Temperature Breakdown by Decade

Detroit Area Average Monthly Temperatures from 1920 to 1940
Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Avg for Year
1920	16.9	22.7	37.7	41.0	56.5	69.1	69.7	69.5	65.7	59.5	39.1	32.8	48.4
1921	30.5	30.4	42.5	53.2	61.7	71.4	79.0	70.5	69.5	52.5	38.9	30.7	52.6
1922	23.8	28.5	36.9	48.1	62.9	69.3	72.7	70.9	67.1	54.7	42.7	29.2	50.6
1923	27.0	21.6	31.6	45.2	55.7	71.3	72.7	69.3	64.0	51.9	40.4	37.7	49.0
1924	21.8	25.5	33.7	46.0	52.2	65.6	69.9	70.7	59.4	57.4	39.8	23.2	47.1
1925	22.5	30.8	37.3	51.4	54.7	70.6	71.0	72.1	66.1	44.5	38.1	27.0	48.8
1926	25.4	25.8	29.0	41.0	57.9	63.4	72.4	72.0	62.9	50.6	38.2	25.9	47.0
1927	24.4	31.9	40.0	46.2	56.4	63.6	71.6	66.7	67.2	56.7	43.5	30.5	49.9
1928	26.4	27.0	33.7	43.7	58.3	63.4	73.6	73.2	60.8	55.4	42.5	32.9	49.2
1929	21.8	23.2	41.7	49.8	56.3	65.9	73.2	69.0	64.9	51.5	36.9	27.1	48.4
1930	22.9	33.8	34.4	47.6	61.0	70.5	74.7	73.5	66.3	51.6	42.0	29.6	50.7
1931	28.4	32.9	34.1	48.6	58.4	69.6	77.6	73.3	69.8	57.5	47.9	37.2	53.0
1932	36.7	33.0	29.8	44.3	59.7	70.3	73.0	73.7	64.9	52.9	37.2	29.5	50.4
1933	34.7	27.4	34.0	47.3	60.3	74.6	75.4	72.0	68.5	52.2	36.0	29.8	51.0
1934	30.0	14.8	29.3	44.1	61.6	73.2	75.6	69.2	66.4	52.2	43.6	26.0	48.8
1935	24.8	24.4	39.2	44.4	52.6	64.6	76.2	71.6	61.9	51.4	39.9	25.0	48.0
1936	21.7	16.1	37.6	42.3	62.8	65.9	74.7	73.1	66.3	51.2	35.4	32.2	48.3
1937	29.7	28.2	31.0	44.8	57.9	67.1	72.9	74.0	61.9	48.8	38.5	26.4	48.4
1938	24.3	31.2	41.6	48.2	58.5	67.6	74.0	74.9	61.8	55.1	42.7	30.3	50.9
1939	27.8	26.9	33.5	44.2	61.4	70.2	73.4	73.1	65.9	52.9	38.9	33.5	50.1
1940	19.0	26.7	28.7	42.8	55.7	67.6	73.4	70.5	62.8	52.2	38.0	32.1	47.5