The likelihood of rainy weather when you visit Majorca really depends on the time of year. If you visit between September and April, then you are more likely to experience rain, the heaviest usually during November and December. Visit Majorca outside of these months and you're more likely to find dry weather and sunshine.
Average rainfall in Majorca in centimetres
To avoid the rainy season altogether, the best of the summer weather in Majorca spans May through to the end of August, and often continues through September.
Of course there can still be rain showers during the summer, as anywhere, but they tend to happen much less frequently and are often short showers that can provide refreshing relief from the hot sun.
If you do happen to witness a thunderstorm during your stay, be prepared for memorable thunder and lightning, stunning if you can get a good viewing point!