Potomac Fltr Plt Weather Records (USC00187272)

Record envelope, standing records and threshold days for Potomac Fltr Plt (USC00187272), Maryland, United States, with 50 years of record.

Key Facts for Potomac Fltr Plt

Potomac Fltr Plt (USC00187272) is a weather station in Maryland, United States at 39.04 latitude and -77.25 longitude, 82 m (270 ft) above sea level.
The station reports from 1962 to 2011, 50 years of record.
732 records set at Potomac Fltr Plt still stand.
Records are tracked for prcp, snow, snwd: an element needs 30 years of data to be eligible.
Potomac Fltr Plt set a daily record precipitation of 66.8 mm (2.6 in) on 30 September 2010.

About the Station

Location: Maryland, United States, 39.04 latitude, -77.25 longitude.
Elevation: 82 m (270 ft).
Period of record: 1962 to 2011, 50 years.
Eligible elements: prcp, snow, snwd.

Daily Record Envelope and 2026

0 days at or beyond a record

The band shows the record high and record low for each calendar day at Potomac Fltr Plt. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.

Daily record high and record low at Potomac Fltr Plt, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	24.4 C (75.9 F)	-15.6 C (3.9 F)	n/a	n/a
Feb	n/a	n/a	n/a	n/a
Mar	25.6 C (78.1 F)	-6.7 C (19.9 F)	n/a	n/a
Apr	25.0 C (77.0 F)	-1.1 C (30.0 F)	n/a	n/a
May	30.0 C (86.0 F)	-1.1 C (30.0 F)	n/a	n/a
Jun	n/a	n/a	n/a	n/a
Jul	35.6 C (96.1 F)	13.3 C (55.9 F)	n/a	n/a
Aug	n/a	n/a	n/a	n/a
Sep	n/a	n/a	n/a	n/a
Oct	28.9 C (84.0 F)	6.7 C (44.1 F)	n/a	n/a
Nov	n/a	n/a	n/a	n/a
Dec	18.9 C (66.0 F)	-8.9 C (16.0 F)	n/a	n/a

Which Years Hold Standing Records

732 standing records

732 records at Potomac Fltr Plt still stand. 1972 holds the most, with 242.

Wettest Day of Each Month

Jun: 202.2 mm (8.0 in)

The wettest day on record for each calendar month at Potomac Fltr Plt. The most was 202.2 mm (8.0 in) on 22 June 1972.

Record daily precipitation for each month at Potomac Fltr Plt
Month	Record daily precipitation (mm)	Date
Jan	52.3 mm (2.1 in)	7 January 1996
Feb	50.8 mm (2.0 in)	4 February 1998
Mar	57.2 mm (2.3 in)	4 March 1993
Apr	71.1 mm (2.8 in)	20 April 2008
May	73.7 mm (2.9 in)	26 May 2009
Jun	202.2 mm (8.0 in)	22 June 1972
Jul	91.4 mm (3.6 in)	15 July 2005
Aug	96.5 mm (3.8 in)	21 August 1963
Sep	173.2 mm (6.8 in)	6 September 2008
Oct	94.0 mm (3.7 in)	23 October 1990
Nov	76.2 mm (3.0 in)	25 November 1971
Dec	65.0 mm (2.6 in)	1 December 1974

Period of Record Coverage

1967 to 1979

6 years of record at Potomac Fltr Plt, 1967 to 1979. 6 years have data for under 90 percent of days and are left out of rankings: 1967, 1968, 1970, 1971, 1972, 1979.

Latest Records

Latest records at Potomac Fltr Plt
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
30 September 2010	Potomac Fltr Plt, US	daily rain	66.8 mm (2.6 in)	42.9 mm (1.7 in)	11 years	29 of 100 (Routine)
17 May 2010	Potomac Fltr Plt, US	daily rain	21.3 mm (0.8 in)	2.0 mm (0.08 in)	24 years	12 of 100 (Routine)
24 October 2009	Potomac Fltr Plt, US	daily rain	38.1 mm (1.5 in)	22.9 mm (0.9 in)	2 years	21 of 100 (Routine)
17 October 2009	Potomac Fltr Plt, US	daily rain	27.7 mm (1.1 in)	3.3 mm (0.13 in)	34 years	16 of 100 (Routine)
15 October 2009	Potomac Fltr Plt, US	daily rain	15.5 mm (0.6 in)	5.3 mm (0.21 in)	12 years	10 of 100 (Routine)
22 August 2009	Potomac Fltr Plt, US	daily rain	23.1 mm (0.9 in)	8.4 mm (0.33 in)	44 years	20 of 100 (Routine)
18 June 2009	Potomac Fltr Plt, US	daily rain	46.7 mm (1.8 in)	3.5 mm (0.14 in)	12 years	9 of 100 (Routine)
10 June 2009	Potomac Fltr Plt, US	daily rain	35.8 mm (1.4 in)	23.1 mm (0.9 in)	28 years	25 of 100 (Routine)
26 May 2009	Potomac Fltr Plt, US	monthly rain	73.7 mm (2.9 in)	8.7 mm (0.34 in)	20 years	28 of 100 (Routine)
6 September 2008	Potomac Fltr Plt, US	monthly rain	173.2 mm (6.8 in)	41.1 mm (1.6 in)	41 years	49 of 100 (Notable)
29 August 2008	Potomac Fltr Plt, US	daily rain	29.0 mm (1.1 in)	15.8 mm (0.6 in)	20 years	20 of 100 (Routine)
12 May 2008	Potomac Fltr Plt, US	daily rain	37.3 mm (1.5 in)	5.3 mm (0.21 in)	34 years	19 of 100 (Routine)
11 May 2008	Potomac Fltr Plt, US	daily rain	50.8 mm (2.0 in)	22.6 mm (0.9 in)	2 years	26 of 100 (Routine)
9 May 2008	Potomac Fltr Plt, US	daily rain	38.1 mm (1.5 in)	17.5 mm (0.7 in)	34 years	31 of 100 (Routine)
20 April 2008	Potomac Fltr Plt, US	monthly rain	71.1 mm (2.8 in)	0.2 mm (0.01 in)	8 years	16 of 100 (Routine)
3 April 2008	Potomac Fltr Plt, US	daily rain	20.1 mm (0.8 in)	8.4 mm (0.33 in)	44 years	20 of 100 (Routine)
13 February 2008	Potomac Fltr Plt, US	daily rain	29.2 mm (1.1 in)	11.4 mm (0.4 in)	36 years	25 of 100 (Routine)
1 February 2008	Potomac Fltr Plt, US	daily rain	44.5 mm (1.8 in)	22.9 mm (0.9 in)	22 years	33 of 100 (Routine)
24 October 2007	Potomac Fltr Plt, US	daily rain	15.2 mm (0.6 in)	0.2 mm (0.01 in)	36 years	14 of 100 (Routine)
15 April 2007	Potomac Fltr Plt, US	daily rain	58.9 mm (2.3 in)	1.7 mm (0.07 in)	24 years	12 of 100 (Routine)

Extremes by Year

1962 to 2011

Yearly extremes at Potomac Fltr Plt: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	35.6 C (96.1 F)	1972	25.0 C (77.0 F)	6
Coldest night (TNn)	-15.6 C (3.9 F)	1971	-8.3 C (17.0 F)	6
Wettest day (Rx1day)	202.2 mm (8.0 in)	1972	65.0 mm (2.6 in)	50
Wettest five days (Rx5day)	265.5 mm (10.5 in)	1972	90.5 mm (3.6 in)	50
Longest dry spell (CDD)	38 days	1967	20 days	50

Hottest day (TXx)

The hottest day of the year at Potomac Fltr Plt, 1962 to 2011. The record is 35.6 C (96.1 F) in 1972, marked on the chart; the median year is 25.0 C (77.0 F).

Hottest day (TXx) at Potomac Fltr Plt by year
Year	Hottest day (TXx)
1962	n/a
1963	n/a
1964	n/a
1965	n/a
1966	n/a
1967	24.4 C (75.9 F)
1968	28.9 C (84.0 F)
1969	n/a
1970	20.0 C (68.0 F)
1971	21.1 C (70.0 F)
1972	35.6 C (96.1 F)
1973	n/a
1974	n/a
1975	n/a
1976	n/a
1977	n/a
1978	n/a
1979	25.6 C (78.1 F)
1980	n/a
1981	n/a
1982	n/a
1983	n/a
1984	n/a
1985	n/a
1986	n/a
1987	n/a
1988	n/a
1989	n/a
1990	n/a
1991	n/a
1992	n/a
1993	n/a
1994	n/a
1995	n/a
1996	n/a
1997	n/a
1998	n/a
1999	n/a
2000	n/a
2001	n/a
2002	n/a
2003	n/a
2004	n/a
2005	n/a
2006	n/a
2007	n/a
2008	n/a
2009	n/a
2010	n/a
2011	n/a

Coldest night (TNn)

The coldest night of the year at Potomac Fltr Plt, 1962 to 2011. The record is -15.6 C (3.9 F) in 1971, marked on the chart; the median year is -8.3 C (17.0 F).

Coldest night (TNn) at Potomac Fltr Plt by year
Year	Coldest night (TNn)
1962	n/a
1963	n/a
1964	n/a
1965	n/a
1966	n/a
1967	-13.9 C (7.0 F)
1968	-1.1 C (30.0 F)
1969	n/a
1970	-8.9 C (16.0 F)
1971	-15.6 C (3.9 F)
1972	-7.8 C (18.0 F)
1973	n/a
1974	n/a
1975	n/a
1976	n/a
1977	n/a
1978	n/a
1979	-5.6 C (21.9 F)
1980	n/a
1981	n/a
1982	n/a
1983	n/a
1984	n/a
1985	n/a
1986	n/a
1987	n/a
1988	n/a
1989	n/a
1990	n/a
1991	n/a
1992	n/a
1993	n/a
1994	n/a
1995	n/a
1996	n/a
1997	n/a
1998	n/a
1999	n/a
2000	n/a
2001	n/a
2002	n/a
2003	n/a
2004	n/a
2005	n/a
2006	n/a
2007	n/a
2008	n/a
2009	n/a
2010	n/a
2011	n/a

Wettest day (Rx1day)

The wettest day of the year at Potomac Fltr Plt, 1962 to 2011. The record is 202.2 mm (8.0 in) in 1972, marked on the chart; the median year is 65.0 mm (2.6 in).

Wettest day (Rx1day) at Potomac Fltr Plt by year
Year	Wettest day (Rx1day)
1962	52.8 mm (2.1 in)
1963	96.5 mm (3.8 in)
1964	57.7 mm (2.3 in)
1965	57.9 mm (2.3 in)
1966	132.1 mm (5.2 in)
1967	84.3 mm (3.3 in)
1968	107.2 mm (4.2 in)
1969	71.6 mm (2.8 in)
1970	36.8 mm (1.4 in)
1971	76.2 mm (3.0 in)
1972	202.2 mm (8.0 in)
1973	81.3 mm (3.2 in)
1974	65.0 mm (2.6 in)
1975	57.2 mm (2.3 in)
1976	55.9 mm (2.2 in)
1977	59.9 mm (2.4 in)
1978	50.8 mm (2.0 in)
1979	116.8 mm (4.6 in)
1980	48.0 mm (1.9 in)
1981	37.3 mm (1.5 in)
1982	73.7 mm (2.9 in)
1983	62.5 mm (2.5 in)
1984	54.6 mm (2.1 in)
1985	64.3 mm (2.5 in)
1986	52.1 mm (2.1 in)
1987	100.3 mm (3.9 in)
1988	45.7 mm (1.8 in)
1989	65.0 mm (2.6 in)
1990	94.0 mm (3.7 in)
1991	55.9 mm (2.2 in)
1992	46.2 mm (1.8 in)
1993	69.1 mm (2.7 in)
1994	91.2 mm (3.6 in)
1995	50.8 mm (2.0 in)
1996	68.6 mm (2.7 in)
1997	70.6 mm (2.8 in)
1998	50.8 mm (2.0 in)
1999	73.2 mm (2.9 in)
2000	70.9 mm (2.8 in)
2001	63.0 mm (2.5 in)
2002	48.5 mm (1.9 in)
2003	67.1 mm (2.6 in)
2004	51.3 mm (2.0 in)
2005	91.4 mm (3.6 in)
2006	167.4 mm (6.6 in)
2007	58.9 mm (2.3 in)
2008	173.2 mm (6.8 in)
2009	81.3 mm (3.2 in)
2010	66.8 mm (2.6 in)
2011	16.8 mm (0.7 in)

Wettest five days (Rx5day)

The wettest five days of the year at Potomac Fltr Plt, 1962 to 2011. The record is 265.5 mm (10.5 in) in 1972, marked on the chart; the median year is 90.5 mm (3.6 in).

Wettest five days (Rx5day) at Potomac Fltr Plt by year
Year	Wettest five days (Rx5day)
1962	58.1 mm (2.3 in)
1963	121.9 mm (4.8 in)
1964	65.0 mm (2.6 in)
1965	66.5 mm (2.6 in)
1966	196.9 mm (7.8 in)
1967	132.8 mm (5.2 in)
1968	110.2 mm (4.3 in)
1969	79.8 mm (3.1 in)
1970	60.2 mm (2.4 in)
1971	86.1 mm (3.4 in)
1972	265.5 mm (10.5 in)
1973	82.8 mm (3.3 in)
1974	75.9 mm (3.0 in)
1975	157.6 mm (6.2 in)
1976	84.6 mm (3.3 in)
1977	87.3 mm (3.4 in)
1978	90.2 mm (3.6 in)
1979	142.8 mm (5.6 in)
1980	72.7 mm (2.9 in)
1981	61.7 mm (2.4 in)
1982	83.3 mm (3.3 in)
1983	93.1 mm (3.7 in)
1984	96.3 mm (3.8 in)
1985	77.5 mm (3.1 in)
1986	57.4 mm (2.3 in)
1987	121.9 mm (4.8 in)
1988	106.4 mm (4.2 in)
1989	94.0 mm (3.7 in)
1990	96.5 mm (3.8 in)
1991	60.0 mm (2.4 in)
1992	72.4 mm (2.9 in)
1993	110.5 mm (4.4 in)
1994	107.0 mm (4.2 in)
1995	59.2 mm (2.3 in)
1996	102.4 mm (4.0 in)
1997	68.8 mm (2.7 in)
1998	90.8 mm (3.6 in)
1999	91.0 mm (3.6 in)
2000	107.0 mm (4.2 in)
2001	97.5 mm (3.8 in)
2002	70.6 mm (2.8 in)
2003	83.9 mm (3.3 in)
2004	66.9 mm (2.6 in)
2005	138.2 mm (5.4 in)
2006	240.3 mm (9.5 in)
2007	83.5 mm (3.3 in)
2008	135.1 mm (5.3 in)
2009	107.4 mm (4.2 in)
2010	140.7 mm (5.5 in)
2011	5.8 mm (0.23 in)

Longest dry spell (CDD)

The longest dry spell of the year at Potomac Fltr Plt, 1962 to 2011. The record is 38 days in 1967, marked on the chart; the median year is 20 days.

Longest dry spell (CDD) at Potomac Fltr Plt by year
Year	Longest dry spell (CDD)
1962	24 days
1963	31 days
1964	29 days
1965	18 days
1966	21 days
1967	38 days
1968	26 days
1969	30 days
1970	19 days
1971	21 days
1972	13 days
1973	26 days
1974	19 days
1975	13 days
1976	18 days
1977	30 days
1978	19 days
1979	16 days
1980	14 days
1981	18 days
1982	16 days
1983	15 days
1984	23 days
1985	24 days
1986	21 days
1987	23 days
1988	21 days
1989	18 days
1990	18 days
1991	23 days
1992	18 days
1993	20 days
1994	16 days
1995	33 days
1996	17 days
1997	13 days
1998	32 days
1999	23 days
2000	30 days
2001	37 days
2002	16 days
2003	22 days
2004	17 days
2005	16 days
2006	31 days
2007	20 days
2008	16 days
2009	16 days
2010	18 days
2011	10 days

Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.

Rainfall Return Levels

41 years, 1963 to 2010

A day with at least 64.0 mm (2.5 in) of rain is expected about once in 2 years. A day with at least 192.3 mm (7.6 in) of rain is expected about once in 100 years.

Rainfall return levels at Potomac Fltr Plt: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	64.0 mm (2.5 in)
5 years	85.4 mm (3.4 in)
10 years	103.7 mm (4.1 in)
25 years	132.8 mm (5.2 in)
50 years	159.8 mm (6.3 in)	Longer than the 41 years of record
100 years	192.3 mm (7.6 in)	Longer than the 41 years of record

The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 41 years of values from 1963 to 2010.

A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.

The largest wettest-day totals in the fit: 202.2 mm (8.0 in) in 1972; 132.1 mm (5.2 in) in 1966; 116.8 mm (4.6 in) in 1979.

Download the Data

Data for Potomac Fltr Plt standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Potomac Fltr Plt threshold days by year: CSV or JSON. Field meanings are on the data page.

Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-15 (15 October 2026). Records are computed by this site and are not official.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).