I have been monitoring the temperature of a mirror surface placed outside at night. The temperature is measured at 10s intervals and so, as you can imagine, a plot of the data for one period is quite noisy. I have therefore decided to "smooth" the data by plotting a moving average over a ten-minute time period. This is where I need some help. I need to plot some error bars. I've tried plotting the standard deviation of the data in the ten-minute time periods used for the moving averages, but it doesn't look right. Because the temperature has, in some cases, remained constant for up to two hours, I have ended up with almost no error bars except for little ovals of errors where the temperature changes significantly. Would it be better practice to simply plot the uncertainty in the measurement caused by the apparatus instead? The temperature probe I am using has an uncertainty of +/-0.5 degrees. Or is there a way of combining the uncertainty of the measurement with the standard deviation? I just don't think it's correct to have large proportions of my graphs with "zero" errors, especially as I know that there is an uncertainty from the temperature probe. Any advice, or suggestions for potentially useful books on the subject would be much appreciated.