Dry Season and 'Green' Season in Costa Rica

Image from Costa Rica

Image courtesy Author Jeff Weigel

To identify the two seasons of Costa Rica through satellite precipitation data and relate their importance to the travel industry
Grade Level: 6 – 8
Estimated Time for Completing Activity: 50 minutes
Learning Outcomes:
  • Students will explore the seasonal changes in precipitation for the Costa Rican Region.
  • Students will use the Internet as a resource to locate and graph scientific data.
  • Students will generate and analyze satellite data for precipitation.
  • Familiarity with Internet access and computer use
  • Discussion of ecotourism in Costa Rica
  • Discussion about Earth’s water cycle
  • Computer with Internet access
  • World Map or Atlas
  • Printer
Lesson Links:

Weather in the Tropics is essentially a phenomenon of solar radiation and air circulation. Intense heat at the Equator puts air in motion and a world wide pattern of winds is established. Because Costa Rica is situated in Central America between a tropical 8 and 11 degrees North latitude, and is squeezed on both sides by the Pacific and Atlantic Oceans, interesting seasonal patterns of precipitation are created. There is a dry season, which runs from December through April. This is called ‘verano’ which translated from Spanish means ‘summer’. There is also a wet season called ‘invierno’, or ‘winter’, which runs from May through November. It is interesting to note that these seasonal descriptions are based on precipitation patterns, and that temperatures stay in the tropical range year round.

For tourists, the high season coincides with the dry season. It is less likely that you will get rained on, and animal life is easier to view with fewer water sources. During this season, reservations are harder to get, everything is relatively crowded, and prices are higher. This time provides a large boost to the Costa Rican economy. The wet season, on the other hand, has been dubbed the ‘Green Season’ by the tourism industry in hopes of luring more tourists to Costa Rica during this period of higher precipitation.

In this lesson, you will use historical satellite data for the Costa Rican (Central American) region. You will examine monthly precipitation averages over three years to look for seasonal patterns.


Part I: Graph Monthly Precipitation Data (2003 – 2006)

1. Click on the link above to the MY NASA DATA Live Access Server.
2. Click on the blue ‘Choose dataset’ tab.
3. Select Atmosphere, Precipitation, then Monthly Precipitation (TRMM). A color plot will appear in the LAS window.
4. In the compass rose boxes, located under the blue and white reference world map, enter the location 11N in the north and south positions, and 85W in the east and west positions.
5. Under ‘Line Plots’ select Time Series.
6. Set Date from Jan 2003 to Jan 2006 to capture 3 years of data.
7. Click the yellow ‘Update Plot’ tab.
8. A pop-up window will appear labeled Monthly Precipitation (TRMM) (mm per hour). Open a permanent link or save this series for discussion.

Part II: Create a Color Plot Comparison of Precipitation

1. Return to the LAS page. Under ‘Maps’, choose Latitude-Longitude.
2. Enter the latitude and longitude in the compass rose boxes as 5 N in the south position, 15 N in the north position, 75 W in the east position, and 95 W in the west position.
3. Set the Date for Jan 2006.
4. Click Update Plot.
5. A pop-up window will appear with a color plot Precipitation map for Jan 2006.
6. From the blue tabs across the top, click on the ‘Compare’ tab. There are now four windows where you may choose other months to compare. Leave one window as January, but change the other three to March, July, and October so that you may see other seasons.
7. Click ‘Update Plots’.


1. What patterns do you observe in the Monthly Precipitation graph?
2. Which months received the most rain? The least?
3. What is the difference (in mm per hr) between the highest and lowest monthly precipitation?
4. Which months are part of the ‘Green (Wet) Season’? Trace those months in green on your graph. Do the same in red for the ‘High (Dry) Season’.
5. Are there other countries in the region that are affected by the same seasonal pattern? Use the LAS information from Part II and an atlas to answer this question.


1. To emphasize the inquiry process, teacher may add the following Pre-Lesson activities:

a. Locate Costa Rica using Internet resources or an atlas and develop theories for the possible climate and seasons at that location.

b. Using travel web sites, compare the hotel rates in Costa Rica during different times of the year. Is there a difference and why?

2. Repeat Part I and Part II above using different date ranges to look for variation in the expected precipitation patterns. What could explain these differences?

3. Explore if any major hurricane has impacted Costa Rica. Write a report about how it may have affected the country and tourism.

Lesson plan contributed by Jeff Weigel, Hampton, Virginia

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