Latitude & Temperature: Teacher Notes
Core Standards: 8.EE.7, S.ID.6-8
Resources:
Mathematics Teacher October 2008
www.worldclimate.com
Review the meaning of “latitude”: it is a geographic coordinate measuring the distance (north or south)
from the equator. Latitude is measured in degrees. The values of latitude range from 0 o (equator) to 90o
(north and south poles). Discuss the expected effect of latitude on average daily temperatures, for
example, the equator is typically very warm. Barrow, Alaska has a latitude of 71.3 o N, and an average daily
temperature in April of -2oF. If students add Barrow, Alaska to the plot, it is not close at all to the
prediction line. But it isn’t a vacation spot, either!
Ask: What other variables might affect average daily temperature? Altitude, weather patterns, soil
type (some soils absorb more heat from the sun), desert vs. forest, etc.
Depending on the level of instruction, students can find a linear equation to fit the data using either
representative points to calculate the slope and find the y-intercept, or linear regression using technology.
̂ = −0.8𝑥 + 85.1
The line of best fit (without Logan and St. George) is 𝑦
The correlation is -0.9, indicating the line is a pretty good fit to the data.
St. George, UT
Logan, UT
City
Recife, Brazil
Caracas, Venezuela
Mexico City, Mexico
Miami, FL
Charleston, SC
Phoenix, AZ
Washington, DC
Kansas City, MO
New York, NY
Chicago, IL
Caribou, MW
Vancouver, Canada
Juneau, AK
Latitude
8.0 N
10.5 N
19.4 N
25.8 N
32.9 N
33.4 N
39.0 N
39.1 N
40.7 N
43.0 N
46.2 N
49.2 N
58.4 N
Average April Temperatures
(in degrees F)
79.0o
70.3o
64.4o
74.5o
64.8o
68.4o
52.9o
55.6o
50.4o
50.5o
37.8o
48.0o
39.6o
Prediction equation obtained by linear regression:
The slope of the line is -0.8, indicating that for every increase in degree latitude, the temperature goes
DOWN by .8 degrees.
The y-intercept is 85.1, indicating that at x=0 (the equator) the average daily temperature in April would
be estimated at 85.1o F.
Logan and St. George are shown on the graph with open circles.
City
Latitude
Logan, UT
41.75
St. George, UT
37.1 N
Average April Temperatures
(in degrees F)
Actual = 45.0 Fo
Predicted = 51.7 Fo
Actual = 58.5 Fo
Predicted = 55.4 Fo
Logan’s average April temperature is probably lower than predicted because of the elevation, situated in a
mountain valley, elevation 4500 ft above sea level. St. George’s average April temperature is probably
higher than predicted because of the semi-desert climate.
Students might be interested in using the www.worldclimate.com website to look up latitude, altitude, and
average daily temperatures for other cities in different months of the year.
Name _______________________
Class Period_____
Latitude & Temperature
Data points were chosen from selected vacation destinations from www.worldclimate.com, The data
shows the average daily temperatures in the month of April. Plot the points on the graph.
City
Latitude
Recife, Brazil
Caracas, Venezuela
Mexico City, Mexico
Miami, FL
Charleston, SC
Phoenix, AZ
Washington, DC
Kansas City, MO
New York, NY
Chicago, IL
Caribou, MW
Vancouver, Canada
Juneau, AK
Equator
8.0 N
10.5 N
19.4 N
25.8 N
32.9 N
33.4 N
39.0 N
39.1 N
40.7 N
43.0 N
46.2 N
49.2 N
58.4 N
Average April Temperatures
(in degrees F)
o
79.0
70.3o
64.4o
74.5o
64.8o
68.4o
52.9o
55.6o
50.4o
50.5o
37.8o
48.0o
39.6o
North Pole
Latitude & Temperature
1. Find the prediction line for the data.
2. What is the slope?
_________
3. What is the y-intercept? _________
Interpret the slope in context of this data.
Interpret the y-intercept in context of this data.
4. Use the prediction line to predict the temperature for Logan, Utah, given the latitude is 41.75 N.
5. Use the prediction line to predict the temperature for St. George, Utah, given the latitude is 37.1 N.
Your teacher will provide the actual average temperatures for Logan and St. George, Utah.
7. What factors could account for why the actual average temperature in Logan is below the predicted
temperature, and reasons why St. George is above the predicted temperature?