonus week on July 21st. It brought a new three hour shot to catch the second of the Legendary bird trio, with a shiny surprise for many lucky travelers! As promised, the Silph Research Group headed out en masse to collect data on the probability of encountering a shiny Zapdos.

Now, on the eve of Moltres Day, we’re excited to share the results from this large-scale, controlled study!

Findings

Once our researchers’ race against the clock and mighty thunder bird concluded, 5,700+ Raids had been recorded. To our great surprise the shiny rate for Zapdos clocked in at approximately:

1 in 10

with a 95% confidence interval of 1 in 9.7 to 1 in 11.3.

This shiny rate is exactly double the rate found during Articuno Day and all other Legendary Raids with a shiny possibility to date.

Was this yet another bonus from Professor Willow’s Global Challenge? A boosted rate unique to this event only? Or is this something we can expect for the highly-anticipated Moltres Day tomorrow (September 8th)? We’ll have to wait and see!

Practical Application

This doubled shiny rate has significant implications on the odds that a traveler can expect to find at least one shiny Legendary during an event of this format. Travelers have been offered 5 free Raid Passes for participating in these events, but many opt to complete additional Raids using Premium Raid Passes during the 3-hour window. Let’s look at the probability of receiving at least one shiny under six scenarios – both with a shiny rate of 1 in 20 and 1 in 10:

# of Raids Probability of at least 1 shiny 1 in 20 1 in 10 5 Raids 22.6% 41.0% 10 Raids 40.1% 65.1% 15 Raids 53.7% 79.4% 20 Raids 64.2% 87.8% 25 Raids 72.3% 92.8% 30 Raids 78.5% 95.8%

‘Casual’ Raiding travelers who completed less than 10 Raids saw their chances of a shiny Legendary nearly double – a welcome surprise for those going in to the day with very low expectations. For more hardcore travelers who completed 25+ Raids, the likelihood of not finding a shiny dropped dramatically from ~28% on Articuno Day to ~7% on Zapdos Day, meaning four times fewer hardcore travelers returned home empty handed on Zapdos day.

Moltres Day & Beyond

Whatever the shiny rate may be for Moltres Day, we anticipate exciting times are around the corner! In the meantime, we have the other Yokosuka challenge rewards to enjoy and a number of other shiny species to catch (with Growlithe as the newest arrival). These past months have been a whirlwind of activities and fun, and it’s far from being over yet!

Good luck on your shiny hunt, travelers!

– Scientist Ansku –

P.S. Thanks to Scientists DrThod and Titleist12 for the calculations.