You can't go wrong with a nice pair of dress pants and a shirt and tie. Jeans, sandals or shorts, unless such attire is mentioned on the invitation, are never acceptable.
According to weddingchannel.com:
Think "special clothes". Depending on the season, your attire is likely to be lighter colored and a bit more casual that you might wear for an evening wedding. Men should still plan to wear a suit or nice sports coat and slacks, and a tie.
If you are invited to an informal or semi-formal or even a formal daytime wedding, that is, morning, early afternoon or tea time wedding you may wear a dress shirt and slacks and bring a sports jacket.
Take cues from the other guests. If most do not wear sport jackets then it is your option not to wear yours. If the majority does wear jackets, then you are prepared. Either way, don't forget the tie.
If you are invited to a formal daytime an informal or semi-formal evening wedding, wear a suit and tie.