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Decatur May Weather

Averages and records for weather in Decatur, Illinois in the month of May.

Typical Decatur May Weather 1991–2020
Average daily high	75.0 °F
Average daily low	53.5 °F
Average monthly precipitation	4.9 inches
Average monthly snow	none
Daily chance of precipitation	43.0%
Daily chance of snow	0%

Decatur May Weather Records 1893–2024
Highest temperature	101 °F	May 31, 1934
Lowest temperature	25 °F	May 14, 1895
Highest daily low	75 °F	May 25, 2000
Lowest daily high	38 °F	May 2, 1909
Hottest average high temperature	85.1 °F	1987
Coldest average high temperature	68.2 °F	1946
Most daily precipitation	4.2 inches	May 19, 1974
Most monthly precipitation	12.6 inches	1943
Most daily snow	4.0 inches	May 2, 1929
Most monthly snow	4.0 inches	1929

Note: Daily averages are a moving average which includes 14 days before and after

Day	Average (°F)		Record (°F)
Day	High	Low	High	Low
May 1	70.0	48.6	92	26
May 2	70.2	48.9	91	30
May 3	70.4	49.2	94	30
May 4	70.7	49.4	92	31
May 5	71.0	49.6	94	32
May 6	71.3	50.0	91	28
May 7	71.6	50.3	90	27
May 8	72.0	50.6	94	33
May 9	72.5	51.0	97	29
May 10	72.9	51.3	94	27
May 11	73.1	51.7	95	31
May 12	73.5	52.1	92	30
May 13	73.9	52.5	91	32
May 14	74.4	52.9	93	25
May 15	74.7	53.3	94	35
May 16	75.1	53.6	92	33
May 17	75.5	53.9	92	35
May 18	75.9	54.2	93	34
May 19	76.2	54.6	93	33
May 20	76.4	54.9	95	34
May 21	76.6	55.3	96	31
May 22	76.8	55.5	97	33
May 23	77.0	55.7	96	35
May 24	77.3	56.0	96	38
May 25	77.6	56.3	95	29
May 26	77.9	56.6	94	31
May 27	78.3	57.0	96	34
May 28	78.7	57.4	96	36
May 29	79.1	57.9	96	36
May 30	79.5	58.2	98	36
May 31	79.8	58.6	101	35

Weather Station Details

Years	Station	Coordinates
1893–2024	Decatur WTP	location