Twin Cities Snowfall Event Count and Seasonal Snowfall Summary Statistics

The following tables and graphs were assembled to provide Twin Citians with historical climatological context upon which to base decisions related to snowfall. For example, a snow removal contractor and their customer might use the tables below to determine whether a seasonal flat-fee, or a per-visit charge is in the interest of both parties. Assuming that it is agreed that a two-inch snowfall is "plowable", the Days with Snowfall ... 2.0 inches and greater table below indicates that on average, a "plowable" snowfall occurs in the Twin Cities 7.4 days per season, with a standard deviation (a measure of variability) of 3.43 days. In tandem, these statistics inform users that during most seasons (two-thirds of all seasons), the metropolitan area receives two or more inches of snow between four and eleven times. The table also indicates that decision makers should account for the fact that the Twin Cities has had seasons with as many as 16 days of "plowable" snow, and as few as one day of "plowable" snow.

The data are comprised of a mosaic of 120 seasons of snow data gathered in downtown Minneapolis (1891-1938), the Twin Cities International Airport (1938-2000, 2004-2011), and the Chanhassen National Weather Service Forecast Office (2000 to 2004).

Number of Days with Snowfall of 0.1 inch (measureable) and greater (1891 through 2011)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Season
avg.	8.8	7.1	6.1	2.1	0.2	0.0	0.0	0.0	0.0	0.6	4.5	7.9	37.3
st dev	3.56	2.74	3.13	1.73	0.47	0.00	0.00	0.00	0.16	1.07	3.01	3.52	8.56
median	9.0	7.0	6.0	2.0	0.0	0.0	0.0	0.0	0.0	0.0	4.0	7.0	36.5
90%	13.0	11.0	10.0	5.0	1.0	0.0	0.0	0.0	0.0	2.0	9.0	13.0	50.0
10%	4.0	4.0	2.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0	4.0	26.0
max	19.0	14.0	15.0	7.0	2.0	0.0	0.0	0.0	1.0	6.0	14.0	18.0	54.0
min	1.0	2.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	19.0

Number of Days with Snowfall of 1.0 inch and greater (1891 through 2011)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Season
avg.	3.3	2.6	2.7	0.8	0.1	0.0	0.0	0.0	0.0	0.2	1.8	2.9	14.4
st dev	2.29	1.75	2.01	1.04	0.23	0.00	0.00	0.00	0.09	0.44	1.79	2.29	5.27
median	3.0	2.0	2.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0	3.0	14.0
90%	6.0	5.0	6.0	2.0	0.0	0.0	0.0	0.0	0.0	1.0	4.0	6.0	22.0
10%	1.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	8.0
max	12	8	9	4	1	0	0	0	1	2	8	11	27
min	0	0	0	0	0	0	0	0	0	0	0	0	3

Number of Days with Snowfall of 2.0 inches and greater (1891 through 2011)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Season
avg.	1.6	1.4	1.6	0.5	0.0	0.0	0.0	0.0	0.0	0.1	0.9	1.4	7.4
st dev	1.36	1.24	1.41	0.78	0.20	0.00	0.00	0.00	0.00	0.28	1.23	1.41	3.44
median	1.0	1.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0	1.0	7.0
90%	3.0	3.0	3.0	2.0	0.0	0.0	0.0	0.0	0.0	0.0	3.0	3.1	12.0
10%	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	3.0
max	6.0	5.0	7.0	4.0	1.0	0.0	0.0	0.0	0.0	1.0	5.0	6.0	16.0
min	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0
Seasonal Snow Totals Time Series
click on time-trend graphic to enlarge

Number of Days with Snowfall of 4.0 inches and greater (1891 through 2011)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Season
avg.	0.5	0.4	0.6	0.2	0.0	0.0	0.0	0.0	0.0	0.0	0.4	0.5	2.6
st dev	0.76	0.67	0.80	0.53	0.00	0.00	0.00	0.00	0.00	0.13	0.76	0.72	1.85
median	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	2.0
90%	1.1	1.0	1.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0	1.1	5.0
10%	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0
max	4.0	3.0	4.0	3.0	0.0	0.0	0.0	0.0	0.0	1.0	4.0	3.0	8.0
min	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Number of Days with Snowfall of 6.0 inches and greater (1891 through 2011)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Season
avg.	0.2	0.2	0.3	0.1	0.0	0.0	0.0	0.0	0.0	0.0	0.2	0.2	1.1
st dev	0.39	0.38	0.57	0.37	0.00	0.00	0.00	0.00	0.00	0.09	0.47	0.47	1.14
median	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0
90%	1.0	1.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0	1.0	3.0
10%	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
max	2.0	2.0	3.0	2.0	0.0	0.0	0.0	0.0	0.0	1.0	3.0	2.0	5.0
min	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Number of Days with Snowfall of 8.0 inches and greater (1891 through 2011)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Season
avg.	0.1	0.1	0.2	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.1	0.1	0.5
st dev	0.25	0.22	0.47	0.22	0.00	0.00	0.00	0.00	0.00	0.09	0.33	0.25	0.74
median	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
90%	0.0	0.0	1.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	1.0
10%	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
max	2.0	1.0	3.0	1.0	0.0	0.0	0.0	0.0	0.0	1.0	2.0	1.0	4.0
min	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Long-Term Monthly/Seasonal Snowfall Total Statistics in inches (1891 through 2011)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Season
avg.	10.0	8.1	9.6	3.6	0.2	0.0	0.0	0.0	0.0	0.8	6.2	9.3	46.6
st dev	7.43	5.28	7.73	4.34	0.65	0.00	0.00	0.00	0.16	1.47	6.91	7.18	18.49
median	8.3	7.4	8.2	1.9	0.0	0.0	0.0	0.0	0.0	0.1	4.4	7.3	44.5
90%	18.5	15.0	18.0	9.1	0.5	0.0	0.0	0.0	0.0	2.7	13.6	18.4	73.6
10%	3.2	2.1	1.4	0.1	0.0	0.0	0.0	0.0	0.0	0.0	0.6	2.0	24.9
max	46.4	26.5	40.0	21.8	3.0	0.0	0.0	0.0	1.7	8.2	46.9	33.6	98.6
min	0.6	0.3	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.1	0.6	14.2

Seasonal Snow Totals Time Series
click on time-trend graphic to enlarge

Note: The 1981-2010 annual snowfall normal for the Twin Cities is 54.0 inches, which is 7.4 inches more than the 120-year long-term average of 46.6 inches. The 30-year period, 1981-2010 is used in many climate summaries as a historical benchmark.