Strange behavior of historic items

Hey there,
im logging some temperatures with influxdb and visualize the data thru grafana. Im using this rules and persist on every change.

rule "Temperaturen Wochenextrema draußen"
when 
	Item Wettermast_Temperature changed  or
	Time cron "0 1 * * * ? *"
then 
	Wettermast_Temperature_Min_Week.postUpdate((Wettermast_Temperature.minimumSince(now.minusWeeks(1)).state))
	Wettermast_Temperature_Max_Week.postUpdate((Wettermast_Temperature.maximumSince(now.minusWeeks(1)).state))
end

But as you can see, between 04:00 and 06:00 the temperature “Wochenminimum” increases, whats sensless.
Surprisingly after a few hours, it goes back to the right level.

Can anyone explain this to me or knows a workaround?

Greetings,
Fabian

Are you certain that your device or source of the data is not reporting these higher values? That is the first place I would look. You can look at the values or Wettermast_Temperature in events.log between those times and see if the values it is being set to are “correct” or if they are elevated. If they are elevated, it isn’t a problem with InfluxDB or Grafan, but what ever is sending the temp values.

The visualization is correct, so there might be a problem with the minimumSince method.

2017-02-25 01:23:03.274 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.40 to 1.30
2017-02-25 01:25:41.622 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.30 to 1.20
2017-02-25 01:30:15.163 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.20 to 1.10
2017-02-25 01:35:58.825 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.10 to 1.20
2017-02-25 02:03:05.695 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.20 to 1.10
2017-02-25 02:15:59.427 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.10 to 1.20
2017-02-25 02:26:14.587 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.20 to 1.10
2017-02-25 02:34:36.518 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.10 to 1.00
2017-02-25 02:38:59.109 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.00 to 1.10
2017-02-25 02:52:06.858 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.10 to 1.20
2017-02-25 03:04:34.067 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.20 to 1.10
2017-02-25 03:09:34.547 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.10 to 1.20
2017-02-25 03:42:08.504 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.20 to 1.10
2017-02-25 03:44:22.062 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.10 to 1.00
2017-02-25 03:50:12.274 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.00 to 0.90
2017-02-25 03:55:05.272 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 0.90 to 0.80
2017-02-25 04:02:44.947 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 0.80 to 0.70
2017-02-25 04:38:19.684 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 0.70 to 0.80
2017-02-25 04:48:04.117 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 0.80 to 0.90
2017-02-25 04:52:33.969 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 0.90 to 1.00
2017-02-25 04:58:13.579 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.00 to 1.10
2017-02-25 05:36:44.079 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.10 to 1.20
2017-02-25 05:48:55.913 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.20 to 1.30
2017-02-25 05:51:55.579 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.30 to 1.40
2017-02-25 12:19:36.171 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from NULL to 1.40
2017-02-25 14:04:12.037 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.4 to 1.3
2017-02-25 14:13:12.007 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.3 to 1.1
2017-02-25 15:35:13.099 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.1 to 1.0
2017-02-25 17:02:15.419 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 1.0 to 0.9
2017-02-25 17:13:15.710 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 0.9 to 0.8
2017-02-25 17:18:15.822 [ItemStateChangedEvent     ] - Wettermast_Temperature_Min_Week changed from 0.8 to 0.7