When Do We Count?
The Omer is counted from the second night of Passover through the night before Shavuot. It is best to count the Omer at nightfall, immediately after the evening prayer. However, one may count at any time throughout the night.
After sunset, one should avoid saying, “Today is the… day” before first reciting the blessing—e.g., in response to someone who asks—for if he does so, he has already fulfilled his obligation. If, however, he only said the number of days without prefacing it with “Today is…,” he has not fulfilled his obligation and may recite the blessing. Nevertheless, it is best to reply with the number of days counted on the previous day.
One Who Forgot to Count
If one forgot to count at night, he should count during the day without a blessing, and may count with a blessing on the subsequent nights. If he forgot to count during the day as well, he must count on the rest of the nights without a blessing. If one is in doubt as to whether he had counted on the previous night, and did not count during the day, he may continue counting with a blessing. Before counting the Omer, one should not begin eating (even a light meal) within half an hour before twilight.
How Do We Count?
The chazzan recites the blessing and counts the Omer, followed by the congregation. The Omer is counted standing. While counting the Omer, bear in mind: the corresponding sefirah of that night; one word from the Psalm May God be gracious; one letter from the verse The nations will rejoice; and one word from We implore You (as indicated in Hebrew).
