National Weather Service United States Department of Commerce

Phoenix, AZ

Weather Forecast Office

Phoenix Rainfall Index       
EXPERIMENTAL
The Phoenix Rainfall Index
Updated: 07:05 GMT on 25 Apr 2015
Yesterday's PRI 0.04"
Number of Stations
With Rain (S)
70 of 128
(54.69%)
Areal Average Precipitation (I) 0.08"
One-Gage Maximum 0.47"
PRI Since Apr 1 0.04"
PRI Since Jan 1 1.71"
PRI Since Oct 1 2.89"


What is the PRI?
Normals
Records
Historical Data
(Hide Extra Contents)
Yesterday's Rainfall Amounts
Click icons on map above for individual values.
rain gage 0.00" rain gage 0.01-0.09" rain gage 0.10-0.24" rain gage 0.25-0.49"
rain gage 0.50-0.74" rain gage 0.75-0.99" rain gage 1.00-1.49" rain gage 1.50-1.99"
rain gage 2.00" +
Disclaimer KML Feedback Welcomed PDD Yesterday's Raw Data
ID,RAIN,LAT,LON 5400, 0.00, 33.434917, -112.334167 5405, 0.00, 33.511417, -112.323778 6810, 0.00, 33.447083, -112.555917 5415, 0.00, 33.533972, -112.471028 6820, 0.00, 33.450639, -112.494361 5430, 0.00, 33.567194, -112.558278 4920, 0.16, 33.887917, -111.953556 6530, 0.16, 33.305361, -111.845972 6595, 0.04, 33.168417, -111.841083 775, 0.00, 33.170833, -112.006028 5500, 0.24, 33.607389, -112.305694 5410, 0.00, 33.543972, -112.349417 5975, 0.08, 33.622361, -111.777417 5950, 0.16, 33.611139, -111.725139 5985, 0.04, 33.637111, -111.769194 5990, 0.04, 33.636639, -111.746556 5995, 0.08, 33.654306, -111.786139 5980, 0.04, 33.621250, -111.748722 5965, 0.04, 33.594556, -111.733194 5970, 0.16, 33.606417, -111.751056 6620, 0.00, 33.327694, -111.746694 6580, 0.08, 33.263083, -111.725639 6605, 0.00, 33.357333, -111.772750 5520, 0.12, 33.621611, -112.202639 4770, 0.08, 33.543639, -112.193556 5505, 0.00, 33.536639, -112.282222 6890, 0.04, 33.269472, -112.320944 6850, 0.00, 33.389056, -112.392472 6840, 0.08, 33.320333, -112.482139 6900, 0.00, 33.099250, -112.435417 6880, 0.12, 33.223389, -112.309528 6520, 0.39, 33.358306, -111.890861 6570, 0.04, 33.405528, -111.710361 4555, 0.16, 33.454583, -111.729306 4540, 0.08, 33.428111, -111.827000 4530, 0.20, 33.400861, -111.851944 6540, 0.28, 33.381944, -111.827333 4550, 0.47, 33.430639, -111.770444 4545, 0.04, 33.438139, -111.814056 6625, 0.00, 33.440000, -111.590333 4560, 0.43, 33.472972, -111.681639 6655, 0.20, 33.494806, -111.641083 6640, 0.00, 33.464750, -111.607556 6650, 0.35, 33.481278, -111.615861 5490, 0.04, 33.929278, -112.529750 5580, 0.12, 33.900972, -112.054972 5625, 0.08, 33.895944, -112.149583 780, 0.00, 33.087194, -111.686833 4805, 0.04, 33.513694, -111.999639 4790, 0.04, 33.536056, -111.974028 5525, 0.00, 33.583500, -112.239389 5595, 0.16, 33.637972, -112.239556 5610, 0.00, 33.735861, -112.225472 4815, 0.08, 33.579667, -112.054806 4810, 0.00, 33.543694, -112.051417 4820, 0.00, 33.584000, -112.154250 4835, 0.08, 33.572917, -112.104417 5535, 0.08, 33.677222, -112.154000 6550, 0.47, 33.327806, -111.989722 4900, 0.16, 33.717000, -112.044472 4830, 0.04, 33.599694, -112.112028 4915, 0.28, 33.792306, -111.996306 4500, 0.08, 33.369333, -112.142167 5550, 0.16, 33.690222, -112.066278 4800, 0.00, 33.562167, -112.031556 4700, 0.00, 33.426639, -112.118611 4645, 0.00, 33.669806, -112.025361 4680, 0.00, 33.646083, -112.039167 4655, 0.00, 33.649056, -112.010417 4665, 0.00, 33.627944, -112.080750 4715, 0.12, 33.478361, -112.117222 4840, 0.00, 33.625500, -112.129472 6500, 0.20, 33.371944, -111.970472 4690, 0.00, 33.581417, -111.968417 4640, 0.00, 33.603694, -112.004472 4710, 0.00, 33.446694, -112.079500 4775, 0.00, 33.531111, -112.113750 4760, 0.00, 33.498639, -112.187778 4780, 0.00, 33.516083, -112.048222 5630, 0.35, 33.863000, -112.184167 4745, 0.00, 33.461500, -111.982250 4740, 0.00, 33.459750, -111.968278 4650, 0.04, 33.654806, -112.007167 4730, 0.00, 33.478333, -112.014417 4850, 0.04, 33.601306, -112.072611 4510, 0.00, 33.400028, -112.070528 4515, 0.00, 33.426083, -111.995694 4755, 0.00, 33.399806, -112.204028 5565, 0.04, 33.730083, -112.119750 6560, 0.00, 33.315167, -112.133639 6510, 0.04, 33.344389, -112.033083 6525, 0.31, 33.346833, -112.084583 4635, 0.00, 33.581694, -111.984528 4720, 0.00, 33.477694, -112.041472 4750, 0.00, 33.479694, -111.978889 6710, 0.00, 33.230278, -111.594278 6615, 0.00, 33.220139, -111.647000 6610, 0.00, 33.261472, -111.628861 4580, 0.12, 33.505111, -111.787139 5900, 0.24, 33.717639, -111.684222 4695, 0.04, 33.610056, -111.865444 4930, 0.24, 33.852972, -111.864389 5930, 0.00, 33.761111, -111.813833 4625, 0.00, 33.507778, -111.936389 4610, 0.04, 33.534444, -111.914222 4615, 0.00, 33.495083, -111.911222 4620, 0.00, 33.533167, -111.897889 4600, 0.12, 33.449222, -111.914833 4675, 0.08, 33.563667, -111.899722 4660, 0.16, 33.588194, -111.806389 5915, 0.28, 33.700667, -111.745278 4605, 0.00, 33.485111, -111.942667 4670, 0.00, 33.728417, -111.893250 4590, 0.08, 33.654667, -111.895500 4595, 0.16, 33.667917, -111.867056 4935, 0.04, 33.734472, -111.843639 5945, 0.00, 33.644417, -111.812139 4630, 0.00, 33.610556, -111.922444 5515, 0.04, 33.665472, -112.356667 5510, 0.00, 33.636778, -112.341250 5445, 0.31, 33.677000, -112.423500 5435, 0.12, 33.685306, -112.408639 5465, 0.04, 33.681056, -112.476000 5450, 0.00, 33.734944, -112.577194 4525, 0.28, 33.412972, -111.930861 4520, 0.00, 33.433972, -111.961333 4765, 0.00, 33.441194, -112.221917 5455, 0.12, 33.770500, -112.521028
Phoenix, Arizona is a vast, sprawling metropolis which covers an area of approximately 5000 km² (1900 mi²). Historically, the official rain gauge for the Phoenix Metropolitan Area (PMA) has been situated near the center of the city. Since 1933, the official rain gauge has resided at Phoenix Sky Harbor International Airport (KPHX). While KPHX may have adequately represented Phoenix for the first half of the 20th century, it has become apparent that a single observation station can no longer properly represent the spatial and temporal distribution of precipitation over the PMA, especially during single day summer convective events associated with the North American Monsoon. In order to better represent rainfall across the PMA, and compare and contrast precipitation events over the PMA, a Phoenix Rainfall Index (PRI) has been created.

The PRI, based on precipitation observed at up to 132 ALERT rain gauges across the PMA (operated by the Flood Control District of Maricopa County), incorporates both a spatial coverage term (S) and a precipitation intensity/magnitude term (I). It should be noted that the rain gages measure precipitation in millimeters (increments of 0.04"). Therefore, any precipitation less than 1 mm/0.04" will likely not be measured by the rain gages. Coupled with mathematical rounding, it is very likely there will be days when precipitation falls across the PMA yet the PRI is 0.00". When this happens it is reflective of either a very light or very isolated precipitation event. Also, please be aware that the rainfall data are only passed through minimal quality control mechanisms. The most common error will be light precip amounts at individual gages when no rain actually occurred.

A ten year climatology of the PRI reveals that it sufficiently captures the annual trends in precipitation events across the PMA, while daily records adequately showcase extreme precipitation events. Daily calculation and dissemination of the PRI should be a very useful tool for the local Weather and Climate Enterprise. The PRI dataset may also be useful for research related to precipitation across the PMA.
DayJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC
10.020.030.030.020.010.000.010.020.010.010.020.01
20.020.030.030.020.010.000.010.020.010.010.020.01
30.020.030.030.020.000.000.010.020.010.020.020.01
40.020.030.030.020.000.000.010.020.010.020.020.01
50.020.030.030.020.000.000.010.020.010.020.020.01
60.020.030.030.020.000.000.010.020.010.020.020.01
70.020.030.030.020.000.000.010.020.010.020.010.01
80.020.030.030.020.000.000.010.020.010.020.010.01
90.020.030.030.010.000.000.010.020.010.020.010.01
100.020.030.030.010.000.000.020.020.010.020.010.01
110.020.030.030.010.000.000.020.020.010.020.010.01
120.020.030.030.010.000.000.020.020.010.020.010.01
130.020.030.030.010.000.000.020.020.010.020.010.01
140.020.030.030.010.000.000.020.020.010.020.010.01
150.030.030.030.010.000.000.020.020.010.020.010.01
160.030.030.030.010.000.000.020.020.010.020.010.01
170.030.030.020.010.000.000.020.020.010.020.010.02
180.030.030.020.010.000.000.020.020.010.020.010.02
190.030.030.020.010.000.000.020.020.010.020.010.02
200.030.030.020.010.000.000.020.010.010.020.010.02
210.030.030.020.010.000.000.020.010.010.020.010.02
220.030.030.020.010.000.000.020.010.010.020.010.02
230.030.030.020.010.000.000.020.010.010.020.010.02
240.030.030.020.010.000.010.020.010.010.020.010.02
250.030.030.020.010.000.010.020.010.010.020.010.02
260.030.030.020.010.000.010.020.010.010.020.010.02
270.030.030.020.010.000.010.020.010.010.020.010.02
280.030.030.020.010.000.010.020.010.010.020.010.02
290.030.030.020.010.000.010.020.010.010.020.010.02
300.030.020.010.000.010.020.010.010.020.010.02
310.030.020.000.020.010.020.02
Sum0.790.960.780.360.040.060.510.490.340.520.410.47
Top 5 Daily Values by Month
Month Spatial (S)
(percent)
Intensity (I)
(inches)
Phoenix Rainfall
Index (PRI)
(inches)
JAN 1. 3 JAN 2005 - 1.00
2. 3 JAN 2005 - 1.00
3. 26 JAN 2005 - 1.00
4. 7 JAN 2008 - 1.00
5. 27 JAN 2008 - 1.00
1. 21 JAN 2010 - 1.66
2. 27 JAN 2008 - 1.32
3. 3 JAN 2005 - 0.90
4. 27 JAN 2001 - 0.76
5. 4 JAN 2005 - 0.57
1. 21 JAN 2010 - 1.66
2. 27 JAN 2008 - 1.32
3. 3 JAN 2005 - 0.90
4. 27 JAN 2001 - 0.76
5. 4 JAN 2005 - 0.57
FEB 1. 13 FEB 2003 - 1.00
2. 25 FEB 2003 - 1.00
3. 11 FEB 2005 - 1.00
4. 28 FEB 2005 - 1.00
5. 19 FEB 2005 - 1.00
1. 13 FEB 2003 - 1.54
2. 11 FEB 2005 - 0.99
3. 19 FEB 2005 - 0.83
4. 25 FEB 2003 - 0.74
5. 23 FEB 2004 - 0.73
1. 13 FEB 2003 - 1.54
2. 11 FEB 2005 - 0.99
3. 19 FEB 2005 - 0.83
4. 25 FEB 2003 - 0.74
5. 23 FEB 2004 - 0.72
MAR 1. 16 MAR 2003 - 1.00
2. 5 MAR 2005 - 1.00
3. 7 MAR 2001 - 0.99
4. 11 MAR 2006 - 0.99
5. 22 MAR 2007 - 0.99
1. 11 MAR 2006 - 1.40
2. 6 MAR 2000 - 1.27
3. 7 MAR 2001 - 0.80
4. 22 MAR 2007 - 0.70
5. 5 MAR 2000 - 0.65
1. 11 MAR 2006 - 1.39
2. 6 MAR 2000 - 1.24
3. 7 MAR 2001 - 0.79
4. 22 MAR 2007 - 0.69
5. 5 MAR 2000 - 0.63
APR 1. 1 APR 1999 - 0.98
2. 2 APR 1999 - 0.98
3. 21 APR 2001 - 0.98
4. 2 APR 2004 - 0.98
5. 23 APR 2005 - 0.98
1. 2 APR 2004 - 1.12
2. 2 APR 1999 0 0.59
3. 5 APR 2001 - 0.39
4. 11 APR 2009 - 0.38
5. 1 APR 1999 - 0.26
1. 2 APR 2004 - 1.11
2. 2 APR 1999 - 0.58
3. 11 APR 2009 - 0.36
4. 5 APR 2001 - 0.34
5. 1 APR 1999 - 0.26
MAY 1. 22 MAY 2009 - 0.95
2. 23 MAY 2008 - 0.94
3. 21 MAY 2009 - 0.75
4. 22 MAY 2008 - 0.64
5. 24 MAY 2008 - 0.54
1. 22 MAY 2008 - 0.23
2. 22 MAY 2009 - 0.18
3. 23 MAY 2008 - 0.15
4. 21 MAY 2009 - 0.09
5. 24 MAY 2008 - 0.03
1. 22 MAY 2009 - 0.17
2. 22 MAY 2008 - 0.15
3. 23 MAY 2008 - 0.14
4. 21 MAY 2009 - 0.07
5. 24 MAY 2008 - 0.02
JUN 1. 28 JUN 2000 - 0.53
2. 22 JUN 2000 - 0.50
3. 2 JUN 1999 - 0.46
4. 29 JUN 2000 - 0.34
5. 20 JUN 2000 - 0.33
1. 28 JUN 2000 - 0.12
2. 20 JUN 2000 - 0.08
3. 23 JUN 2000 - 0.07
4. 22 JUN 2000 - 0.06
5. 2 JUN 1999 - 0.06
1. 28 JUN 2000 - 0.06
2. 22 JUN 2000 - 0.03
3. 20 JUN 2000 - 0.03
4. 2 JUN 1999 - 0.03
5. 29 JUN 2000 - 0.02
JUL 1. 10 JUL 2008 - 0.99
2. 14 JUL 1999 - 0.95
3. 30 JUL 2001 - 0.95
4. 29 JUL 2003 - 0.95
5. 15 JUL 1999 - 0.93
1. 10 JUL 2008 - 0.80
2. 14 JUL 1999 - 0.60
3. 25 JUL 2006 - 0.54
4. 14 JUL 2002 - 0.49
5. 29 JUL 2003 - 0.44
1. 10 JUL 2008 - 0.80
2. 14 JUL 1999 - 0.57
3. 25 JUL 2006 - 0.44
4. 29 JUL 2003 - 0.42
5. 14 JUL 2002 - 0.41
AUG 1. 2 AUG 2005 - 0.99
2. 14 AUG 2003 - 0.97
3. 3 AUG 2005 - 0.97
4. 25 AUG 2008 - 0.95
5. 12 AUG 2006 - 0.94
1. 2 AUG 2005 - 1.01
2. 28 AUG 2008 - 0.54
3. 14 AUG 2003 - 0.51
4. 25 AUG 2008 - 0.50
5. 7 AUG 2008 - 0.47
1. 2 AUG 2005 - 1.00
2. 14 AUG 2003 - 0.49
3. 25 AUG 2008 - 0.48
4. 7 AUG 2008 - 0.43
5. 28 AUG 2008 - 0.41
SEP 1. 19 SEP 1999 - 0.98
2. 2 SEP 2006 - 0.97
3. 7 SEP 2002 - 0.93
4. 6 SEP 2002 - 0.90
5. 4 SEP 1998 - 0.86
1. 2 SEP 2006 - 0.51
2. 19 SEP 1999 - 0.40
3. 6 SEP 2002 - 0.36
4. 19 SEP 2004 - 0.34
5. 7 SEP 2002 - 0.30
1. 2 SEP 2006 - 0.49
2. 19 SEP 1999 - 0.39
3. 6 SEP 2002 - 0.32
4. 19 SEP 2004 - 0.30
5. 7 SEP 2002 - 0.28
OCT 1. 21 OCT 2004 - 1.00
2. 28 OCT 2004 - 1.00
3. 21 OCT 2000 - 0.98
4. 22 OCT 2000 - 0.98
5. 27 OCT 2000 - 0.98
1. 27 OCT 2000 - 0.74
2. 22 OCT 2000 - 0.68
3. 28 OCT 2004 - 0.47
4. 10 OCT 2000 - 0.47
5. 10 OCT 2003 - 0.37
1. 27 OCT 2000 - 0.72
2. 22 OCT 2000 - 0.66
3. 28 OCT 2004 - 0.47
4. 10 OCT 2000 - 0.43
5. 21 OCT 2004 - 0.33
NOV 1. 22 NOV 2004 - 1.00
2. 30 NOV 2007 - 1.00
3. 29 NOV 2002 - 0.99
4. 12 NOV 2003 - 0.98
5. 27 NOV 2008 - 0.98
1. 30 NOV 2007 - 1.55
2. 12 NOV 2003 - 0.80
3. 29 NOV 2002 - 0.34
4. 27 NOV 2008 - 0.34
5. 22 NOV 2004 - 0.29
1. 30 NOV 2007 - 1.55
2. 12 NOV 2003 - 0.78
3. 29 NOV 2002 - 0.33
4. 27 NOV 2008 - 0.33
5. 22 NOV 2004 - 0.29
DEC 1. 4 DEC 2001 - 1.00
2. 4 DEC 2004 - 1.00
3. 6 DEC 2004 - 1.00
4. 29 DEC 2004 - 1.00
5. 5 DEC 2004 - 0.99
1. 29 DEC 2004 - 0.69
2. 4 DEC 2001 - 0.58
3. 16 DEC 2008 - 0.49
4. 7 DEC 2007 - 0.36
5. 8 DEC 2007 - 0.34
1. 29 DEC 2004 - 0.69
2. 4 DEC 2001 - 0.58
3. 16 DEC 2008 - 0.48
4. 7 DEC 2007 - 0.35
5. 8 DEC 2007 - 0.31
Top 5 Seasonal Values
Monsoon
(JUN 15 - SEP 30)
1. 2008 - 3.01
2. 1999 - 2.49
3. 2006 - 2.39
4. 2005 - 1.81
5. 2002 - 1.52
Winter
(DEC 1 - MAR 31)
1. 2004-2005 - 7.76
2. 2002-2003 - 4.79
3. 2007-2008 - 3.69
4. 2000-2001 - 3.56
5. 2008-2009 - 2.49
Daily PRI values from 1 June 1998 through yesterday.