Climate of Big Bend National Park, Texas:
Laura Phillips
In the most general terms, southwestern Texas is a desert, part of the Chihuahuan Desert to be precise. It generally has cool, dry winters and hot, slightly less dry summers. The climate is controlled by shifting air currents: in the fall and winter, currents move down from the north and northwest carrying cold, dry air; in the spring and summer, weather patterns are dominated by air masses moving west and north off the Gulf of Mexico carrying moisture.
Thus, the rainy season is mid-June to October, with the maximum rainfall in July, usually. Annual precipitation ranges from less than 10” at low elevations along the river to 15-20” in the mountains. Rain falls mostly in locally heavy afternoon convective showers which can lead to flash-flooding. There is some precipitation in the winter as sleet or snow but not much. There is typically very little precipitation in March and April when temperatures are most favorable to plant growth.
Temperatures also vary across the elevation gradients of the park with as much as 10-20° difference from river to peaks. Large diurnal temperature changes are typical of the desert. Winters generally experience daily lows around 35° and highs around 65°, while in the summer the lows are typically around 65° with highs above 90°. Maximum high temperatures are usually reached in June, but there is a lag in the overnight temperatures which are greatest in July (at the same time the precipitation is at its highest).
Guadalupe Mountains National Park experiences the same general patterns as Big Bend, although its position a little north and, on average, at slightly greater elevation predisposes it to slightly lower temperatures year-round and slightly more precipitation, including more snow in the winter.
Big Bend Climate Characteristics
|
Month |
Ave. max. temp. (°F) |
Ave. min. Temp. (°F) |
Ave. monthly Precip. (in) |
Ave. Year-to-date precip. (in) |
|
January |
60.9 |
35.0 |
.46 |
.46 |
|
February |
66.2 |
37.8 |
.34 |
.80 |
|
March |
77.4 |
45.3 |
.31 |
1.11 |
|
April |
80.7 |
52.3 |
.70 |
1.81 |
|
May |
88.0 |
59.3 |
1.50 |
3.31 |
|
June |
94.2 |
65.5 |
1.93 |
5.24 |
|
July |
92.9 |
68.3 |
2.09 |
7.33 |
|
August |
91.1 |
66.4 |
2.35 |
9.68 |
|
September |
86.4 |
61.9 |
2.12 |
11.80 |
|
October |
78.8 |
52.7 |
2.27 |
14.07 |
|
November |
68.5 |
42.3 |
.70 |
14.77 |
|
December |
62.2 |
36.4 |
.57 |
15.34 |
(from http://www.nps.gov/bibe/weather.html)
Guadalupe Mountains Climate Characteristics
(From http://www.nps.gov/gumo/gumo/weather.html )
References:
http://www.nps.gov/bibe/weather.html
http://www.nps.gov/gumo/gumo/weather.html
Cottle, H.J. 1932. Vegetation on north and south slopes of mountains in southwestern Texas. Ecology 13(2):121-134.
Powell, A.M. 1988. Tree and shrubs of Trans-Pecos Texas. Big Bend Natural History Association, Inc.
Whitson, P.D. 1971. Dynamics of the shrub desert formation – succulent desert formation transition in Big Bend National Park, Texas. Ph.D. dissertation, University of Oklahoma.