San Diego is 9 hours behind Madrid
Best overlap: 5:00 PM to 6:00 PM in Madrid is 8:00 AM to 9:00 AM in San Diego.
Your window to reach both cities is 5:00 PM to 6:00 PM in Madrid, which converts to 8:00 AM to 9:00 AM in San Diego. You've got roughly 1 hour — enough for a focused daily check-in if you hold it at 5:00 PM in Madrid (8:00 AM in San Diego).