I have seen many instances where a very small nick in the wire coating would short enough to keep the station from running, but not enough to blow the fuse, when soil moisture was high such as after rain. Its a jiffy to locate and repair with a pulser. Also intermittant failures like this can occur due to other loose connections such as at the terminal strip, splices, or solenoid connections. As far as solenoid failure, seems unlikely twice in a row, without come direct cause such as lightning. You can test the solenoid simply by reading the resistance through the coil right at the clock, using a volt meter (that measures resistance) read the resistance (Ohms) down the COM wire and the particular station wire; a good solenoid will read in the mid twenties (25-27 Ohms).

Do the troubleshooting and it will be simple to fix the problem.

Here is a link that might be useful: Troubleshooting