Puerto Rico Downscale Climate Data

This research project lead by Dr. Katharine Hayhoe of Texas Tech University explored the potential effects of climate change in various Caribbean islands by utilizing 32 different global climate models to simulate observed temperature and rainfall variability over the Caribbean and to generate future projections of temperature and precipitation for Puerto Rico. These future projections were analyzed in terms of model performance and changes projected for a range of global mean temperature targets, from +1 to +3°C relative to 1971-2000. Projected  changes  were divided  into  two  regions  for  temperature  (hot  coastal  and  more  temperate  inland)  and three  regions  for  precipitation  (dry  northern  coast,  dry  southern  coast,  and  wet  inland locations).

Results for Puerto Rico:

  • Rainfall is projected to decrease, particularly in the wet season, with more frequent dry days. Precipitation in the Puerto Rico and the central Caribbean is characterized by a summer wet season ranging from May to November, punctuated by a mid-summer drought (MSD).
  • The frequency of ‘moderate extreme’ precipitation (e.g., more than 1 inch of rain) is projected to decrease, while more extreme precipitation (e.g., more than 3 inches of rain in a day) is expected to become more common.
  • Puerto Rico is expected to warm faster than the global average, with increases in both mean and extreme temperatures, including days per year over 95°F and nights warmer than 85°F.
  • With just one degree increase in global temperature, 60% of the wet seasons are projected to be warmer than the historical maximum and, on average, there would be 100 more days over 85°F, 150 more days over 90°F and 35 more days over 95°F each year.
  • With a  two-degree  increase  in  global  temperature,  every  day  would be  warmer  than  the  historical median, 350 days per year will be warmer than the historical 1-in-4 warmest days and 300 days per year will be warmer than the historical 1-in-10 warmest days.
  • For a global mean temperature  increase  of  three  degrees,  Puerto  Rico’s  average  daytime  maximum temperature  is  projected  to  increase  by  up  to  +7°C  in  the  dry  season  and  +6°C  in  wet  season.
  • Increases are projected to be greater for inland locations as compared to coastal and for nighttime temperatures (over +8°C) compared to daytime.
  • Per degree global mean temperature change, temperature on the warmest day of the year is projected to increase by +3°C while cooling degree-days (a measure of air conditioning demand) are projected to increase by +600. The range of daily temperature is expected to increase, particularly in the wet season.
  • Projected temperature changes are large enough to affect temperature sensitive crops, species, and ecosystems, while the combined effects of changes in temperature and precipitation are likely to increase the demand for energy, the risk of water stress and drought, and the risk of impacts from heavy rainfall events.

Products available for download at Caribbean LCC Conservation Planning Atlas:  

  • Quantitative  dataset  of  raw  climate projections for long‐term weather stations in the Caribbean
  • Qualitative analysis of global climate model performance over the Caribbean
  • Quantitative analysis of projected climate changes for Puerto Rico stations

Reference: Hayhoe, K. Quantifying Key Drivers of Climate Variability and Change for Puerto Rico and the Caribbean. Final Report 1 Oct 2011-30 Sep 2012. 2013. 241 p. 

COMING SOON! New dataset of dynamically downscaled climate data for Puerto Rico & the US Virgin Islands!

The Department of Interior Southeast Climate Science Center is leading the project to create a suite of dynamically downscaled, nonhydrostatic climate model projections for the U.S. Caribbean region. Climate modelers at the University of North Carolina – Chapel Hill, Florida State University and the Southeast Climate Science Center at North Carolina State University, are working to develop this unique dataset that comprises more than 60 climate variables at 2-km resolution, a scale never completed before in the Caribbean.

PROJECT DETAILS: Developing multi-model ensemble projections of ecologically relevant climate variables for Puerto Rico and the US Caribbean

Photo: Joint workshop by the Caribbean Landscape Conservation Cooperative and USDA Caribbean Climate Hub in August 2016 in San Juan, Puerto Rico.


The term ‘climate’ refers to the larger, more long-term systems in which weather takes place. Describing the climate of a place includes things like temperature, precipitation and wind averaged out over a period of time (usually 30 years). Climate is measured using statistical means and averages and is often discussed in terms of long-term regional patterns, such as ‘warming trends in the Arctic.’ Weather, on the other hand, is usually talked about in terms of events that are much more localized and short term. Variations in local weather can often cause confusion about the overall state of the climate. For instance, Los Angeles recently experienced several days of heavy rain that resulted in localized flooding, however, if one looks at the region of Southern California over the last thirty years, one can clearly see a severe decline in average precipitation. The flooding, in this case, would be an example of an ‘extreme weather event,’ while the overall trend of warming and drying reflects the state of the climate.
Following the definitions above, ‘climate change’ refers to long-term changes in the average value of weather variables such as rainfall or temperature. Over its history, the earth’s climate has always been changing. Things like volcanic eruptions and solar variation have interacted over extremely long periods and led to certain periods on earth being warmer (such as the one we are in now), while in other periods much of the earth’s surface has been covered in ice. Today, when most people talk about climate change they are refer specifically to ‘human-induced climate change’. By studying ancient air samples that are trapped deep within the ice caps, scientist have been able to track concentrations of Greenhouse Gases in earth’s atmosphere over many centuries. Greenhouse gases act just like a greenhouse by letting energy from the sun enter, but not allowing some of it to escape by radiating back into space. Since the industrial revolution, humans have dramatically increased earth’s greenhouse gases through activities ranging from energy production to agriculture. This increase is having an effect on the global weather averages and thus many people are concerned about climate change.
Climate variability refers to deviations from the average climate of a region that may or may not reflect longer-term trends. Scientist measure weather conditions over 30 year periods in order to establish average weather conditions and track climate trends for a given area. However, any given day, season, or year can vary widely from these overall averages in terms of temperature, precipitation, or other indicators. It is even possible for areas to experience several consecutive years in which longer-term trends may seem to be changing (i.e. wetter years in the midst of a long-term drying trend, or cooler years during an overall warming period.) These variations can be caused by natural occurrences such as El Niño and La Niña patterns in the Pacific Ocean that have a profound effect on weather throughout North America and the Caribbean. Many places experience a wide range of variations within local weather patterns that can make understanding the overall climate difficult without examining long-term weather data. Statistically analyzing weather data over 30 year periods allows scientists to establish averages that are not influenced by day-to-day, or year-to-year climate variability.
‘Climate scientist’ can refer to any person who uses the scientific method and instruments to experiment, measure, and record long-term weather data. These people could be atmospheric chemists who study how various chemical molecules interact in our atmosphere, or climatologists, who study long-term trends in weather and the many factors that affect them. Climate scientists may work for public and/or private universities, government agencies, or even private companies.
Climate scientists have developed complex models predicting that the Caribbean will continue to experience increasing temperatures, rising sea levels, shifting rainfall patterns, and more intense tropical storms and hurricanes as a result of global climate change.
These changes threaten agriculture in the region in many different ways;
• shifting rainfall patterns are already producing prolonged droughts that can make costly irrigation necessary for more farmers,
• increasing temperatures can affect growing seasons and combine with drought to stress crops and decrease yields,
• more intense tropical storms and hurricanes can lead to damaged infrastructure, crops, and topsoil loss.
• presents a threat to food security on the islands
• increasing temperature can enable pests, disease, and invasive species that affect livestock, wildlife and plants
• sea level rise will affect coastal populations and prime agricultural lands.
• space for growth and migration on the islands is limited
• a majority of farms do not have the capacity or access to specialized expertise, information, research or equipment to adapt to climate change.”
In order to address and prepare for the challenges climate change poses to agriculture, the USDA is encouraging farmers to become part of their local Climate Hub network. The Hubs are working to connect farmers and agricultural advisors with the right people, tools, science, and information that they need to adapt to a changing world. Here in the Caribbean, we working with local extension services, the Department of Agriculture, the NRCS, and others to help develop and deliver tools that will help improve yields and bolster resilience in the face of our common challenges. We can’t do this without you! Please contact us at caribbeanclimatehub@gmail.com, let us know: 1) Who you are and what types of crops you are cultivating, 2) What are the most serious challenges you are facing, 3) What sources do you rely on for information and advice, 4) How can we best help you prepare for a changing climate?

Climate Change & Agriculture FACTSHEET