Colias philodice
In 3 days ~10% in a week ~30%
Colias philodice, the common sulphur or clouded sulphur, is a North American butterfly in the family Pieridae, subfamily Coliadinae. This species is a typical member of the genus. Both genders typically have pale yellow wings above with no traces of orange, unlike its close cousin the orange sulphur which may also be yellowish. Males have clean borders, while females have yellow dots within this region. Females sometimes exhibit a white form known as alba.
The underside of the male's wings is yellow while the female's is yellow or greenish white, and both have a doubled hindwing spot trimmed in brownish red. The hindwings show a series of four small red spots along the outer third portion, a trait that distinguishes the other North American species such as Colias interior, with exception of the orange sulphur which also shows them. Its wingspan is 32 to 54 mm.
Form alba This species has white form alba which can be very common in some populations, while rare in others. It can be confused with other white forms of Colias particularly that of Colias eurytheme. It can often be distinguished by the border pattern of both wings, though some individuals are impossible to... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Kluane National Park | 🇨🇦 Canada | |
| 2 | Elk Island National Park | 🇨🇦 Canada | |
| 3 | Point Pelee National Park | 🇨🇦 Canada | |
| 4 | Banff National Park | 🇨🇦 Canada | |
| 5 | Yellowstone National Park | 🇺🇸 United States | |
| 6 | Grand Teton National Park | 🇺🇸 United States | |
| 7 | Acadia National Park | 🇺🇸 United States | |
| 8 | Glacier National Park | 🇺🇸 United States | |
| 9 | Shenandoah National Park | 🇺🇸 United States | |
| 10 | Jasper National Park | 🇨🇦 Canada | |
| 11 | Riding Mountain National Park | 🇨🇦 Canada | |
| 12 | Rocky Mountain National Park | 🇺🇸 United States | |
| 13 | Great Smoky Mountains National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Toronto | 🇨🇦 Canada | |
| 2 | Calgary | 🇨🇦 Canada | |
| 3 | Edmonton | 🇨🇦 Canada | |
| 4 | Montreal | 🇨🇦 Canada | |
| 5 | Boston | 🇺🇸 United States | |
| 6 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 7 | Chicago | 🇺🇸 United States | |
| 8 | Denver | 🇺🇸 United States | |
| 9 | Detroit | 🇺🇸 United States | |
| 10 | New York City | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Clouded Sulphur sighting in Rocky Mountain National Park on a given day, based on 10 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 125th most-seen of the 191 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.
July to September
In those months about 10% of wildlife watchers report a Clouded Sulphur in Rocky Mountain National Park on a given day, against under 5% in October to June, the lowest months.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Clouded Sulphur sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
12th of 13
Of the 13 parks where we can rate Clouded Sulphur sightings, Rocky Mountain National Park ranks 12th at about 10%. The best odds are in Kluane National Park (Canada, about 30%), Elk Island National Park (Canada, about 20%) and Point Pelee National Park (Canada, about 10%).
Same genus: Colias
The closest relatives of the Clouded Sulphur that you can see in Rocky Mountain National Park (genus Colias, Clouded Yellows) are Mead's Sulphur (about 10%), Queen Alexandra’s Sulphur (about 10%) and Colias scudderi (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Clouded Sulphur is recorded against all the insects logged in Rocky Mountain 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.
