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Tall Timbers Long-Term Weather Data

By Ron Masters, PhD, Director of Research

Tall Timbers and Red Hills Climate

The Red Hills region where Tall Timbers is located has a temperate sub-tropical climate. Summers are warm to hot and humid: winters are short and mild. Due to the proximity of the Gulf of Mexico (approximately 50 miles or 80 kilometers), relative humidity is high. Convective thunderstorms characterize the warm months, especially May through September. Continental frontal activity characterizes the cool season during October through April.

Figure 1. Tall Timbers annual rainfall from 1878 to 2010.

Figure 1. Tall Timbers annual rainfall from 1878 to 2010.

Figure2. Wade Tract annual rainfall from 1878 to 2010.

Figure2. Wade Tract annual rainfall from 1878 to 2010.

Figure 3. Average maximum and minimum monthly temperature show December, January and February are the coolest months and May through September as the hottest.

Figure 3. Average maximum and minimum monthly temperature show December, January and February are the coolest months and May through September as the hottest.

Figure 4. The frequency of hurricanes and tropical storms by decade that have tracked within 50 miles of Tall Timbers Research Station.

Figure 4. The frequency of hurricanes and tropical storms by decade that have tracked within 50 miles of Tall Timbers Research Station.

Figure 5. The monthly frequency of hurricanes and tropical storms that have tracked within 50 miles of Tall Timbers Research Station.

Figure 5. The monthly frequency of hurricanes and tropical storms that have tracked within 50 miles of Tall Timbers Research Station.

Figure 6. Tall Timbers Keetch-Byram Drought Index from 2006 to 2010. This data illustrates the cyclic nature of soil moisture and thus growing conditions. This index is also an important parameter to consider when planning a prescribed burn. Numbers above 700 indicate extreme drought conditions while 0 indicates completely saturated soil conditions

Figure 6. Tall Timbers Keetch-Byram Drought Index from 2006 to 2010. This data illustrates the cyclic nature of soil moisture and thus growing conditions. This index is also an important parameter to consider when planning a prescribed burn. Numbers above 700 indicate extreme drought conditions while 0 indicates completely saturated soil conditions

The long-term (since 1878) average annual rainfall at Tall Timbers is 53.5 inches and for the Wade Tract 54.2 (Figure 1 and 2). Rainfall is somewhat evenly distributed in most months ranging from 3.0 to 6.2 inches throughout the year except for 2 drier periods. Each of the following months average less than 4.0 inches, April and May and October through December. During the summer months most of the rainfall that this area receives is from isolated and localized thunderstorms that develop along the Gulf Coast and move north. However, we do occasionally receive rain from thunderstorms that develop along the Atlantic coast and move east to west and the occasional hurricane or tropical storm. This creates a high degree of variability during the summer months across even as small an area as the Red Hills. In January through April and in October through December rainfall patterns are very similar across the Red Hills and the surrounding region with stations within a 25 mile radius of Tall Timbers exhibiting a high degree of similarity to Tall Timbers and often very close to actual observations from Tall Timbers.
The average temperature is 68°F, with extremes of 106°F and 8°F on Tall Timbers. The first freeze occurs around November 25 and the last freeze around March 3 on average. December, January and February are the coolest months and May through September the hottest (Figure 3). The total average growing season extends about 280 days.

Major weather events such as hurricanes, tornadoes, droughts, and floods occur infrequently. Those that track within 50 miles typically influence Tall Timbers weather, sometimes significantly. We average 4.5 tropical storms and 3.5 hurricanes per decade within this 50 mile radius (Figure 4). September is the month with the highest frequency of hurricanes and tropical storms (Figure 5).

Weather data contain many important environmental variables that are essential to monitor when conducting research whether long-term or short-term. It is basic data which helps to understand changes we may witness in plant community and thus wildlife community data through time. Departure from average (what weather scientists report as normal) may be more important in terms of its immediate impact on plant communities and thus wildlife communities than long-term averages. Therefore variability and extremes are important data that we monitor. When conducting an experiment it is important to know if the experimental manipulation causes the effect or if the outcome of the experiment is related to weather.

The Tall Timbers Long-term Weather Database includes data for Tall Timbers Research Station and the Wade Tract.

Annual and monthly summaries for both stations date back to 1878 (Figures 1 and 2). Daily summaries are from 1930 forward and include daily precipitation, maximum temperature and minimum temperature, maximum and minimum relative humidity, and the Keetch-Byram Drought Index (KBDI) (Figure 6).

Development and History of the Dataset

Prior to 1968 weather data was based on a weighted average of available weather data from weather stations within 21 miles of Tall Timbers. Tall Timbers was established as a NOAA weather station site in 1968. It was maintained as a NOAA site until the end of 1997. Daily readings of rainfall, maximum and minimum, air temperature, soil temperature, and relative humidity were taken.

In 1998, a self recording weather station was put into use. In 2003, a more sophisticated station was added in a different location on the station with a sensor array that met RAWS standards. In 2010, a duplicate station was deployed to serve as a back-up in the event that one station was down for servicing or damaged by severe weather for a period of time. These stations record observations hourly.

For the Wade Tract daily weather is from Thomasville which is ~6 miles from the preserve center. A portable weather station was deployed for a short period of time on the Wade tract during the late 1990s and early 2000s.

This data was used when available.

Regional data included in this data set include the Palmer Drought Severity Index. Because tropical storms and hurricanes strongly influence local weather patterns, we have noted all such storms since 1930 that have tracked within a 50 mile radius of Tall Timbers.

Data Availability

Monthly weather summaries may be made available only to visiting scientists conducting research on the station.