hours later, it would appear as follows: Year 1: Day 4 at sunset (Tuesday) Year 2: Day 5 at midnight (Thursday) Year 3: Day 6 at sunrise (Friday) Year 4: Day 7 at noon (Saturday) Year 5: Day 2 at sunset (Sunday) Year 6: Day 3 at midnight (Tuesday) Every four years sees a jump of an additional day because the four six-hour periods sum to a full day. This is somewhat similar to a solar leap year occurring every 4 years to account for the four quarter days that accrued at a rate of a quarter day per year. Although the proper time for the blessing would be at sundown on Tuesday April 7, the Sun is no longer visible at sundown; the blessing is therefore delayed until the following morning. The 28-year cycle is based on a solar year of 365.25 days, which is only nearly precise. The Hebrew calendar itself uses a solar year of 365.2468222 days, but utilizes the less precise approximation of 365.25 for Birkat Hachama so that the blessing might occur with some frequency. See also Hebrew calendar: Accuracy. How the date is calculated This table represents a week with all the 24 hours marked and labeled by the "planet", actually a celestial light in direct translation, which corresponds to them according to the ancient geocentric model of "planet" order. It is based on Rashi's commentary to Eruvin 56a. We create this table by noting that in the Bible the stars were created on Wednesday at twilight so we place Saturn (the first "star") at hour 1 (or 6:00 p.m.). Then we follow with all the six other "planets" (Jupiter, Mars, Sun, Venus, Mercury, and Moon) and repeat the order until all the hours of the week have a "star" assigned to them. We assume the world was created in the Hebrew month of Nissan, not Tishrei. So hour 1 (sunset) on Wednesday on this chart represents the beginning of Tekufat Nissan (Spring) in the first year of creation, the Hebrew year 1. For the purpose of Birkat Hachama, the calculation of Samuel of Nehardea for the length of a tropical year is used not the more accurate calculation of Adda bar Ahavah. Therefore, a year is assumed to be 52 weeks and one day and six hours (365.25 days). This means that a year after creation Tekufat Nissan will occur one day and