The company completely sold out of the device within six hours of it becoming available for pre-order on April 10th. Many models currently have an estimated ship date of 4-6 weeks, others won't ship until June or July.
Analysts believe that Apple could sell between 2.3 to 4 million units in the quarter ending June. Typically, Apple would have released pre-order numbers today; however, it did not, possibility due to the supply issue.
Piper Jaffray analyst Gene Munster said, "Overall we view the trends over the weekend as an indication of solid demand paired with very limited supply, with supply being the most significant limiting factor."
Munster expects Apple to ramp up production between mid-May and June.
A recent Slice Intelligence study estimated that Apple took 1 million pre-orders in the United States on the first day of sales. In comparison, sales of all other Android-power smartwatches totaled 720,000 in all of 2014.
Notably, analysts at Pacific Crest say industry checks indicate that Apple has ordered enough components to make over 20 million units this year.