If you can't find the "rubber booties", you can use silicone sealing tape to weatherproof your connectors. It is readily available at local home improvement stores. Check this link:
Silicone Fusing Tape You just wrap the connector with the stretchy tape. In two or three days the tape fuses to itself and forms a weather tight seal. It can be easily removed by scoring it with a razor knife. I have used it for years on outdoor ham radio antenna connections and never had a failure. There is another product out there that is called Coax-Seal but I do not recommend it. It certainly keeps out the weather but is sticky and needs to be covered with vinyl tape and it is not easily removed. If you do find a source for the booties please share it here on the list.