Tuesday, January 29, 2008

Sunrise/Sunset...

It is clear that I am destined to obsess over every little detail of this impending wedding, including details that I cannot control. Such as: the weather and the sunset.

Now, this being the 21st century and astronomy and physics having progressed very far in the last 500 years, I can say with much certainty that the sun will set at precisely 6:45 pm. This fits in nicely with cocktail hour; shortly after the sun sets, the guests proceed from the veranda with their mint juleps to the main barn for dinner...



The weather, however, is less predictable, particularly with global warming relentless attacking us the way it does these days. I have done a careful analysis of the weather in Durham on October 11 over the past 62 years. Graph 1 shows a histogram of the average temperature (F) binned by 5 degrees. Fortunately it falls to an approximate Gaussian, meaning the sample size is large enough to make some guesses. The average temperature is 60 degrees with a standard deviation of 7, pretty much a nice fall day. But that is the mean of averages, which doesn't really tell us anything. We really want to know what are the chances of it being too hot or too cold.


Graph 2 is a histogram of the high temperature (F) with the same binning. Not as nice looking but we can still get some useful information. The average high for that day is 74 +/- 8. And since the wedding is most likely starting at 5:00, we should expect us to be just coming off such a high. The lows similarly fit more or less to a Gaussian, giving an average overnight low of 50 +/- 9.


Of course, global warming is still a concern. Fortunately the daily highs, lows and averages remain consistent if I only average them over the last 30 years. Plotting the temperatures in a scatter plot reveals no discernible pattern (Graph 3). This is good. It means that I am unable to predict the weather with high school level statistics.

So, we've covered sunset and temperature. All that's left is rain. That we will have to save for another day.

1 comment:

Michelle said...

I know this is waaay after you wrote this, but I am glad to see that I am not the only one who did the weather analysis! But seeing as how we are getting married in Nov. in TX, it will either be 56 or 95 degrees, you never know! :)