Generally it's more difficult to get RTK Fix in raining weather. Here we demonstrate how Alpha performs under heavily raining weather condition using the UPM-Lite Kit with the high precision antenna placed on roof of vehicle at 1.6Km baseline distance. It's seen that with 15 usable satellites, it starts getting RTK Fix solution in about a minute but switching between Float and Fix states. Takes about 3.5 minutes to stabilize to stable RTK Fix condition. On sunny days, it would converge to stable RTK Fix state much more quickly.
Some receivers claim spectacular under 60sec* RTK convergence time, but with obscured footnote * stating "Depends on atmospheric conditions, baseline length, GNSS antenna, multipath conditions, satellite visibility, and geometry". Below table shows an example how Alpha compares with such major brand single-frequency RTK receiver, as good or slightly better!
When number of usable satellites can be 19 or more, Alpha can have RTK initialization time under 30sec as seen is this blog.