Zmanim today: what alos, netz, sof zman krias shema, shkia and tzeis actually mean

Every frum calendar, shul board and siddur app shows a column of times called zmanim. Most people know they need to say Shema before "sof zman" and daven Mincha before shkia, but fewer could explain where those times come from or why two calendars sometimes disagree by several minutes. This guide explains each zman in plain language.

A note before we start: this is an overview, not a psak. Where opinions differ — and they often do — follow your community's practice and ask your Rav.

Why zmanim change every day

Halachic times are tied to the sun, not the clock. Sunrise and sunset move every day through the year and differ from town to town, so every zman moves too. Zmanim for Lakewood are not the same as for Monsey, and both shift a minute or two from one day to the next. That is why a fixed schedule printed once a year is never quite enough, and why you always want zmanim for today, for your location.

The halachic hour (sha'ah zmanis)

Many zmanim are measured in sha'os zmaniyos — "proportional hours". The day is divided into twelve equal parts, so in the summer a halachic hour is longer than sixty minutes and in the winter it is shorter. There are two main ways of defining "the day" for this purpose:

• The Gra and the Baal HaTanya: from sunrise to sunset.
• The Magen Avraham: from alos hashachar (dawn) to tzeis hakochavim (nightfall).

Because the Magen Avraham's day starts earlier, his times for the morning zmanim come out earlier. That is why many calendars list two times for sof zman krias shema.

The zmanim, in order through the day

Alos hashachar (dawn). The first light in the east. It is commonly calculated as 72 minutes before sunrise, or by the sun's angle below the horizon; calendars differ in which method they use.

Misheyakir. The earliest time for tallis and tefillin, when there is enough light to recognise someone at a short distance. Calendars calculate it by the sun's angle, and opinions differ.

Netz hachama (sunrise). Ideal for the Shemoneh Esrei of Shacharis, especially for those who daven vasikin.

Sof zman krias shema. The end of the third halachic hour. Shema should be said before this time. Calendars show the Magen Avraham time and the Gra time.

Sof zman tefillah. The end of the fourth halachic hour — the time by which Shacharis should be davened.

Chatzos (midday). Halachic midday, halfway between sunrise and sunset (not 12:00).

Mincha gedolah. Half a halachic hour after chatzos — the earliest time for Mincha.

Mincha ketanah. Nine and a half halachic hours into the day.

Plag hamincha. One and a quarter halachic hours before the end of the day. Relevant, for example, to davening Maariv early or lighting Shabbos candles early in the summer, according to many opinions.

Shkia (sunset). Mincha should be davened before shkia. Many calendars also show the time for candle lighting, which in many communities is 18 minutes before sunset on Erev Shabbos and Yom Tov (in Yerushalayim it is customarily earlier).

Tzeis hakochavim (nightfall). When three stars appear. This is the time for Maariv's Krias Shema and for the end of Shabbos and Yom Tov. Calendars calculate it by the sun's angle or a fixed number of minutes after sunset, and many communities wait longer on Motzei Shabbos.

Why two zmanim apps disagree

If your phone and the shul's calendar differ, it is usually one of these:

• Different opinions (Gra vs Magen Avraham, different calculations of alos or tzeis).
• Different location — your exact spot versus the town centre.
• Elevation — some calendars adjust sunrise and sunset for height.

None of these is "wrong"; they are different methods. Use the one your community follows.

Where to check today's zmanim

Kall Siddur shows a zmanim strip for your location at the top of the siddur: sunrise, sof zman krias shema and tefillah, chatzos, shkia and tzeis. It works offline once opened, so the zmanim are there even without a signal.

Kall Local uses today's zmanim to work out the next Shacharis, Mincha and Maariv at shuls near you — handy when you are racing shkia.

And Kall Reminders knows the zmanim too: a reminder that would ring on Shabbos or Yom Tov waits until after havdalah. Its Shabbos times use candle lighting at 18 minutes before sunset and havdalah at tzeis hakochavim (8.5°); you set your own location in Settings.

In short

Zmanim follow the sun, change every day, and differ by town and by opinion. Know which ones your community follows, check them for today, and when in doubt, ask your Rav. Open Kall Siddur to see today's zmanim where you are.