Header image  
   
   DRAFT 1
 
 
 
 

 
 
Abstract
We reviewed the average monthly low and high temperatures for North American cities representing various climate regions. We plotted 50 years of data for each city for each month. For each set of data we determined the linear best fit. We found evidence that the climate is getting warmer. We also noticed that the night time low temperatures are rising faster than daytime high temperatures.
Our Hypothesis

We predicted that we would see the night time lows increasing but the daytime highs would not show an increase. We also predicted that winter would show more increase than spring and summer. The hypotheses were based on the experience of some of the adults we interviewed.

History of these pages
These pages were the product of an 8th grade math-science expedition designed to show that student could be involved in real science research. After the school took down the web-site we acquired these pages and removed thereference to the school. All other elements of these pages are from the original product.
Our Methods

First we downloaded the information from the National Climate Data Center. Then we put the information into spreadsheet form. Using the information we plotted graphs. We plotted each month separately looking at the monthly average highs and monthly average lows. We did a best fit linear approximation and measured the rate of change.

For example, in the following graph for June high and low temperatures in Barrow Alaska the linear best fit for the available data is shown with black lines. High temperatures are showing an average increase of 0.9'F per decade, low temperatures are showing an increase of 0.5'F per decade.

 
 
   

 

Data Analysis (monthly)
This graph shows all of our data.

The typical increase in high temperatures is 0.2'F per decade. The typical rise in low temperatures is 0.6'F. As we predicted, low temperatures are rising faster than high temperatures.

[more detail]

As we predicted more warming is occurring in the winter. January, February, and March the average increase in temperatures is 0.7'F per decade. In September and october the lows are rising the least (average (0.2'F per decade). June, July, and August the highs are rising the least (average 0'F per decade.)

Average Annual Change
Below we map the annual average change in low temperatures. Each state is color coded based on the city with analyzed in that state. Our measurements showed low temperatures increasing in most states, with only Lambertville NJ showing a cooling trend in its low temperatures. (see both low and high maps)
 
Summation
  Lows Highs
min
-1.7
-1.1
25%
0.1
-0.1
ave
0.4
0.3
75%
0.6
0.5
max
3.0
3.5

The average lows are rising just slightly faster than the highs. The fastest warming is occurring in Alaska. In the midwest high temperatures appear to be dropping while lows rise. In two eastern states lows appear to be dropping while the highs rise. Temperatures are rising fastest January through March. On the average temperatures are remaining level July through October. Overall we are seeing more rising temperatures than fall.

Conclusions
We hypothesized that low temperatures are rising and highs are not. This is true is some areas, but overall both lows and highs are rising. Lows are rising slightly faster than highs. We hypothesized that winter temperatures were rising the fastest. We saw this in our data. Winter temperatures are rising about 0'5'F faster than summer temperatures.