This is a fairly common problem on XTs. It is usually the junctions at each end of the HT lead that are the cause of the issue in wet weather.

Nine times out of ten there is no need for a new coil, HT lead or plug cap. Just dry the whole lot out fully (hairdryer is good if you want it done quickly) and cover the connection between lead and coil, and lead and cap with a smear of silicone grease. This will keep the moisture at bay.

__________________