Hi, thanks for using Hebcal. Sorry to hear about the difficulty with the API.

It turns out the issue you're seeing is actually due to caching, and not due to the &o=on parameter. When you specify cfg=json, the results are cached for 24 hours. We set a 24-hour expiry to reduce load on our servers and to speed up the results for clients. However, depending on where you are on the planet, today is either June 1 or May 31.

Note the age header below:

Michaels-MBP:~ mradwin$ curl --compressed -v 'https://www.hebcal.com/hebcal?v=1&cfg=json&year=now&month=now&d=on&o=on' | jq .title
> GET /hebcal?v=1&cfg=json&year=now&month=now&d=on&o=on HTTP/2
> Host: www.hebcal.com
> User-Agent: curl/7.54.0
> Accept: */*
> Accept-Encoding: deflate, gzip
> 
< HTTP/2 200 
< server: nginx/1.18.0 (Ubuntu)
< date: Tue, 01 Jun 2021 15:44:10 GMT
< content-type: application/json; charset=utf-8
< content-length: 835
< vary: Accept-Encoding
< etag: W/"d9-CQGoPjGBqbw/ZdAoggDClB0DGFA"
< last-modified: Sun, 30 May 2021 22:46:51 GMT
< cache-control: max-age=86400
< content-encoding: gzip
< x-response-time: 3.875ms
< x-varnish: 37561102 34898242
< age: 61543
< via: 1.1 varnish (Varnish/6.2)
< access-control-allow-origin: *
< accept-ranges: bytes
< 
"Hebcal Diaspora May 2021"
Michaels-MBP:~ mradwin$ curl --compressed -v 'https://www.hebcal.com/hebcal?v=1&cfg=json&year=now&month=now&d=on&o=on' | jq .title

In approximately 7 hours the cache will expire and you'll get the results for June 1.

If you specify the exact month and year (for example https://www.hebcal.com/hebcal?v=1&cfg=json&year=2021&month=6&d=on&o=on ) you will see that although &o=on is specified, you'll correctly get the June 2021 events.

In the future, I think we could safely reduce the cache from 24 hours to 4 hours when year=now and/or month=now to improve the coherency of the results without a significant impact on the user experience.

Hi, thanks for using Hebcal and thanks for your feedback.

We recently redesigned the holidays year-on-a-page to be more mobile friendly and to better clarify that holidays start the evening before (except for minor fasts which begin at dawn).

https://www.hebcal.com/holidays/2022

We hope you enjoy the new design!

In short: yes!

Feel free to make printed calendars, email newsletters, refrigerator magnets, and other content using events from Hebcal.com.

Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution 3.0 License.

Among other things, this license gives you permission to remix, transform, and build upon the material for any purpose, even commercially. You must give appropriate credit to Hebcal.com, but beyond that you need not send us money or even explicitly ask us for permission.

https://www.hebcal.com/home/44/reproduce-hebcal-content-creative-commons

Thanks so much! That was helpful to have the URL, and we understand what the problem is. We have now fixed the problem. Please refresh the page and it should look correct now.

Could you send a screenshot, paste the URL of the page, or upload the PDF file that you think is problematic? We are not aware of any issues causing dates to be off.

Thanks. Fixed!

Hi, thanks for using Hebcal.

For Israel this is the URL we publish which shows only one day for Shavuot

https://www.hebcal.com/holidays/shavuot?i=on

Which says: Shavuot (Festival of Weeks) for Hebrew Year 5782 begins in 🇮🇱 at sundown on Saturday, 4 June 2022 and ends at nightfall on Sunday, 5 June 2022.

And for Diaspora (chutz l'aretz) we publish this page

https://www.hebcal.com/holidays/shavuot

Which says: Shavuot (Festival of Weeks) for Hebrew Year 5782 begins in the Diaspora at sundown on Saturday, 4 June 2022 and ends at nightfall on Monday, 6 June 2022.

I hope this extra location information helps.

Hi, thanks for using Hebcal. Sorry to hear about your difficulty with deleting multiple events.

When hebcal exports to CSV format, it puts the text "Hebcal" or “Jewish Holidays” in the Location or Description field. That is there to make it easy to remove entries from your calendar if you got the wrong settings. For example, if you were using candle-lighting times but entered the wrong zip code, you could follow these instructions to remove all of the incorrect entries:

1. Open your Calendar and on the View menu point to Current Viewand click Events
2. Click the Location column heading to sort the list of holidays by Location (you should see “Jewish Holidays” in the location field for the holidays that you imported from CSV)
3. Click to select the first holiday you want to delete
4. Hold down SHIFT and click the last holiday you want to delete
5. Press DELETE to remove all the selected holidays from your Calendar

Here are similar instructions for Outlook desktop on Mac

https://www.hebcal.com/home/1113/mac-outlook-2011-remove-hebcal-jewish-calendar

This is available in the JavaScript @hebcal/core API. You can call Event.getFlags() and then bitwise-AND with both flags.CHUL_ONLY and flags.CHAG.

In August 2020 we updated our solar calculation engine, which enabled this feature.

Havdalah can now be calculated according to tzeit hakochavim, the point when 3 small stars are observable in the night time sky with the naked eye. The new default Havdalah option is calculated when the sun is 8.5° below the horizon. This option is an excellent default for most places on the planet. We still offer the option to use a fixed number of minutes past sundown (e.g. 42 min for three medium-sized stars, 50 min for three small stars, 72 min for Rabbeinu Tam) which works well for Israel, most of the USA and Europe.

https://www.hebcal.com/home/1548/hebcal-2020-year-end-updates