I find using the various APIs (Xively, Thingspeak, etc.) to be too difficult for me. Try as I might, I spend hours getting things to work, and I often have to give up. I’d love, for instance, to get graphs of things like temperature and humidity, but have had limited success. I tried IFTTT to collect data from temp and humidity and send to a google spreadsheet for graphing, but IFTTT only allows threshold events (like if the temp rises above x, then log it on a spreadsheet) for temp and humidity.
For me, some of the promise of IOT is gathering data you can use–energy use, for example–not just turning things on and off. And gathering data includes representing it visually for those of us who find combing through logs tedious.
It appears that Safari handles date strings differently. I have made some changes to the way dates are handled for IOS devices. I have no way of testing, but you can reply here if it works or does not.
I also added a time zone selector on the edit account page. If you have a time zone selected the times on the chart will match your local time, if not they will continue to be displayed in UTC. @mattjfrank tested it on an iPad and confirmed that it works.