Inspired by hint from Spring One.
Using the same code is not working with Spring Webflux- MDC context is not passed into Reactor part:
2021-11-11 10:04:35.099 INFO 49909 --- [ main] c.matejuh.webfluxmdc.WeatherController : request_id=fd8f7621-0a5c-44a3-882e-8b8e1185d3d2 action=getWeather
2021-11-11 10:04:35.856 INFO 49909 --- [ctor-http-nio-2] webClient : request_id= method=GET uri=https://wttr.in?AT status=200 OK
2021-11-11 10:04:35.881 INFO 49909 --- [ main] com.matejuh.webfluxmdc.LoggingFilter : request_id=fd8f7621-0a5c-44a3-882e-8b8e1185d3d2 method=GET uri=/weather status=200