Pontia occidentalis
In 3 days ~10% 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 |
Rare
Under 5% of wildlife watchers report a Western White sighting in Yellowstone National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 127th most-seen of the 160 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
August and September
In those months about 10% of wildlife watchers report a Western White in Yellowstone National Park on a given day, against under 5% in October to July, the lowest months.
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.
9th of 9
Of the 9 parks where we can rate Western White sightings, Yellowstone National Park ranks 9th at under 5%. 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%).
Same family: Pieridae
The closest relatives of the Western White that you can see in Yellowstone National Park (family Pieridae, Whites, Yellows, and Sulphurs) are Clouded Sulphur (about 10%), Julia Orangetip (about 10%) and Margined White (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Western White is recorded against all the insects logged in Yellowstone National Park (7 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.
