Hennepin Canal Parkway State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hennepin Canal Parkway State Park clear sky chart from 2005-11-06 to 2026-01-17.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	13% 8% 3 8% 5% 4 4 4 6% 7% 38%	127635
	Night	13% 9% 3 8% 5% 4 4 3 5% 6% 39%	124324
Transparency	Day	44% 4 12% 24% 14% 2	131142
	Night	45% 4 11% 23% 15% 2	128891
Seeing	Day	16% 10% 28% 26% 15% 5%	17409
	Night	17% 10% 31% 29% 12% 1	27330

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	10% 12% 6% 15% 7% 6% 5% 4 5% 6% 25%	3697
	11th to 20th	Day	9% 10% 6% 13% 6% 6% 6% 4 6% 5% 29%	3668
	21st to end	Day	14% 14% 7% 9% 5% 5% 4 3 4 5% 28%	4373
February	1st to 10th	Day	15% 12% 5% 11% 6% 5% 5% 3 4 6% 28%	1800
	11th to 20th	Day	13% 10% 4 9% 7% 5% 4 4 4 6% 35%	1903
	21st to end	Day	13% 12% 5% 10% 5% 4 3 4 5% 6% 33%	1650
March	1st to 10th	Day	18% 11% 4 6% 3 2 3 2 3 5% 42%	4480
	11th to 20th	Day	10% 6% 2 6% 5% 5% 4 4 6% 7% 46%	4878
	21st to end	Day	20% 11% 4 10% 5% 5% 5% 4 5% 6% 26%	5865
April	1st to 10th	Day	15% 13% 4 8% 5% 4 4 3 6% 6% 33%	2400
	11th to 20th	Day	16% 10% 4 6% 5% 3 4 3 5% 6% 37%	2374
	21st to end	Day	20% 8% 3 7% 5% 4 4 4 5% 6% 34%	2401
May	1st to 10th	Day	16% 8% 3 7% 4 5% 5% 4 6% 8% 36%	5949
	11th to 20th	Day	15% 6% 2 6% 4 4 4 3 6% 7% 43%	6319
	21st to end	Day	13% 7% 2 7% 4 5% 5% 4 6% 8% 39%	6935
June	1st to 10th	Day	10% 5% 2 5% 4 5% 5% 4 7% 8% 45%	2800
	11th to 20th	Day	8% 5% 2 6% 5% 4 4 5% 6% 8% 47%	2800
	21st to end	Day	11% 6% 2 6% 5% 5% 5% 4 7% 9% 41%	2800
July	1st to 10th	Day	8% 7% 3 7% 5% 5% 5% 4 7% 10% 39%	6360
	11th to 20th	Day	10% 5% 2 6% 4 5% 5% 4 7% 9% 42%	6360
	21st to end	Day	11% 6% 2 7% 6% 5% 5% 4 7% 9% 38%	6924
August	1st to 10th	Day	8% 5% 2 6% 4 5% 5% 4 7% 9% 44%	4338
	11th to 20th	Day	11% 6% 2 5% 4 4 5% 4 7% 10% 43%	3888
	21st to end	Day	8% 5% 2 6% 4 4 4 4 6% 8% 51%	4312
September	1st to 10th	Day	11% 5% 2 6% 4 3 4 4 5% 7% 48%	2400
	11th to 20th	Day	12% 4 1 4 3 3 3 3 5% 7% 55%	2345
	21st to end	Day	9% 5% 2 7% 4 5% 4 4 5% 7% 48%	2200
October	1st to 10th	Day	12% 6% 2 5% 4 4 4 3 5% 5% 50%	2034
	11th to 20th	Day	16% 8% 3 7% 4 3 4 3 5% 5% 42%	2000
	21st to end	Day	19% 8% 3 5% 4 3 4 3 5% 5% 41%	2065
November	1st to 10th	Day	11% 8% 2 6% 4 4 3 3 6% 7% 46%	1852
	11th to 20th	Day	16% 11% 3 8% 4 4 4 3 5% 6% 35%	1890
	21st to end	Day	16% 13% 4 8% 4 4 4 3 4 6% 35%	1727
December	1st to 10th	Day	8% 9% 4 7% 5% 4 3 3 4 5% 47%	2690
	11th to 20th	Day	13% 14% 5% 14% 6% 6% 4 3 6% 6% 22%	3088
	21st to end	Day	24% 20% 8% 12% 6% 3 3 2 3 4 14%	4070
January	1st to 10th	Night	12% 12% 6% 13% 5% 4 4 3 4 5% 32%	6488
	11th to 20th	Night	11% 14% 6% 13% 7% 6% 4 4 6% 4 24%	6445
	21st to end	Night	15% 14% 5% 10% 5% 4 4 3 4 4 32%	6600
February	1st to 10th	Night	15% 12% 5% 9% 5% 4 4 3 5% 5% 33%	2600
	11th to 20th	Night	13% 10% 4 8% 5% 4 4 4 5% 5% 38%	2382
	21st to end	Night	15% 10% 4 9% 5% 3 3 3 4 5% 39%	1980
March	1st to 10th	Night	17% 9% 3 6% 3 4 4 3 4 5% 41%	5373
	11th to 20th	Night	11% 6% 2 6% 4 4 4 3 5% 7% 48%	5123
	21st to end	Night	18% 11% 5% 10% 5% 5% 4 3 5% 6% 28%	5064
April	1st to 10th	Night	16% 10% 2 6% 4 3 4 3 5% 6% 40%	2000
	11th to 20th	Night	17% 9% 3 6% 4 3 4 3 4 5% 41%	1975
	21st to end	Night	15% 8% 3 8% 6% 4 4 3 5% 8% 36%	1997
May	1st to 10th	Night	18% 8% 3 7% 5% 4 5% 4 4 6% 35%	3946
	11th to 20th	Night	11% 6% 2 5% 5% 4 5% 4 7% 9% 43%	3596
	21st to end	Night	13% 7% 2 6% 5% 4 4 4 5% 8% 42%	3942
June	1st to 10th	Night	9% 5% 1 6% 3 4 5% 4 5% 7% 51%	1600
	11th to 20th	Night	8% 4 2 5% 4 5% 5% 5% 6% 9% 48%	1600
	21st to end	Night	9% 5% 2 5% 5% 5% 6% 4 6% 8% 46%	1600
July	1st to 10th	Night	12% 5% 2 7% 4 4 4 4 6% 8% 42%	3618
	11th to 20th	Night	8% 4 2 6% 4 4 4 3 6% 9% 51%	3617
	21st to end	Night	10% 5% 2 7% 5% 4 5% 4 6% 7% 43%	3947
August	1st to 10th	Night	5% 4 2 5% 4 3 4 4 7% 8% 54%	2818
	11th to 20th	Night	8% 5% 2 6% 4 3 5% 3 6% 8% 51%	3161
	21st to end	Night	7% 4 2 5% 4 4 4 4 5% 9% 54%	3586
September	1st to 10th	Night	11% 5% 1 4 3 3 3 3 5% 6% 57%	2000
	11th to 20th	Night	9% 4 2 4 4 4 4 3 6% 8% 53%	2035
	21st to end	Night	9% 5% 2 5% 4 4 4 5% 6% 7% 49%	2200
October	1st to 10th	Night	10% 5% 2 6% 3 4 4 2 4 5% 55%	2363
	11th to 20th	Night	15% 7% 3 6% 3 3 3 3 5% 6% 46%	2400
	21st to end	Night	19% 9% 2 6% 4 4 4 3 5% 5% 40%	2775
November	1st to 10th	Night	11% 8% 2 4 4 2 3 3 6% 7% 51%	2666
	11th to 20th	Night	14% 10% 3 7% 4 4 4 4 5% 7% 39%	2730
	21st to end	Night	16% 10% 3 8% 4 4 4 4 4 5% 37%	2888
December	1st to 10th	Night	9% 9% 3 7% 4 4 4 3 6% 6% 44%	4720
	11th to 20th	Night	15% 14% 5% 10% 5% 3 3 3 4 6% 33%	5339
	21st to end	Night	23% 17% 6% 11% 6% 5% 4 3 4 4 16%	7150

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	60% 3 12% 18% 7% 1	3698
	11th to 20th	Day	56% 3 10% 12% 15% 4	3668
	21st to end	Day	60% 2 13% 17% 8%	4373
February	1st to 10th	Day	58% 3 13% 16% 8% 2	1800
	11th to 20th	Day	50% 4 12% 22% 10% 2	1913
	21st to end	Day	52% 4 12% 20% 10% 2	1650
March	1st to 10th	Day	47% 3 9% 25% 13% 3	4480
	11th to 20th	Day	37% 3 11% 34% 14% 1	4878
	21st to end	Day	59% 4 13% 17% 6% 1	5867
April	1st to 10th	Day	51% 4 12% 22% 11% 1	2400
	11th to 20th	Day	48% 4 10% 24% 12% 2	2374
	21st to end	Day	51% 5% 10% 21% 12% 2	2401
May	1st to 10th	Day	46% 4 11% 22% 16% 1	5984
	11th to 20th	Day	41% 5% 11% 28% 13% 3	6323
	21st to end	Day	42% 5% 12% 24% 14% 3	6949
June	1st to 10th	Day	35% 5% 14% 27% 17% 2	2800
	11th to 20th	Day	34% 6% 11% 23% 22% 3	2800
	21st to end	Day	40% 6% 13% 24% 15% 2	2800
July	1st to 10th	Day	39% 5% 14% 26% 14% 1	6291
	11th to 20th	Day	37% 6% 14% 28% 14% 1	6285
	21st to end	Day	41% 6% 18% 20% 14% 1	6728
August	1st to 10th	Day	34% 7% 17% 29% 13% 1	4323
	11th to 20th	Day	35% 6% 15% 28% 15% 1	3924
	21st to end	Day	31% 5% 11% 33% 17% 2	4311
September	1st to 10th	Day	34% 5% 10% 26% 21% 4	2400
	11th to 20th	Day	29% 4 11% 30% 23% 3	2345
	21st to end	Day	35% 5% 9% 28% 22% 2	2200
October	1st to 10th	Day	24% 3 6% 28% 37% 1	3307
	11th to 20th	Day	30% 2 11% 24% 30% 3	3240
	21st to end	Day	41% 3 9% 27% 16% 4	3316
November	1st to 10th	Day	38% 3 14% 27% 15% 3	1852
	11th to 20th	Day	50% 3 12% 23% 11% 1	1890
	21st to end	Day	51% 5% 12% 23% 8%	1727
December	1st to 10th	Day	41% 3 14% 33% 8% 1	2690
	11th to 20th	Day	62% 3 12% 15% 6% 1	3085
	21st to end	Day	76% 3 8% 8% 4	4070
January	1st to 10th	Night	55% 3 11% 22% 9%	6488
	11th to 20th	Night	62% 2 11% 10% 14% 1	6445
	21st to end	Night	57% 3 10% 18% 12% 1	6600
February	1st to 10th	Night	53% 3 11% 18% 12% 1	2600
	11th to 20th	Night	48% 3 11% 23% 14% 1	2383
	21st to end	Night	49% 2 11% 22% 14% 2	1980
March	1st to 10th	Night	46% 2 10% 24% 13% 4	5373
	11th to 20th	Night	36% 3 10% 29% 17% 4	5123
	21st to end	Night	58% 4 11% 18% 8% 1	5064
April	1st to 10th	Night	46% 4 11% 24% 14% 2	2000
	11th to 20th	Night	45% 3 8% 24% 15% 4	1975
	21st to end	Night	47% 4 11% 23% 12% 3	1997
May	1st to 10th	Night	49% 5% 10% 18% 16% 3	3973
	11th to 20th	Night	38% 5% 15% 26% 13% 4	3597
	21st to end	Night	41% 5% 11% 26% 16% 2	3950
June	1st to 10th	Night	32% 5% 15% 26% 20% 3	1600
	11th to 20th	Night	33% 5% 11% 25% 22% 4	1600
	21st to end	Night	35% 8% 14% 22% 19% 3	1600
July	1st to 10th	Night	39% 4 13% 25% 16% 2	3580
	11th to 20th	Night	31% 5% 14% 29% 20% 1	3572
	21st to end	Night	38% 7% 15% 22% 15% 3	3832
August	1st to 10th	Night	27% 5% 17% 31% 19% 2	2809
	11th to 20th	Night	30% 6% 16% 31% 17% 1	3191
	21st to end	Night	28% 5% 12% 32% 19% 3	3586
September	1st to 10th	Night	28% 4 9% 29% 26% 4	2000
	11th to 20th	Night	30% 4 10% 30% 22% 4	2035
	21st to end	Night	32% 5% 11% 26% 22% 3	2200
October	1st to 10th	Night	23% 2 7% 32% 33% 3	3870
	11th to 20th	Night	29% 3 9% 22% 33% 4	3899
	21st to end	Night	40% 3 10% 24% 20% 3	4474
November	1st to 10th	Night	34% 4 12% 28% 18% 4	2666
	11th to 20th	Night	45% 3 12% 25% 14% 2	2730
	21st to end	Night	50% 3 10% 24% 13% 1	2888
December	1st to 10th	Night	41% 2 14% 31% 11% 1	4720
	11th to 20th	Night	55% 2 12% 20% 10% 1	5341
	21st to end	Night	72% 3 9% 11% 5%	7150

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	18% 14% 37% 23% 7% 1	330
	11th to 20th	Day	20% 19% 39% 18% 3 1	318
	21st to end	Day	18% 20% 35% 21% 5% 1	330
February	1st to 10th	Day	21% 15% 40% 20% 4	300
	11th to 20th	Day	21% 19% 37% 16% 6% 1	300
	21st to end	Day	21% 16% 44% 18% 2	249
March	1st to 10th	Day	22% 20% 36% 18% 4	300
	11th to 20th	Day	23% 19% 34% 17% 6% 1	300
	21st to end	Day	29% 14% 34% 16% 6% 1	500
April	1st to 10th	Day	24% 15% 32% 23% 4 1	500
	11th to 20th	Day	22% 18% 29% 18% 11% 2	492
	21st to end	Day	24% 11% 34% 21% 8% 1	500
May	1st to 10th	Day	17% 12% 33% 26% 8% 3	538
	11th to 20th	Day	22% 11% 26% 24% 14% 4	725
	21st to end	Day	15% 9% 28% 27% 13% 7%	789
June	1st to 10th	Day	11% 7% 27% 29% 20% 6%	730
	11th to 20th	Day	10% 3 29% 32% 21% 4	730
	21st to end	Day	12% 7% 30% 31% 15% 5%	730
July	1st to 10th	Day	9% 3 17% 29% 26% 15%	721
	11th to 20th	Day	10% 4 22% 30% 25% 9%	718
	21st to end	Day	8% 3 20% 34% 27% 8%	794
August	1st to 10th	Day	8% 4 19% 34% 26% 9%	726
	11th to 20th	Day	11% 3 19% 28% 25% 13%	546
	21st to end	Day	7% 4 15% 35% 29% 10%	583
September	1st to 10th	Day	13% 6% 17% 30% 26% 7%	530
	11th to 20th	Day	10% 3 15% 31% 31% 11%	530
	21st to end	Day	9% 8% 27% 27% 21% 7%	530
October	1st to 10th	Day	14% 9% 25% 28% 18% 5%	364
	11th to 20th	Day	18% 21% 32% 21% 8%	330
	21st to end	Day	28% 15% 29% 23% 4 1	363
November	1st to 10th	Day	15% 14% 38% 22% 8% 3	330
	11th to 20th	Day	21% 21% 30% 19% 8% 2	330
	21st to end	Day	26% 13% 32% 23% 6%	330
December	1st to 10th	Day	15% 16% 42% 20% 5% 2	330
	11th to 20th	Day	19% 13% 36% 26% 5%	330
	21st to end	Day	26% 18% 38% 14% 4	363
January	1st to 10th	Night	18% 14% 38% 24% 5%	1050
	11th to 20th	Night	19% 15% 40% 20% 5% 1	1031
	21st to end	Night	20% 14% 36% 25% 4	1100
February	1st to 10th	Night	23% 13% 38% 23% 4	1000
	11th to 20th	Night	18% 14% 38% 26% 4	827
	21st to end	Night	22% 13% 42% 20% 3 1	660
March	1st to 10th	Night	20% 13% 38% 23% 5% 1	800
	11th to 20th	Night	19% 11% 33% 30% 7%	665
	21st to end	Night	23% 13% 36% 21% 6% 1	660
April	1st to 10th	Night	22% 12% 36% 25% 5%	600
	11th to 20th	Night	22% 13% 31% 28% 6%	593
	21st to end	Night	18% 14% 33% 30% 6%	600
May	1st to 10th	Night	20% 9% 34% 28% 9% 1	600
	11th to 20th	Night	18% 7% 28% 35% 10% 1	591
	21st to end	Night	13% 6% 29% 34% 17% 1	650
June	1st to 10th	Night	11% 4 24% 46% 15% 1	600
	11th to 20th	Night	9% 4 31% 40% 16%	600
	21st to end	Night	10% 5% 29% 39% 16% 1	600
July	1st to 10th	Night	9% 3 13% 40% 30% 5%	585
	11th to 20th	Night	8% 1 18% 45% 24% 4	582
	21st to end	Night	6% 2 16% 46% 29% 1	657
August	1st to 10th	Night	6% 2 16% 42% 30% 4	597
	11th to 20th	Night	7% 3 13% 40% 33% 5%	594
	21st to end	Night	9% 1 14% 43% 31% 2	660
September	1st to 10th	Night	12% 5% 16% 37% 27% 3	600
	11th to 20th	Night	11% 3 17% 37% 28% 4	635
	21st to end	Night	11% 7% 24% 34% 22% 2	800
October	1st to 10th	Night	12% 6% 30% 33% 18% 2	800
	11th to 20th	Night	18% 13% 31% 27% 11%	800
	21st to end	Night	24% 11% 33% 24% 7%	880
November	1st to 10th	Night	16% 12% 37% 25% 9% 1	820
	11th to 20th	Night	19% 13% 38% 23% 5%	840
	21st to end	Night	22% 13% 34% 24% 6%	998
December	1st to 10th	Night	21% 13% 38% 23% 5%	1050
	11th to 20th	Night	21% 13% 35% 25% 6%	1050
	21st to end	Night	30% 14% 33% 21% 3	1155

Page generated at 2026-01-14 00:14:31. Version ac07

Copyright © 2026 Attilla Danko.