Jessica Lundquist, assistant professor of civil and environmental engineering at the University of Washington, uses a dog-ball launcher to ensure that the balls land far into the trees.
This inexpensive approach to science has already been recognised by the American Geophysical Union, which gave her the cryosphere young investigators award last year.
Ms Lundquist said: "I have a lot of fun deploying my sensors because I love being in the mountains. They also sense conditions in these remote environments that we can't know about any other way."
The tennis ball sensors, which she originally designed for use with frozen foods in transit, cost around $30 (£18) each and are able to measure the temperature every hour for up to 11 months.
A scientific weather station will usually cost around $10,000.
This week, Wired News reported that a Wiimote has been hacked by Rolf Hut of Delft University of Technology, so that it acts as a wind sensor.
