Yep, in 2017[0]. Suppose it depends on what you mean by works.. can we cause precipitation (yes - [0]) or change precipitation (yes - [1] regularly done to decrease hail magnitude).

[0]: https://www.cbc.ca/radio/quirks/feb-29-coronavirus-containme... [1]: https://letstalkscience.ca/educational-resources/stem-in-con...