Pontia occidentalis
In 3 days ~20% in a week ~30%
Pontia occidentalis, the western white, is a butterfly in the family Pieridae. It is found in Western North America. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Glacier National Park | 🇺🇸 United States | |
| 2 | Banff National Park | 🇨🇦 Canada | |
| 3 | Jasper National Park | 🇨🇦 Canada | |
| 4 | Elk Island National Park | 🇨🇦 Canada | |
| 5 | Riding Mountain National Park | 🇨🇦 Canada | |
| 6 | Grand Teton National Park | 🇺🇸 United States | |
| 7 | Yosemite National Park | 🇺🇸 United States | |
| 8 | Rocky Mountain National Park | 🇺🇸 United States | |
| 9 | Yellowstone National Park | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Western White sighting in Yosemite National Park on a given day, based on 10 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 134th most-seen of the 227 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
June to August
In those months about 10% of wildlife watchers report a Western White in Yosemite National Park on a given day, against under 5% in September to May, the lowest months. Those are among Yosemite National Park's driest months, with about 25 mm of rain a month against 220 mm in January.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Western White sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
7th of 9
Of the 9 parks where we can rate Western White sightings, Yosemite National Park ranks 7th at about 10%. The best odds are in Glacier National Park (United States, about 20%), Banff National Park (Canada, about 10%) and Jasper National Park (Canada, about 10%).
GBIF citizen-science records
It is estimated from how often the Western White is recorded against all the insects logged in Yosemite National Park (10 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
