  Simple climate models have been around for more than a century but have
recently come back into fashion: they are useful for explaining global warming
and the habitability of extrasolar planets. The Climate App
(https://www.climateapp.ca) is an interactive web-based application that
describes the radiative transfer governing planetary climate. The App is
currently available in French and English and is suitable for teaching
high-school through college students, or public outreach. The beginner version
can be used to explore the greenhouse effect and planetary albedo, sufficient
for explaining anthropogenic climate change, the Faint Young Sun Paradox, the
habitability of TRAPPIST planets and other simple scenarios. There is also an
advanced option with more atmospheric layers and incorporating the absorption
and scattering of shortwave radiation for students and educators wishing a
deeper dive into atmospheric radiative transfer. A number of pedagogical
activities are being beta tested and rolled out.
