Since it’s usually blastin’ hot here even well into November I’m not accustomed to having to dress warmly. However, since I’ll be visiting the frozen northlands I thought I’d see what the weather is usually like at the end of October. Fortunately for me we have the United States Historical Climatology Network where you can get daily temperature and precipitation data for lots of places including Central Park in convenient comma delimited format. Yays!
The first thing we learn is that looking back more than 100 years it has only snowed within a day of October 31st one time and that was in 1925 and it was very little. So good for me, it doesn’t snow that early. Since it doesn’t really get cold enough to snow how about rain? Really cold rain sucks way more than snow. Looking at those same three days it has rained 79 times out of 316 recorded days, which is conveniently exactly 1/4 of the time. However the average amount of rain is 1/10th of an inch which is barely rain at all. It has rained a half inch or more 27 times and an inch or more 10 times. Rain appears unlikely enough that a jacket that is reasonably water resistant would be sufficient and if it happens to be one of those unlikely days where it actually rains I can buy an umbrella. I would call the precipitation data a gamma distribution but JMP doesn’t like the fact that mostly the measurements are 0″ though I thought that was the point of the whole thing. I guess I need to dig out my probability text book.
Speaking of jackets let’s talk temperature. It gets cold in New York. They actually have seasons other than summer up there. The normality test fails for the temperature data but that’s not hugely important though I am going to treat it as though it was later. The average average daily temperature for October 30th, 31st and November 1st is 53.1°F with std. dev. being 7.1°F. The average maximum temperature is 60°F, std. dev. 7.9°F and the average minimum temperature is 45.7°F, std. dev. 7.1°F. That’s something we can work with. The minimum and maximum temperatures I’m not that worried about, I’m going to be in the city during the day, not at 3AM and I’m going to be inside mostly except for a few hours walking and on the train platform. Only 5% of the time will a data point fall outside of two standard deviations from the mean. That says to me that for the time I’m going to be there I have a reasonable expectation of the temperature being 53.1°F ± 2 * 7.1°F or between 67°F and 39°F. That’s chilly but certainly not parka weather and I don’t think I’ll bring a heavy coat. I’ve been told that I should layer my clothing and that I will need a “fleece layer” and a “wind layer”. I think this means that I’m going shopping. Also, yay!