Dutch online travel agent Tjingo has created a simple visual tool to quickly see global rain patterns for trip planning purposes.
The company notes in the opening paragraph above the map that customers are always asking about best times to travel to particular places:

Especially for regions with rainy seasons, of countries with major climate fluctuations, this obviously is an important question. This is why Tjingo created an overview with the most extreme rainfall, based on precipitation data of the past 30 years. Move the slider from left to right to see the heavy rainfall move over the earth.
The data is presented in several slides, one looking at global rain patterns and then several breakouts that focus on individual regions.
A slider sits at the bottom of each image, and allows travelers to visualize average rain at each week in the year. So for those preferring to avoid rain, this allows selection of the ideal time to travel. On the flip side, for afternoons spent on a porch reading in the rain, the tool identifies the best times to experience rainy season in any of these regions.
The data is sourced from the National Weather Service Climate Prediction Center, which has been tracking daily precipitation for 30 years. This allows the interactive infographic to reveal the historical averages of the past 30 years in an easy to consume, week-by-week fashion.
This data visualization is another example of how startups and travel brands can repurpose widely-available data into interesting interfaces that improve customer service by answering frequently asked questions.
Another idea in this realm was delivered in a Tnooz Thack in Singapore, where a group created a tool to visualize where the sun would be during a specific flight. Called SunFlight, it offers knowledge of sun location to inform seat selection. There is a depth of additional information available for travel startups creating consumer-facing products.
The Rain Patterns tool is available here.