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, May 2021

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  • Record Driest
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  • Record Wettest
Period Value 1901-2000
Mean		 Anomaly Rank
(1895-2022)		 Wettest/Driest
Since		 Record
May 2021
1-Month 		2.99"
(75.95mm)		 2.91"
(73.91mm)		 0.08"
(2.04mm)		 72nd Driest
Driest since:
 1934
57th Wettest
Wettest since:
 2019
Ties: 1927
Apr–May 2021
2-Month 		5.05"
(128.27mm)		 5.43"
(137.92mm)		 -0.38"
(-9.65mm)		 39th Driest
Driest since:
 1934
90th Wettest
Wettest since:
 1957
Ties: 1989
Mar–May 2021
3-Month 		7.56"
(192.02mm)		 7.94"
(201.68mm)		 -0.38"
(-9.66mm)		 48th Driest
Driest since:
 1925
81st Wettest
Wettest since:
 1957, 1991
Feb–May 2021
4-Month 		9.58"
(243.33mm)		 10.07"
(255.78mm)		 -0.49"
(-12.45mm)		 42nd Driest
Driest since:
 1925
87th Wettest
Wettest since:
 2019
Jan–May 2021
5-Month 		11.67"
(296.42mm)		 12.39"
(314.71mm)		 -0.72"
(-18.29mm)		 37th Driest
Driest since:
 1934
92nd Wettest
Wettest since:
 2019
Dec 2020–May 2021
6-Month 		13.72"
(348.49mm)		 14.73"
(374.14mm)		 -1.01"
(-25.65mm)		 33rd Driest
Driest since:
 1931
95th Wettest
Wettest since:
 2019
Nov 2020–May 2021
7-Month 		15.66"
(397.76mm)		 16.96"
(430.78mm)		 -1.30"
(-33.02mm)		 27th Driest
Driest since:
 1934
101st Wettest
Wettest since:
 1983
Ties: 1936
Oct 2020–May 2021
8-Month 		17.84"
(453.14mm)		 19.13"
(485.90mm)		 -1.29"
(-32.76mm)		 26th Driest
Driest since:
 1934
102nd Wettest
Wettest since:
 2019
Sep 2020–May 2021
9-Month 		20.28"
(515.11mm)		 21.62"
(549.15mm)		 -1.34"
(-34.04mm)		 30th Driest
Driest since:
 1934
98th Wettest
Wettest since:
 2019
Aug 2020–May 2021
10-Month 		22.70"
(576.58mm)		 24.25"
(615.95mm)		 -1.55"
(-39.37mm)		 27th Driest
Driest since:
 1918
101st Wettest
Wettest since:
 2019
Jul 2020–May 2021
11-Month 		25.64"
(651.26mm)		 27.03"
(686.56mm)		 -1.39"
(-35.30mm)		 31st Driest
Driest since:
 1931
97th Wettest
Wettest since:
 2019
Jun 2020–May 2021
12-Month 		28.37"
(720.60mm)		 29.95"
(760.73mm)		 -1.58"
(-40.13mm)		 30th Driest
Driest since:
 1934
98th Wettest
Wettest since:
 2019
Ties: 1896
Dec 2019–May 2021
18-Month 		44.62"
(1,133.35mm)		 44.70"
(1,135.38mm)		 -0.08"
(-2.03mm)		 59th Driest
Driest since:
 1931
68th Wettest
Wettest since:
 2019
Jun 2019–May 2021
24-Month 		61.11"
(1,552.19mm)		 59.92"
(1,521.97mm)		 1.19"
(30.22mm)		 76th Driest
Driest since:
 1931
51st Wettest
Wettest since:
 2020
Jun 2018–May 2021
36-Month 		98.82"
(2,510.03mm)		 89.88"
(2,282.95mm)		 8.94"
(227.08mm)		 119th Driest
Driest since:
 1955
7th Wettest
Wettest since:
 2019
Jun 2017–May 2021
48-Month 		128.89"
(3,273.81mm)		 119.78"
(3,042.41mm)		 9.11"
(231.40mm)		 113th Driest
Driest since:
 1956
12th Wettest
Wettest since:
 2019
Jun 2016–May 2021
60-Month 		162.29"
(4,122.17mm)		 149.64"
(3,800.86mm)		 12.65"
(321.31mm)		 118th Driest
Driest since:
 1957
6th Wettest
Wettest since:
 2020

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