Might you not speed it up with fewer samples? Every minute seems excessive (maybe you needed that for developing/debugging).

That choked my dual core 2.5g.

There isn't really any developing/debugging as such. I've been playing with temperature sensors with my RPis and I wanted to put one outdoors and I decided it would be nice to look at the data in a graph. Every minutes is definitely overkill but it's very quick when I access the data locally, I think it would be slow even if the data was held on the hosting server, especially when it gets to weeks and months worth of data.

At that rate, 24 hours' worth is only 60k or so – 1440 data points per series, which is not a huge amount, and like I said earlier, even my phone can handle that with no noticeable slowing.

No drop shadow! :O

A MySQL question.

Due to there being missing parts on the chart for the shorter readings because of the missing entries I've changed how the data is pulled from the database by calculating the current time minus the length of time required then only fetching the rows that are greater than this calculated time. It works nicely and gives a proper day, week length etc.

My question is should I be indexing my "unixtime" column to make it easier on the DB? 

New code is...

$currtime = time();

$newlimit = $currtime - $limit;

SELECT * FROM outside WHERE unixtime > $newlimit ORDER BY id DESC

I suck at using the new editor.

Yes, an index would be useful there.

The editor sucks at being used, more like.

Is it a cache issue that is causing no grey box to appear when I want to add code in the new editor? Only "code:" appears I end up having to go in to the HTML and put things between the pre tags but there's divs all over the place.

Could be a cache issue, it's showing here on both "Teh Forum" and "Yellow" themes.

Another slightly irrelevant cool thing: http://ankane.github.io/chartkick/

Ant- What a cool/interesting thing to do.
Is your questioned answered?  I imagine so by now, but don't have time to read.