The Tempest 23 is a recreational keelboat built by the O'Day Corp. in the United States from 1964 to 1968, with 390 boats built.
The fiberglass hull has a raised counter, angled transom; and a skeg-mounted rudder controlled by a tiller. It has a hull speed of .
It is a masthead sloop. The sail plan consists of a 115.00 sq. ft. mainsail, 113.10 sq. ft. jib and 339.00 sq. ft. spinnaker. It can be sailed with a Tri-radial headsail.
It has two berths in the "V"-berth. The galley is on the port side just forward of the companionway ladder. The galley is equipped with a two-burner stove. The head is opposite the galley on the starboard side. Cabin headroom is .
In a 2010 review Steve Henkel wrote, "the O'Day Tempest 23 (not to be confused with the similarly named O'Day International Tempest, an open-cockpit racing machine) is a classic, attractive, and wholesome design for basic overnight cruising. Best features: Relatively long overhangs and low freeboard give this boat a sleek, graceful look typical of Philip Rhodes' designs. Flotation under cockpit sole and V-berth is a good safety feature. Her broader beam and deeper draft compared to the Cape Cod Marlin ... help to make her more weatherly and stiff, despite the MarlinâÂÂs heavier but closer-to-the-surface ballast. On the other hand, the two Pearson comp[etitors]s [the Pearson 23 Sloop and Pearson 23 Cat] surpass the Tempest in weatherliness and stiffness for the same reasons. Worst features: Her keel is iron rather than lead, requiring diligent maintenance to prevent deterioration from rust. Lack of a good place to put a portable cooler keeps her from qualifying as more than a basic overnighter, and overall space below is less than all her comp[etitor]s, partly due to her reduced headroom. She is known to sail slower than her PHRF rating,"