National Rankings

National Data Info
Palmer Drought Severity Index (PDSI), Palmer Hydrological Drought Index (PHDI), and Palmer Modified Drought Index (PMDI) are not offered for multiple-month time scales.

Contiguous U.S.

Precipitation Rankings, September 2021

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  • Record Wettest
PeriodValue1901-2000
Mean		AnomalyRank
(1895-2022)		Wettest/Driest
Since		Record
September 2021
1-Month		2.39"
(60.71mm)		2.49"
(63.25mm)		-0.10"
(-2.54mm)		50th Driest
Driest since:
1956
79th Wettest
Wettest since:
1986
Ties: 1944
Aug–Sep 2021
2-Month		5.53"
(140.46mm)		5.11"
(129.79mm)		0.42"
(10.67mm)		99th Driest
Driest since:
1956
30th Wettest
Wettest since:
1977
Jul–Sep 2021
3-Month		8.94"
(227.08mm)		7.88"
(200.15mm)		1.06"
(26.93mm)		114th Driest
Driest since:
1930
15th Wettest
Wettest since:
1915
Jun–Sep 2021
4-Month		11.91"
(302.51mm)		10.81"
(274.57mm)		1.10"
(27.94mm)		110th Driest
Driest since:
1930
19th Wettest
Wettest since:
1915
May–Sep 2021
5-Month		14.89"
(378.21mm)		13.72"
(348.49mm)		1.17"
(29.72mm)		107th Driest
Driest since:
1956
22nd Wettest
Wettest since:
1915
Ties: 1981
Apr–Sep 2021
6-Month		16.95"
(430.53mm)		16.24"
(412.50mm)		0.71"
(18.03mm)		85th Driest
Driest since:
1956
44th Wettest
Wettest since:
1915
Ties: 1907
Mar–Sep 2021
7-Month		19.46"
(494.28mm)		18.75"
(476.25mm)		0.71"
(18.03mm)		82nd Driest
Driest since:
1956
47th Wettest
Wettest since:
1973
Feb–Sep 2021
8-Month		21.48"
(545.59mm)		20.88"
(530.35mm)		0.60"
(15.24mm)		78th Driest
Driest since:
1930
51st Wettest
Wettest since:
2019
Jan–Sep 2021
9-Month		23.57"
(598.68mm)		23.20"
(589.28mm)		0.37"
(9.40mm)		73rd Driest
Driest since:
1934
56th Wettest
Wettest since:
2019
Dec 2020–Sep 2021
10-Month		25.62"
(650.75mm)		25.54"
(648.72mm)		0.08"
(2.03mm)		60th Driest
Driest since:
1931
68th Wettest
Wettest since:
2019
Nov 2020–Sep 2021
11-Month		27.56"
(700.02mm)		27.77"
(705.36mm)		-0.21"
(-5.34mm)		56th Driest
Driest since:
1934
72nd Wettest
Wettest since:
2019
Oct 2020–Sep 2021
12-Month		29.74"
(755.40mm)		29.94"
(760.48mm)		-0.20"
(-5.08mm)		56th Driest
Driest since:
1934
72nd Wettest
Wettest since:
2019
Ties: 1897
Apr 2020–Sep 2021
18-Month		45.88"
(1,165.35mm)		46.20"
(1,173.48mm)		-0.32"
(-8.13mm)		50th Driest
Driest since:
1931
78th Wettest
Wettest since:
2019
Oct 2019–Sep 2021
24-Month		61.65"
(1,565.91mm)		59.92"
(1,521.97mm)		1.73"
(43.94mm)		82nd Driest
Driest since:
1918
45th Wettest
Wettest since:
2020
Oct 2018–Sep 2021
36-Month		98.16"
(2,493.26mm)		89.87"
(2,282.70mm)		8.29"
(210.56mm)		115th Driest
Driest since:
1956
11th Wettest
Wettest since:
2019
Oct 2017–Sep 2021
48-Month		129.23"
(3,282.44mm)		119.78"
(3,042.41mm)		9.45"
(240.03mm)		116th Driest
Driest since:
1956
9th Wettest
Wettest since:
2019
Oct 2016–Sep 2021
60-Month		162.59"
(4,129.79mm)		149.66"
(3,801.36mm)		12.93"
(328.43mm)		120th Driest
Driest since:
1956
4th Wettest
Wettest since:
2020

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