You can display:
Dates and hours of lowest and highest temperature
Lowest, highest and mean temperature
Mean ± Standard deviation

Start to display the values from :

Mean temperature : ?
Lowest temperature : ?
Highest temperature : ?
Date, hour and temperature of the selection: ?


Is there something not clear? Try this :
?
?
1990
1995
2000
2005
2010
2012
7 days
30 days
Half a year
1 year
3 years
6 years
0°C
10°C
20°C
30°C
Here you can able/disable some features that are displayed on the graph.
Here you can chose the first date that has to be displayed.
This is the temperature graph.
If you click and drag you can zoom the graph although you cannot display less than one week.
This slider show where the starting and ending date shown are with respect to the whole dataset.
With this slider you can chose how many values are displayed.
These are some descriptive numbers that are calculated using only the displayed values. It is also show the selected date, hour and temperature.
With this you can go to the home page.
Glossary

Mean: is the average value of the dataset considered.
Standard deviation: it is a number that measure the scatter of the dataset. Highter standard deviation means that the values are far from the mean. The interval Mean ± Standard deviation is the interval where about the 68% of the values lies in the graph.
Least square line: a line which has the property of assessing the data so that the actual values differ the least possible from those of the line.