PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
225 PM CDT WED JUL 6 2011
...1981-2010 CLIMATE NORMALS RELEASED ON JULY 1ST...
...AVERAGE MONTHLY LOW TEMPERATURES TRENDING WARMER...
THE 30 YEAR CLIMATE NORMALS ARE UPDATED ONCE A DECADE AND THE
DECADE OF THE 1970`S HAS BEEN REPLACED WITH THE 2000`S. THE PREVIOUS
30 YEAR CLIMATE NORMALS (1970-2000) WILL BE REPLACED WITH THE
1981-2010 NORMALS EFFECTIVE AUGUST 1ST 2011. NEW NORMALS HAVE BEEN
PREPARED FOR THE CITY OF HOUSTON (HOUSTON INTERCONTINENTAL
AIRPORT)...HOUSTON HOBBY AIRPORT...COLLEGE STATION AND GALVESTON.
NEW NORMALS HAVE ALSO BEEN CALCULATED FOR OUR NETWORK OF CO-OP SITES.
THE DAILY CLIMATE MESSAGE (CLIHOU...CLIGLS AND CLICLL) PROVIDES
AVERAGE HIGH TEMPERATURE DATA...AVERAGE LOW TEMPERATURE DATA...
AVERAGE DAILY DATA AND AVERAGE RAINFALL EXPECTED FOR A PARTICULAR
CALENDAR DAY. SINCE THE NEW NORMALS BECOME EFFECTIVE ON AUGUST
1ST...LET`S TAKE A LOOK AT HOW THE DAILY DATA WILL CHANGE FOR THAT
DATE FOR THE CITY OF HOUSTON:
AUG 1ST 1971-2000 AUG 1ST 1981-2010
AVG HIGH 94 95
AVG LOW 74 75
AVG DAILY 84 85
AVG PRECIP 0.10 0.10
MONTHLY NORMALS HAVE ALSO CHANGED WITH SOME MONTHS WARMER AND
OTHERS COOLER. SOME OF THE CHANGES MAY NOT MATCH PERCEPTIONS. THE
NEW 1981-2010 DATA WILL BE LISTED FIRST WITH THE PREVIOUS
1971-2000 NORMALS LISTED BELOW. WITHOUT FURTHER ADO...HERE ARE
THE NEW 1981-2010 MONTHLY CLIMATE STATISTICS:
CITY OF HOUSTON (IAH)
AVERAGE MONTHLY HIGH TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
62.9 66.3 73.0 79.6 86.3 91.4 93.7 94.5 89.7 82.0 72.5 64.3
62.3 66.5 73.3 79.1 85.5 90.7 93.6 93.5 89.3 82.0 72.0 64.6
+0.6 -0.2 -0.3 +0.5 +0.8 +0.7 +0.1 +1.0 +0.2 +0.0 +0.5 -0.3
CITY OF HOUSTON (IAH)
AVERAGE MONTHLY LOW TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
43.2 46.5 52.5 59.4 67.6 73.3 75.1 74.8 69.8 60.9 52.1 44.6
41.2 44.3 51.3 57.9 66.1 71.8 73.5 73.0 68.4 58.8 49.8 42.8
+2.0 +2.2 +1.2 +1.5 +1.5 +1.5 +1.6 +1.8 +1.4 +2.1 +2.3 +1.8
CITY OF HOUSTON (IAH)
AVERAGE MONTHLY TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
53.1 56.4 62.7 69.5 76.9 82.4 84.4 84.6 79.8 71.5 62.3 54.4
51.8 55.4 62.3 68.5 75.8 81.3 83.6 83.3 78.9 70.4 60.9 53.7
+1.3 +1.0 +0.4 +1.0 +1.1 +1.1 +0.8 +1.3 +0.9 +1.1 +1.4 +0.7
CITY OF HOUSTON (IAH)
AVERAGE MONTHLY RAINFALL
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
3.38 3.20 3.41 3.31 5.09 5.93 3.79 3.76 4.12 5.70 4.34 3.74
3.68 3.88 3.36 3.60 5.15 5.35 3.18 3.83 4.33 4.50 4.19 3.69
MISCELLANEOUS DATA (1981-2010):
AVERAGE NUMBER OF DAYS ABOVE 100 DEGREES - 4
AVERAGE NUMBER OF DAYS ABOVE 90 DEGREES - 102
AVERAGE NUMBER OF DAYS BELOW 32 DEGREES - 10
AVERAGE NUMBER OF DAYS BELOW 20 DEGREES - 0.3
CAN ANY CONCLUSIONS BE DRAWN FROM THIS DATA? NOT REALLY...BUT A
FEW TRENDS ARE RATHER APPARENT. SPRING AND SUMMER ARE TRENDING
WARMER. OVERNIGHT LOW TEMPERATURES ARE TRENDING CONSIDERABLY
WARMER PARTICULARLY IN THE WINTER MONTHS. WHY THE WARM-UP? THERE
ARE A NUMBER OF POSSIBLE REASONS. THERE HAS BEEN AN INCREASE IN
URBANIZATION NEAR THE OBSERVATION SITE. THERE HAS ALSO BEEN A
CHANGE IN INSTRUMENTATION BETWEEN 1970 AND 2010. THE 1970S WERE A
VERY COLD DECADE AND THE TEMPERATURE VALUES FROM THE 1970S HAVE
DROPPED OFF AND THE WARMER 2000`S HAVE BEEN ADDED. THESE FACTORS
PLUS SEVERAL OTHERS MAY HAVE CONTRIBUTED TO THE WARMING.
LOOKING AT THE AVERAGE HIGH TEMPERATURES...AUGUST SHOWED THE
LARGEST CHANGE WITH AN INCREASE OF +1.0 DEGREES. THE LARGEST
INCREASE IN AVERAGE LOW TEMPERATURES OCCURRED IN NOVEMBER WITH A
2.3 DEGREE WARM-UP OVER THE PREVIOUS CLIMATE NORMALS. DESPITE THE
RECENT DROUGHT...HEAVY RAIN EVENTS DO OCCUR HERE. THE AVERAGE
RAINFALL IN OCTOBER IS NOW 5.70 INCHES WHICH IS AN INCREASE OF
1.20 INCHES OVER THE PREVIOUS OCTOBER RAINFALL. THE WETTEST MONTH
OF THE YEAR IS STILL JUNE.
GALVESTON (GLS)
AVERAGE MONTHLY HIGH TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
61.8 64.3 70.2 75.9 83.0 88.2 89.6 90.3 87.4 80.6 71.6 63.9
61.9 64.4 70.0 75.2 81.4 86.6 88.7 89.3 86.5 79.7 71.3 64.3
-0.1 -0.1 +0.2 +0.7 +1.6 +1.6 +0.9 +1.0 +0.9 +0.9 +0.3 -0.4
GALVESTON (GLS)
AVERAGE MONTHLY LOW TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
48.6 50.9 56.6 64.4 72.3 77.5 79.4 79.7 75.9 68.1 58.6 50.7
49.7 51.5 58.2 64.7 72.3 77.8 79.8 79.5 75.6 68.4 59.4 51.8
-1.1 -0.6 -1.6 -0.3 0.0 -0.3 -0.4 +0.2 +0.3 -0.3 -0.8 -1.1
GALVESTON (GLS)
AVERAGE MONTHLY TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
55.2 57.6 63.4 70.1 77.6 82.9 84.5 85.0 81.6 74.3 65.1 57.3
55.8 58.0 64.1 70.0 76.9 82.2 84.3 84.4 81.1 74.1 65.4 58.1
-0.6 -0.4 -0.7 +0.1 +0.7 +0.7 +0.2 +0.6 +0.5 +0.2 -0.3 -0.8
GALVESTON (GLS)
AVERAGE MONTHLY RAINFALL
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
4.20 2.57 3.16 3.05 4.32 5.69 3.80 4.39 6.03 5.52 4.51 3.52
4.08 2.61 2.76 2.56 3.70 4.04 3.45 4.22 5.76 3.49 3.64 3.53
MISCELLANEOUS DATA (1981-2010):
AVERAGE NUMBER OF DAYS ABOVE 100 DEGREES - 0.2
AVERAGE NUMBER OF DAYS ABOVE 90 DEGREES - 45
AVERAGE NUMBER OF DAYS BELOW 32 DEGREES - 0.7
AVERAGE NUMBER OF DAYS BELOW 20 DEGREES - 0
THE OBSERVATION SITE MOVED FROM THE POST OFFICE BUILDING IN
DOWNTOWN GALVESTON TO SCHOLES FIELD IN THE MID 1990S. WITHOUT THE
ADDITIONAL HEAT FROM URBANIZATION...OVERNIGHT LOWS TRENDED COOLER
IN THE FALL AND WINTER. RAINFALL JOLTED UPWARD. THE ANNUAL
RAINFALL FOR 30 YEAR PERIOD IS NOW 50.76 INCHES. THE PREVIOUS 30
YEAR RAINFALL AVERAGE WAS 43.84 INCHES. MORE RAIN FALLS IN
SEPTEMBER...OCTOBER AND NOVEMBER NOW THAN IN MARCH...APRIL AND
MAY.
COLLEGE STATION (CLL)
AVERAGE MONTHLY HIGH TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
61.0 64.8 71.7 78.9 85.8 91.7 94.8 96.2 90.5 81.4 71.0 62.3
60.6 65.5 72.6 78.8 85.3 91.7 95.6 96.2 90.9 82.0 70.9 62.8
+0.4 -0.7 -0.9 +0.1 +0.5 +0.0 -0.8 +0.0 -0.4 -0.6 +0.1 -0.5
COLLEGE STATION (CLL)
AVERAGE MONTHLY LOW TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
41.2 44.4 51.0 58.1 66.6 72.7 74.6 74.5 69.4 60.3 50.5 42.2
39.8 43.4 50.5 56.9 65.3 71.5 73.6 73.2 68.5 59.0 49.1 41.5
+1.4 +1.0 +0.5 +1.2 +1.3 +1.2 +1.0 +1.3 +0.9 +1.3 +1.4 +0.7
COLLEGE STATION (CLL)
AVERAGE MONTHLY TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
51.1 54.6 61.4 68.5 76.2 82.2 84.7 85.3 80.0 70.8 60.8 52.2
50.2 54.5 61.6 67.9 75.3 81.6 84.6 84.7 79.7 70.5 60.0 52.2
+0.9 +0.1 -0.2 +0.6 +0.9 +0.6 +0.1 +0.6 +0.3 +0.3 +0.8 +0.0
COLLEGE STATION (CLL)
AVERAGE MONTHLY RAINFALL
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
3.24 2.85 3.17 2.66 4.33 4.45 2.14 2.68 3.18 4.91 3.22 3.23
3.32 2.38 2.84 3.20 5.05 3.79 1.92 2.63 3.91 4.22 3.18 3.23
MISCELLANEOUS DATA (1981-2010):
AVERAGE NUMBER OF DAYS ABOVE 100 DEGREES - 12
AVERAGE NUMBER OF DAYS ABOVE 90 DEGREES - 106
AVERAGE NUMBER OF DAYS BELOW 32 DEGREES - 14
AVERAGE NUMBER OF DAYS BELOW 20 DEGREES - 1.0
MONTHLY LOW TEMPERATURES TRENDED WARMER BUT MONTHLY HIGH
TEMPERATURES WERE FAIRLY NEUTRAL...NOT SHOWING MUCH WARMING OR
COOLING. THE 1981-2010 ANNUAL RAINFALL AVERAGE WAS 40.06 INCHES
WHICH IS 0.39 INCHES GREATER THAN THE PREVIOUS 1971-2000 ANNUAL
AVERAGE OF 39.67 INCHES.
HOBBY AIRPORT (HOU)
AVERAGE MONTHLY HIGH TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
63.0 66.0 72.4 78.8 85.4 90.1 92.1 92.6 88.4 81.2 72.4 64.5
HOBBY AIRPORT (HOU)
AVERAGE MONTHLY LOW TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
45.1 48.5 54.3 60.9 68.7 73.9 75.5 75.7 71.7 63.1 53.9 46.7
HOBBY AIRPORT (HOU)
AVERAGE MONTHLY TEMPERATURE
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
54.1 57.3 63.3 69.8 77.0 82.0 83.8 84.2 80.1 72.1 63.2 55.6
HOBBY AIRPORT (HOU)
AVERAGE MONTHLY RAINFALL
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
3.87 3.21 3.20 3.25 4.75 7.10 4.66 5.06 5.21 5.99 4.32 4.03
MISCELLANEOUS DATA (1981-2010):
AVERAGE NUMBER OF DAYS ABOVE 100 DEGREES - 1.3
AVERAGE NUMBER OF DAYS ABOVE 90 DEGREES - 84
AVERAGE NUMBER OF DAYS BELOW 32 DEGREES - 5
AVERAGE NUMBER OF DAYS BELOW 20 DEGREES - 0.3
$$
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