# Aggregate on timstamp part
**URL:** https://discuss.elastic.co/t/aggregate-on-timstamp-part/63073
**Category:** Kibana
**Created:** [October 14, 2016, 6:56pm UTC](https://discuss.elastic.co/t/aggregate-on-timstamp-part/63073 "2016-10-14T18:56:29Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Bruno\_Lavoie](https://discuss.elastic.co/u/Bruno_Lavoie)
#### Post date: [October 14, 2016, 6:56pm UTC](https://discuss.elastic.co/t/aggregate-on-timstamp-part/63073/1 "2016-10-14T18:56:29Z")
Hello,
I would like to make graphs on a specific part of @timestamp field.
Say, we want an average per hour over a certain period of time.
Is it possible to do that easily in Kibana?
Do we need a script field? If yes, how?
Is it necessary to preprocess this date field splitting in logstash to make it possible?
Thanks
Bruno Lavoie
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [October 15, 2016, 9:01pm UTC](https://discuss.elastic.co/t/aggregate-on-timstamp-part/63073/2 "2016-10-15T21:01:37Z")
Just set the time buckets to hourly in the agg. But that wont work over (eg) years of data as the granularity is too small.
---
### Author:  [@Bruno\_Lavoie](https://discuss.elastic.co/u/Bruno_Lavoie)
#### Post date: [October 17, 2016, 2:41pm UTC](https://discuss.elastic.co/t/aggregate-on-timstamp-part/63073/3 "2016-10-17T14:41:27Z")
Oh, maybe I wasnt clear enough...
I want a bucket/aggregation by time part (day of week, hour).
So, if I select last year with an agregation on hour part of @timestamp, I will have 24 buckets (one for each hour).
The only way that I've found is to add a scripted field in kibana:
`doc['@timestamp'].getHourOfDay()`
But I have questions regarding performance of this and where is it executed: in kibana or ES?
And, big drawback of this solution is that it's not timezone aware: extracted values are in UTC. Any way to convert it back to the client TZ?
Thansk
Bruno Lavoie
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [October 17, 2016, 10:40pm UTC](https://discuss.elastic.co/t/aggregate-on-timstamp-part/63073/4 "2016-10-17T22:40:35Z")
So you want a bucket of 0000-0100 for all days in the year?
---
### Author:  [@Bruno\_Lavoie](https://discuss.elastic.co/u/Bruno_Lavoie)
#### Post date: [October 18, 2016, 12:22pm UTC](https://discuss.elastic.co/t/aggregate-on-timstamp-part/63073/5 "2016-10-18T12:22:13Z")
> [@warkolm](#):
>
> -0100 for all days in the year?
hum the buckets would be:
- 00h00
- 01h00
- ...
- 23h00
this can be for the year or last month or whatever the user select in time range in Kibana.
Thanks
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 1:36pm UTC](https://discuss.elastic.co/t/aggregate-on-timstamp-part/63073/6 "2017-07-06T13:36:21Z")