National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
CXUS55 KBOI 011855 AAA
CLMBOI

CLIMATE REPORT...UPDATED
NATIONAL WEATHER SERVICE BOISE ID
1255 PM MDT MON OCT 1 2012

.....................................................................

...THE BOISE ID CLIMATE SUMMARY FOR THE MONTH OF SEPTEMBER 2012...

         ...SEPTEMBER WAS VERY WARM...DRY AND SMOKY...

SEPTEMBER 2012 WAS THE THIRD CONSECUTIVE MONTH WITH AVERAGE MONTHLY
TEMPERATURES WELL ABOVE NORMAL. THE COMBINED MONTHS OF JUNE THROUGH
SEPTEMBER ENDED UP BEING THE WARMEST EVER. SEPTEMBER BY ITSELF TIED
FOR THE 6TH WARMEST EVER. A RECORD HIGH OF 95 DEGREES WAS TIED ON
SEPTEMBER 8TH AND THIS WAS FOLLOWED BY A 93F ON THE 9TH. NO MINIMUM
TEMPERATURE DURING THE MONTH FELL BELOW 44 DEGREES AT THE AIRPORT
ALTHOUGH OUTLYING AREAS IN THE TREASURE VALLEY DID SEE LOWS IN THE
MID TO UPPER 30S.

IN ADDITION TO THE SEPTEMBER WARMTH...IT WAS ALSO EXTREMELY DRY. THE
MEAGER TOTAL OF .05 HUNDREDTHS DURING THE MONTH WAS MORE THAN A HALF
INCH BELOW NORMAL. THE SEPTEMBER DRYNESS WAS A CONTINUATION OF THE
HOT DRY SUMMER OF 2012 WHICH STARTED BACK IN MID JUNE. THE THREE
MONTH COMBINATION OF JULY-AUGUST-SEPTEMBER RECORDED ONLY .12
HUNDREDTHS IN THE RAIN BUCKET MAKING THIS ONE OF THE DRIEST SUMMER/S
EVER RECORDED IN THIS AREA.

THE HOT DRY CONDITIONS MADE FOR AN ACTIVE FIRE SEASON THAT CONTINUED
UNABATED DURING SEPTEMBER. A STAGNANT UPPER AIR PATTERN ALLOWED
SMOKE FROM REGIONAL WILDFIRES TO FILL THE TREASURE VALLEY ON MANY
DAYS IN SEPTEMBER. ON AT LEAST 15 DAYS SMOKE WAS THE PREVAILING
WEATHER AND VISIBILITY WAS REDUCED TO 2 TO 3 MILES ON SEVERAL OF
THESE DAYS IN THE EARLY MORNING AND LATE NIGHT HOURS. THICK SMOKE
PRODUCED POOR AIR QUALITY THROUGH A GOOD PART OF THE MONTH AND THE
DEQ ISSUED AIR QUALITY ALERTS ON MANY OF THESE DAYS. FINALLY DURING
THE LAST COUPLE DAYS OF THE MONTH...STRONGER WINDS ALOFT IMPROVED
MIXING THROUGH A DEEPER LAYER ALLOWING SMOKE TO CLEAR AND IMPROVING
AIR QUALITY AS THE MONTH ENDED.
.....................................................................

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1878 TO 2012

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE
                                          NORMAL
.............................................................
TEMPERATURE (F)
HIGHEST            95   09/08
LOWEST             44   09/12
AVG. MAXIMUM     83.5              78.8     4.7
AVG. MINIMUM     53.7              51.0     2.7
MEAN             68.6              64.9     3.7
DAYS MAX >= 90      5
DAYS MAX <= 32      0
DAYS MIN <= 32      0
DAYS MIN <= 0       0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         2.93   1986
TOTALS           0.05              0.58   -0.53
DAYS >= .01         2
DAYS >= .10         0
DAYS >= .50         0
DAYS >= 1.00        0
GREATEST
 24 HR. TOTAL    0.04   09/23 TO 09/23
                        09/22 TO 09/23
                        09/23 TO 09/23

DEGREE_DAYS
HEATING TOTAL      17               103     -86       10
 SINCE 7/1         17               121    -104
COOLING TOTAL     134               100      34      211
 SINCE 1/1       1273               934     339
..............................................................

WIND (MPH)
AVERAGE WIND SPEED              5.6
RESULTANT WIND SPEED/DIRECTION   0/142
HIGHEST WIND SPEED/DIRECTION    20/340    DATE  09/28
HIGHEST GUST SPEED/DIRECTION    26/330    DATE  09/28

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM

AVERAGE RH (PERCENT)     32


-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

$$