Record envelope, standing records and threshold days for Monroe (USC00135638), Iowa, United States, with 38 years of record.
Key Facts for Monroe
Monroe (USC00135638) is a weather station in Iowa, United States at 41.52 latitude and -93.10 longitude, 281 m (922 ft) above sea level.
The station reports from 1911 to 1948, 38 years of record.
1,464 records set at Monroe still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
Monroe set a daily record low minimum temperature of -5.6 C (21.9 F) on 18 October 1948.
About the Station
Location: Iowa, United States, 41.52 latitude, -93.10 longitude.
Elevation: 281 m (922 ft).
Period of record: 1911 to 1948, 38 years.
Eligible elements: tmax, tmin, prcp, snow.
Daily Record Envelope and 2026
0 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Monroe. 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 Monroe, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
16.7 C (62.1 F)
-35.6 C (-32.1 F)
n/a
n/a
Feb
25.0 C (77.0 F)
-30.6 C (-23.1 F)
n/a
n/a
Mar
30.6 C (87.1 F)
-27.8 C (-18.0 F)
n/a
n/a
Apr
33.9 C (93.0 F)
-13.3 C (8.1 F)
n/a
n/a
May
40.6 C (105.1 F)
-3.3 C (26.1 F)
n/a
n/a
Jun
40.0 C (104.0 F)
2.8 C (37.0 F)
n/a
n/a
Jul
43.3 C (109.9 F)
6.7 C (44.1 F)
n/a
n/a
Aug
43.3 C (109.9 F)
3.3 C (37.9 F)
n/a
n/a
Sep
40.0 C (104.0 F)
-4.4 C (24.1 F)
n/a
n/a
Oct
35.0 C (95.0 F)
-15.6 C (3.9 F)
n/a
n/a
Nov
33.3 C (91.9 F)
-21.1 C (-6.0 F)
n/a
n/a
Dec
21.7 C (71.1 F)
-31.7 C (-25.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Monroe still stand. 1936 holds the most, with 80.
Standing records at Monroe by the year they were set
Year set
Standing records
1911
7
1912
54
1913
48
1914
41
1915
47
1916
38
1917
45
1918
55
1919
23
1920
40
1921
49
1922
18
1923
30
1924
34
1925
49
1926
36
1927
47
1928
36
1929
29
1930
61
1931
41
1932
28
1933
38
1934
71
1935
29
1936
80
1937
34
1938
37
1939
31
1940
41
1941
24
1942
44
1943
30
1944
25
1945
29
1946
34
1947
41
1948
20
Wettest Day of Each Month
Jun: 136.4 mm (5.4 in)
The wettest day on record for each calendar month at Monroe. The most was 136.4 mm (5.4 in) on 24 June 1918.
Record daily precipitation for each month at Monroe
Month
Record daily precipitation (mm)
Date
Jan
40.1 mm (1.6 in)
5 January 1946
Feb
60.7 mm (2.4 in)
23 February 1915
Mar
52.3 mm (2.1 in)
30 March 1938
Apr
70.4 mm (2.8 in)
6 April 1938
May
70.1 mm (2.8 in)
13 May 1916
Jun
136.4 mm (5.4 in)
24 June 1918
Jul
87.9 mm (3.5 in)
6 July 1925
Aug
71.4 mm (2.8 in)
30 August 1948
Sep
100.6 mm (4.0 in)
14 September 1914
Oct
64.0 mm (2.5 in)
7 October 1914
Nov
81.5 mm (3.2 in)
23 November 1931
Dec
34.8 mm (1.4 in)
23 December 1941
Period of Record Coverage
1911 to 1948
Complete yearUnder 90 percent of days
38 years of record at Monroe, 1911 to 1948. 3 years have data for under 90 percent of days and are left out of rankings: 1911, 1946, 1948.
Cooler than the station meanWarmer than the station mean
One stripe for each of 32 complete years at Monroe, 1912 to 1947. Blue stripes are years cooler than the station's own mean of 10.3 C (50.6 F); red stripes are warmer. The coolest year was 1917, at 8.3 C (46.9 F), and the warmest was 1921, at 12.7 C (54.8 F). The strongest colour marks a difference of 2.4 C (4.3 F).
Annual mean temperature at Monroe as warming stripes, 1912 to 1947
Year
Annual mean temperature
Difference from the station mean
1912
8.7 C
-1.65 C
1913
10.6 C
+0.30 C
1914
10.0 C
-0.34 C
1915
9.4 C
-0.94 C
1916
9.4 C
-0.93 C
1917
8.3 C
-2.07 C
1918
10.5 C
+0.18 C
1919
10.0 C
-0.36 C
1920
10.4 C
+0.04 C
1921
12.7 C
+2.33 C
1922
11.5 C
+1.20 C
1923
10.8 C
+0.43 C
1925
10.2 C
-0.09 C
1926
10.5 C
+0.20 C
1929
8.8 C
-1.53 C
1930
10.9 C
+0.60 C
1931
12.4 C
+2.10 C
1932
9.9 C
-0.42 C
1933
11.5 C
+1.15 C
1934
11.8 C
+1.48 C
1935
9.7 C
-0.58 C
1936
9.9 C
-0.38 C
1937
9.3 C
-1.02 C
1938
11.7 C
+1.35 C
1939
11.3 C
+0.96 C
1940
9.1 C
-1.27 C
1941
11.0 C
+0.63 C
1942
10.1 C
-0.27 C
1943
9.3 C
-0.98 C
1944
10.5 C
+0.22 C
1945
9.7 C
-0.64 C
1947
10.6 C
+0.29 C
The fitted trend in annual mean temperature here over 1912 to 1947 is 0.1 C (-0.2 to 0.5) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.2 F (-0.4 to 0.9) per decade. The slope is a straight line fitted to 32 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Monroe
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.1 C (-0.2 to 0.5) per decade
0.2 F (-0.4 to 0.9) per decade
1912 to 1947
32
Not clearly different from zero
Mean daily maximum
0.2 C (-0.2 to 0.6) per decade
0.4 F (-0.4 to 1.1) per decade
1912 to 1947
32
Not clearly different from zero
Mean daily minimum
0.1 C (-0.3 to 0.4) per decade
0.1 F (-0.5 to 0.8) per decade
1912 to 1947
32
Not clearly different from zero
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1911 to 1948
Yearly extremes at Monroe: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
43.3 C (109.9 F)
1934
38.3 C (100.9 F)
38
Coldest night (TNn)
-35.6 C (-32.1 F)
1912
-25.8 C (-14.5 F)
38
Wettest day (Rx1day)
136.4 mm (5.4 in)
1918
63.8 mm (2.5 in)
38
Wettest five days (Rx5day)
171.5 mm (6.8 in)
1914
99.0 mm (3.9 in)
38
Longest dry spell (CDD)
40 days
1914
24 days
38
Hottest day (TXx)
The hottest day of the year at Monroe, 1911 to 1948. The record is 43.3 C (109.9 F) in 1934, marked on the chart; the median year is 38.3 C (100.9 F).
Hottest day (TXx) at Monroe by year
Year
Hottest day (TXx)
1911
40.6 C (105.1 F)
1912
37.2 C (99.0 F)
1913
40.0 C (104.0 F)
1914
39.4 C (102.9 F)
1915
33.9 C (93.0 F)
1916
38.9 C (102.0 F)
1917
38.9 C (102.0 F)
1918
42.8 C (109.0 F)
1919
37.8 C (100.0 F)
1920
36.7 C (98.1 F)
1921
37.8 C (100.0 F)
1922
36.7 C (98.1 F)
1923
36.1 C (97.0 F)
1924
37.8 C (100.0 F)
1925
40.6 C (105.1 F)
1926
39.4 C (102.9 F)
1927
37.2 C (99.0 F)
1928
35.0 C (95.0 F)
1929
34.4 C (93.9 F)
1930
41.1 C (106.0 F)
1931
40.0 C (104.0 F)
1932
35.6 C (96.1 F)
1933
39.4 C (102.9 F)
1934
43.3 C (109.9 F)
1935
37.2 C (99.0 F)
1936
43.3 C (109.9 F)
1937
37.8 C (100.0 F)
1938
38.3 C (100.9 F)
1939
38.9 C (102.0 F)
1940
39.4 C (102.9 F)
1941
38.3 C (100.9 F)
1942
35.0 C (95.0 F)
1943
35.0 C (95.0 F)
1944
37.8 C (100.0 F)
1945
38.9 C (102.0 F)
1946
36.7 C (98.1 F)
1947
42.8 C (109.0 F)
1948
40.0 C (104.0 F)
Coldest night (TNn)
The coldest night of the year at Monroe, 1911 to 1948. The record is -35.6 C (-32.1 F) in 1912, marked on the chart; the median year is -25.8 C (-14.5 F).
Coldest night (TNn) at Monroe by year
Year
Coldest night (TNn)
1911
-22.8 C (-9.0 F)
1912
-35.6 C (-32.1 F)
1913
-26.1 C (-15.0 F)
1914
-29.4 C (-20.9 F)
1915
-31.1 C (-24.0 F)
1916
-31.1 C (-24.0 F)
1917
-30.6 C (-23.1 F)
1918
-30.6 C (-23.1 F)
1919
-30.6 C (-23.1 F)
1920
-23.9 C (-11.0 F)
1921
-21.7 C (-7.1 F)
1922
-22.8 C (-9.0 F)
1923
-24.4 C (-11.9 F)
1924
-32.2 C (-26.0 F)
1925
-25.0 C (-13.0 F)
1926
-23.3 C (-9.9 F)
1927
-25.0 C (-13.0 F)
1928
-23.3 C (-9.9 F)
1929
-27.8 C (-18.0 F)
1930
-32.2 C (-26.0 F)
1931
-19.4 C (-2.9 F)
1932
-28.3 C (-18.9 F)
1933
-30.6 C (-23.1 F)
1934
-23.9 C (-11.0 F)
1935
-25.0 C (-13.0 F)
1936
-30.6 C (-23.1 F)
1937
-22.2 C (-8.0 F)
1938
-23.3 C (-9.9 F)
1939
-23.3 C (-9.9 F)
1940
-30.6 C (-23.1 F)
1941
-21.1 C (-6.0 F)
1942
-30.0 C (-22.0 F)
1943
-29.4 C (-20.9 F)
1944
-26.7 C (-16.1 F)
1945
-23.9 C (-11.0 F)
1946
-23.9 C (-11.0 F)
1947
-28.3 C (-18.9 F)
1948
-25.6 C (-14.1 F)
Wettest day (Rx1day)
The wettest day of the year at Monroe, 1911 to 1948. The record is 136.4 mm (5.4 in) in 1918, marked on the chart; the median year is 63.8 mm (2.5 in).
Wettest day (Rx1day) at Monroe by year
Year
Wettest day (Rx1day)
1911
97.3 mm (3.8 in)
1912
54.6 mm (2.1 in)
1913
45.7 mm (1.8 in)
1914
100.6 mm (4.0 in)
1915
70.6 mm (2.8 in)
1916
70.1 mm (2.8 in)
1917
50.5 mm (2.0 in)
1918
136.4 mm (5.4 in)
1919
54.9 mm (2.2 in)
1920
50.3 mm (2.0 in)
1921
68.1 mm (2.7 in)
1922
68.3 mm (2.7 in)
1923
68.8 mm (2.7 in)
1924
51.3 mm (2.0 in)
1925
87.9 mm (3.5 in)
1926
65.5 mm (2.6 in)
1927
38.1 mm (1.5 in)
1928
61.2 mm (2.4 in)
1929
36.1 mm (1.4 in)
1930
65.0 mm (2.6 in)
1931
81.5 mm (3.2 in)
1932
64.3 mm (2.5 in)
1933
49.8 mm (2.0 in)
1934
35.8 mm (1.4 in)
1935
49.0 mm (1.9 in)
1936
61.2 mm (2.4 in)
1937
42.7 mm (1.7 in)
1938
70.4 mm (2.8 in)
1939
56.1 mm (2.2 in)
1940
46.7 mm (1.8 in)
1941
77.2 mm (3.0 in)
1942
42.2 mm (1.7 in)
1943
63.2 mm (2.5 in)
1944
69.6 mm (2.7 in)
1945
41.9 mm (1.6 in)
1946
70.9 mm (2.8 in)
1947
77.7 mm (3.1 in)
1948
71.4 mm (2.8 in)
Wettest five days (Rx5day)
The wettest five days of the year at Monroe, 1911 to 1948. The record is 171.5 mm (6.8 in) in 1914, marked on the chart; the median year is 99.0 mm (3.9 in).
Wettest five days (Rx5day) at Monroe by year
Year
Wettest five days (Rx5day)
1911
119.9 mm (4.7 in)
1912
64.8 mm (2.6 in)
1913
94.0 mm (3.7 in)
1914
171.5 mm (6.8 in)
1915
118.0 mm (4.6 in)
1916
81.0 mm (3.2 in)
1917
138.1 mm (5.4 in)
1918
159.0 mm (6.3 in)
1919
124.2 mm (4.9 in)
1920
96.8 mm (3.8 in)
1921
120.9 mm (4.8 in)
1922
112.7 mm (4.4 in)
1923
105.4 mm (4.1 in)
1924
96.2 mm (3.8 in)
1925
94.2 mm (3.7 in)
1926
113.3 mm (4.5 in)
1927
102.4 mm (4.0 in)
1928
101.9 mm (4.0 in)
1929
77.3 mm (3.0 in)
1930
100.4 mm (4.0 in)
1931
122.6 mm (4.8 in)
1932
125.2 mm (4.9 in)
1933
63.0 mm (2.5 in)
1934
100.4 mm (4.0 in)
1935
76.4 mm (3.0 in)
1936
112.5 mm (4.4 in)
1937
62.8 mm (2.5 in)
1938
91.2 mm (3.6 in)
1939
85.1 mm (3.4 in)
1940
124.5 mm (4.9 in)
1941
92.0 mm (3.6 in)
1942
71.1 mm (2.8 in)
1943
95.0 mm (3.7 in)
1944
138.0 mm (5.4 in)
1945
74.9 mm (2.9 in)
1946
52.5 mm (2.1 in)
1947
97.6 mm (3.8 in)
1948
89.4 mm (3.5 in)
Longest dry spell (CDD)
The longest dry spell of the year at Monroe, 1911 to 1948. The record is 40 days in 1914, marked on the chart; the median year is 24 days.
Longest dry spell (CDD) at Monroe by year
Year
Longest dry spell (CDD)
1911
22 days
1912
25 days
1913
30 days
1914
40 days
1915
21 days
1916
35 days
1917
34 days
1918
31 days
1919
31 days
1920
17 days
1921
21 days
1922
20 days
1923
25 days
1924
20 days
1925
22 days
1926
20 days
1927
23 days
1928
23 days
1929
14 days
1930
19 days
1931
26 days
1932
23 days
1933
22 days
1934
35 days
1935
19 days
1936
22 days
1937
29 days
1938
24 days
1939
24 days
1940
21 days
1941
18 days
1942
33 days
1943
26 days
1944
25 days
1945
33 days
1946
25 days
1947
26 days
1948
32 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.
Frost Dates and Growing Season
32 years with a frost
Across 32 years with a frost, the median last spring frost at Monroe falls on 27 April and the median first autumn frost on 12 October, which leaves a median of 168 days between them.
Fitted over all years, the growing season changes by +0.6 days per decade at this station.
Frost dates and growing season at Monroe
Measure
Median, all years
Earliest period
Recent period (1914 to 1947)
Recent against earliest
Fitted trend
Last spring frost
27 April
n/a
28 April
n/a
+2.1 days per decade
First autumn frost
12 October
n/a
12 October
n/a
+2.7 days per decade
Growing days
168 days
n/a
168 days
n/a
+0.6 days per decade
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
33 years, 1912 to 1945
A day with at least 58.6 mm (2.3 in) of rain is expected about once in 2 years. A day with at least 127.3 mm (5.0 in) of rain is expected about once in 100 years.
Rainfall return levels at Monroe: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
58.6 mm (2.3 in)
5 years
75.3 mm (3.0 in)
10 years
87.1 mm (3.4 in)
25 years
102.6 mm (4.0 in)
50 years
114.8 mm (4.5 in)
Longer than the 33 years of record
100 years
127.3 mm (5.0 in)
Longer than the 33 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, 33 years of values from 1912 to 1945.
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: 136.4 mm (5.4 in) in 1918; 100.6 mm (4.0 in) in 1914; 87.9 mm (3.5 in) in 1925.
Download the Data
Data for Monroe standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Monroe 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.