Weather was being built into Yandex Maps: a precipitation layer, a time slider, and a "X minutes in the rain" figure on each route. The question was whether people notice it while planning a trip, and whether they read it correctly.
I ran a usability study with 5 participants. The task said nothing about weather: you have just left a dentist in an unfamiliar part of town, your dog is waiting at home, taxis are unavailable, work out how to get back.
Whatever weather information people saw first became the information they used, and they did not look for the rest. Not one participant opened the precipitation layer, even though all of them wanted a rain map and understood what the button was for. The time slider was dragged rather than tapped, which is not how it works. And the "minutes in the rain" figure read ambiguously: people could not tell whether it covered the whole route or only the part on foot.
I recommended reducing three entry points into the rain map to one and moving it into the route details, where attention already is; making the slider actually draggable; and using the same order of information for walking and transit routes, since people expect to find the same thing in the same place.
Course project, Yandex Praktikum UX research programme.