A few weeks ago I placed one of my temp loggers in my attic just for fun. I charted the data and noticed some really odd temperature fluctuations.

See charts

As you can see, some days there are weird spikes up to 85 or more degrees. Keep in mind this is VA and it's barely Spring yet, with temps in the 40-60 range. Some days the attic temperature remains almost constant.

I can't figure it out. I thought maybe it was windy days that would suck the heat out but looking at the weather history, that does not appear to be the case.

We have a programmable thermostat, which lowers the temp at night but that doesn't explain the wild temp swings during the day. The temperature Inside the house is quite comfy and stable. The house is barely 7 years old and has blown insulation in the attic.

Any ideas?