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 2024-11-25.

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 7% 5% 4 4 4 6% 7% 38%	101584
	Night	14% 9% 3 7% 4 4 4 3 5% 6% 40%	97978
Transparency	Day	43% 5% 12% 23% 15% 2	105136
	Night	44% 4 12% 23% 16% 2	102567
Seeing	Day	16% 10% 28% 26% 15% 5%	15867
	Night	17% 10% 31% 30% 12% 1	25714

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	11% 12% 7% 15% 7% 6% 5% 4 5% 6% 24%	2527
	11th to 20th	Day	12% 12% 4 15% 7% 6% 7% 5% 7% 5% 20%	2530
	21st to end	Day	17% 19% 10% 11% 6% 4 4 3 4 4 19%	3048
February	1st to 10th	Day	15% 12% 5% 10% 6% 4 5% 3 4 6% 29%	1710
	11th to 20th	Day	13% 10% 3 8% 6% 5% 4 4 4 6% 35%	1805
	21st to end	Day	14% 13% 6% 10% 5% 4 3 4 5% 6% 31%	1570
March	1st to 10th	Day	15% 14% 4 7% 4 3 3 3 4 6% 38%	3120
	11th to 20th	Day	10% 6% 3 6% 5% 5% 4 4 6% 7% 45%	3406
	21st to end	Day	20% 12% 4 10% 5% 5% 5% 4 5% 6% 24%	4091
April	1st to 10th	Day	15% 13% 4 8% 5% 4 4 3 6% 6% 34%	2280
	11th to 20th	Day	17% 10% 4 6% 5% 4 4 3 5% 6% 37%	2254
	21st to end	Day	21% 8% 3 7% 5% 4 4 3 5% 6% 34%	2281
May	1st to 10th	Day	16% 7% 3 7% 5% 5% 5% 4 6% 8% 35%	4141
	11th to 20th	Day	17% 6% 3 6% 4 4 4 3 5% 7% 41%	4399
	21st to end	Day	11% 6% 2 6% 4 4 4 3 6% 9% 44%	4824
June	1st to 10th	Day	10% 5% 2 5% 4 5% 5% 4 7% 8% 46%	2660
	11th to 20th	Day	8% 5% 2 6% 5% 4 4 4 6% 8% 47%	2660
	21st to end	Day	11% 6% 2 6% 5% 5% 5% 4 7% 9% 39%	2660
July	1st to 10th	Day	9% 8% 3 7% 6% 5% 6% 5% 8% 9% 35%	4440
	11th to 20th	Day	7% 4 2 5% 4 4 5% 4 6% 9% 51%	4440
	21st to end	Day	9% 6% 2 6% 6% 5% 5% 4 7% 10% 42%	4813
August	1st to 10th	Day	8% 5% 2 6% 4 5% 5% 5% 7% 9% 44%	4205
	11th to 20th	Day	11% 6% 2 5% 4 4 5% 4 7% 10% 43%	3767
	21st to end	Day	8% 5% 2 6% 4 4 4 4 6% 8% 51%	4180
September	1st to 10th	Day	12% 5% 2 6% 4 3 4 4 5% 7% 47%	2280
	11th to 20th	Day	12% 4 1 4 3 3 3 3 5% 7% 54%	2228
	21st to end	Day	10% 5% 2 7% 4 4 4 4 5% 7% 48%	2090
October	1st to 10th	Day	12% 6% 2 5% 4 4 4 3 5% 5% 50%	1933
	11th to 20th	Day	16% 8% 3 7% 4 3 4 2 6% 5% 42%	1900
	21st to end	Day	19% 9% 3 6% 4 3 4 3 5% 5% 40%	1962
November	1st to 10th	Day	11% 8% 2 7% 4 4 4 3 6% 6% 46%	1762
	11th to 20th	Day	16% 11% 3 8% 4 4 4 3 5% 6% 35%	1800
	21st to end	Day	16% 13% 4 8% 4 4 4 3 3 6% 36%	1597
December	1st to 10th	Day	13% 13% 5% 8% 6% 4 4 4 4 5% 35%	1520
	11th to 20th	Day	12% 14% 3 11% 6% 6% 4 3 6% 5% 29%	1918
	21st to end	Day	24% 19% 8% 12% 6% 3 3 3 3 4 16%	2783
January	1st to 10th	Night	14% 12% 6% 13% 5% 4 4 3 4 5% 31%	4428
	11th to 20th	Night	13% 17% 6% 12% 6% 5% 4 5% 7% 4 22%	4440
	21st to end	Night	19% 17% 7% 12% 5% 4 3 3 3 4 23%	4614
February	1st to 10th	Night	15% 12% 5% 8% 5% 4 4 3 5% 5% 33%	2470
	11th to 20th	Night	13% 10% 4 8% 5% 4 4 4 5% 5% 39%	2260
	21st to end	Night	16% 10% 4 10% 5% 4 3 3 4 5% 37%	1884
March	1st to 10th	Night	18% 10% 2 6% 3 4 4 3 4 5% 41%	3733
	11th to 20th	Night	11% 6% 2 6% 4 4 4 3 5% 7% 48%	3581
	21st to end	Night	23% 10% 6% 10% 5% 4 4 3 5% 5% 25%	3540
April	1st to 10th	Night	16% 11% 2 6% 4 3 3 3 5% 6% 39%	1900
	11th to 20th	Night	17% 9% 3 5% 4 3 4 3 4 5% 42%	1875
	21st to end	Night	16% 8% 2 8% 6% 4 4 3 5% 8% 36%	1897
May	1st to 10th	Night	17% 7% 2 7% 6% 4 6% 5% 5% 7% 33%	2752
	11th to 20th	Night	13% 6% 2 5% 5% 4 4 4 7% 8% 41%	2506
	21st to end	Night	9% 6% 2 5% 5% 4 4 4 5% 8% 47%	2743
June	1st to 10th	Night	9% 6% 2 6% 3 4 4 4 5% 7% 50%	1520
	11th to 20th	Night	8% 4 2 5% 4 5% 5% 5% 6% 8% 48%	1520
	21st to end	Night	9% 5% 2 5% 5% 5% 6% 3 6% 8% 46%	1520
July	1st to 10th	Night	14% 5% 2 7% 4 5% 4 4 6% 7% 41%	2530
	11th to 20th	Night	6% 3 1 5% 3 4 4 3 6% 8% 57%	2530
	21st to end	Night	6% 4 2 7% 5% 4 6% 5% 6% 8% 47%	2750
August	1st to 10th	Night	6% 4 2 5% 4 3 4 4 6% 8% 54%	2731
	11th to 20th	Night	8% 5% 2 5% 4 3 5% 3 6% 8% 52%	3062
	21st to end	Night	7% 4 2 5% 4 4 4 4 5% 9% 54%	3476
September	1st to 10th	Night	11% 5% 1 4 3 3 3 3 4 6% 57%	1900
	11th to 20th	Night	9% 4 2 4 4 4 4 3 6% 7% 53%	1933
	21st to end	Night	9% 4 3 5% 4 4 4 5% 6% 7% 48%	2090
October	1st to 10th	Night	10% 5% 2 6% 3 4 4 2 4 5% 54%	2245
	11th to 20th	Night	15% 7% 3 6% 3 3 3 3 4 6% 47%	2280
	21st to end	Night	19% 9% 2 6% 4 4 4 3 5% 6% 39%	2636
November	1st to 10th	Night	11% 8% 2 4 3 2 3 3 6% 6% 51%	2536
	11th to 20th	Night	14% 10% 3 7% 4 4 4 4 5% 7% 39%	2600
	21st to end	Night	16% 10% 4 7% 5% 4 4 4 4 5% 38%	2673
December	1st to 10th	Night	15% 11% 4 8% 5% 5% 4 3 5% 6% 34%	2660
	11th to 20th	Night	14% 13% 5% 9% 5% 4 3 3 4 6% 34%	3279
	21st to end	Night	22% 16% 6% 11% 6% 5% 4 3 4 4 18%	4884

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	61% 3 13% 16% 6%	2528
	11th to 20th	Day	64% 4 11% 13% 8% 1	2530
	21st to end	Day	70% 3 9% 12% 6%	3048
February	1st to 10th	Day	57% 3 13% 17% 8% 2	1710
	11th to 20th	Day	49% 4 12% 23% 10% 1	1815
	21st to end	Day	54% 4 11% 20% 9% 2	1570
March	1st to 10th	Day	49% 4 13% 20% 13% 2	3120
	11th to 20th	Day	39% 3 14% 30% 13% 1	3406
	21st to end	Day	61% 4 15% 16% 3 1	4091
April	1st to 10th	Day	50% 4 12% 23% 11% 1	2280
	11th to 20th	Day	48% 4 9% 24% 13% 2	2254
	21st to end	Day	51% 5% 10% 20% 12% 2	2281
May	1st to 10th	Day	46% 5% 12% 23% 13%	4179
	11th to 20th	Day	44% 5% 10% 30% 12%	4403
	21st to end	Day	37% 6% 12% 22% 19% 4	4837
June	1st to 10th	Day	35% 6% 14% 27% 17% 2	2660
	11th to 20th	Day	34% 7% 11% 23% 23% 3	2660
	21st to end	Day	41% 6% 12% 24% 14% 3	2660
July	1st to 10th	Day	43% 5% 13% 24% 12% 2	4371
	11th to 20th	Day	29% 6% 16% 31% 17% 2	4365
	21st to end	Day	36% 6% 18% 19% 19% 2	4662
August	1st to 10th	Day	34% 7% 17% 29% 13% 1	4190
	11th to 20th	Day	35% 6% 15% 27% 15% 1	3803
	21st to end	Day	32% 5% 11% 33% 17% 3	4179
September	1st to 10th	Day	35% 6% 10% 24% 21% 4	2280
	11th to 20th	Day	30% 4 11% 29% 23% 3	2228
	21st to end	Day	35% 5% 9% 28% 21% 2	2090
October	1st to 10th	Day	24% 3 6% 29% 37% 1	3206
	11th to 20th	Day	29% 2 11% 24% 31% 3	3140
	21st to end	Day	41% 3 9% 27% 16% 4	3213
November	1st to 10th	Day	38% 3 15% 26% 15% 3	1762
	11th to 20th	Day	50% 3 12% 22% 11% 2	1800
	21st to end	Day	51% 5% 12% 23% 8%	1597
December	1st to 10th	Day	53% 4 13% 20% 9% 1	1520
	11th to 20th	Day	56% 4 13% 20% 8% 1	1915
	21st to end	Day	74% 3 9% 9% 5%	2783
January	1st to 10th	Night	56% 3 12% 20% 9%	4428
	11th to 20th	Night	63% 2 11% 13% 10%	4440
	21st to end	Night	66% 3 10% 14% 6% 1	4614
February	1st to 10th	Night	53% 4 11% 18% 12% 2	2470
	11th to 20th	Night	46% 4 12% 24% 14% 1	2261
	21st to end	Night	50% 3 10% 22% 13% 3	1884
March	1st to 10th	Night	47% 3 12% 24% 13% 2	3733
	11th to 20th	Night	36% 4 11% 29% 18% 3	3581
	21st to end	Night	62% 3 12% 17% 6% 1	3540
April	1st to 10th	Night	46% 4 11% 23% 14% 2	1900
	11th to 20th	Night	45% 4 8% 24% 16% 4	1875
	21st to end	Night	47% 4 11% 22% 12% 3	1897
May	1st to 10th	Night	48% 5% 12% 19% 14% 2	2779
	11th to 20th	Night	40% 4 18% 27% 10% 1	2507
	21st to end	Night	33% 6% 12% 24% 22% 3	2751
June	1st to 10th	Night	32% 5% 15% 25% 20% 3	1520
	11th to 20th	Night	32% 5% 11% 24% 23% 4	1520
	21st to end	Night	35% 8% 14% 21% 19% 3	1520
July	1st to 10th	Night	42% 4 14% 23% 14% 3	2490
	11th to 20th	Night	26% 4 13% 32% 22% 2	2482
	21st to end	Night	33% 7% 16% 21% 19% 5%	2662
August	1st to 10th	Night	27% 5% 17% 31% 19% 2	2722
	11th to 20th	Night	30% 6% 15% 31% 17% 1	3092
	21st to end	Night	29% 5% 12% 32% 19% 3	3476
September	1st to 10th	Night	29% 4 10% 27% 26% 4	1900
	11th to 20th	Night	30% 4 10% 30% 22% 4	1933
	21st to end	Night	32% 5% 11% 27% 21% 3	2090
October	1st to 10th	Night	23% 2 7% 32% 32% 3	3752
	11th to 20th	Night	29% 3 9% 22% 33% 4	3779
	21st to end	Night	40% 3 10% 24% 19% 3	4335
November	1st to 10th	Night	34% 4 12% 28% 18% 4	2536
	11th to 20th	Night	45% 3 12% 24% 14% 2	2600
	21st to end	Night	49% 3 10% 24% 13% 1	2673
December	1st to 10th	Night	51% 3 13% 22% 9% 1	2660
	11th to 20th	Night	52% 3 12% 23% 9% 1	3281
	21st to end	Night	70% 3 9% 12% 5%	4884

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	20% 14% 36% 23% 7% 1	270
	11th to 20th	Day	23% 17% 37% 19% 4 1	270
	21st to end	Day	19% 19% 34% 22% 6% 1	297
February	1st to 10th	Day	20% 14% 41% 20% 4	270
	11th to 20th	Day	22% 16% 36% 18% 7% 1	270
	21st to end	Day	21% 16% 43% 18% 2	225
March	1st to 10th	Day	21% 21% 36% 18% 4	270
	11th to 20th	Day	22% 19% 34% 17% 7% 1	270
	21st to end	Day	29% 12% 34% 17% 6% 1	458
April	1st to 10th	Day	23% 14% 32% 24% 5% 1	460
	11th to 20th	Day	21% 17% 29% 18% 12% 2	452
	21st to end	Day	26% 11% 33% 21% 8% 2	460
May	1st to 10th	Day	18% 12% 33% 27% 8% 2	496
	11th to 20th	Day	22% 10% 26% 24% 14% 3	675
	21st to end	Day	15% 9% 27% 27% 14% 8%	734
June	1st to 10th	Day	10% 6% 27% 29% 20% 7%	680
	11th to 20th	Day	9% 3 30% 33% 21% 4	680
	21st to end	Day	12% 7% 30% 30% 15% 5%	680
July	1st to 10th	Day	10% 3 17% 30% 25% 15%	671
	11th to 20th	Day	10% 4 22% 30% 25% 9%	668
	21st to end	Day	8% 3 20% 34% 27% 8%	739
August	1st to 10th	Day	8% 3 19% 35% 26% 9%	676
	11th to 20th	Day	11% 4 19% 29% 24% 13%	505
	21st to end	Day	7% 4 14% 35% 29% 10%	539
September	1st to 10th	Day	14% 6% 17% 31% 25% 7%	490
	11th to 20th	Day	10% 3 16% 31% 29% 11%	490
	21st to end	Day	10% 9% 29% 26% 21% 5%	490
October	1st to 10th	Day	15% 9% 26% 28% 17% 5%	333
	11th to 20th	Day	18% 22% 32% 19% 9%	300
	21st to end	Day	29% 14% 29% 23% 4 1	330
November	1st to 10th	Day	16% 12% 37% 21% 9% 4	300
	11th to 20th	Day	20% 20% 31% 19% 8% 2	300
	21st to end	Day	27% 11% 32% 24% 6%	282
December	1st to 10th	Day	16% 17% 39% 20% 5% 3	270
	11th to 20th	Day	16% 13% 37% 28% 6%	270
	21st to end	Day	24% 19% 39% 15% 3	297
January	1st to 10th	Night	17% 14% 39% 23% 5%	950
	11th to 20th	Night	19% 14% 40% 21% 6% 1	950
	21st to end	Night	20% 13% 36% 26% 4	1045
February	1st to 10th	Night	23% 12% 38% 23% 4	950
	11th to 20th	Night	18% 14% 38% 27% 4	785
	21st to end	Night	22% 13% 41% 20% 3 1	628
March	1st to 10th	Night	20% 13% 38% 23% 5% 1	760
	11th to 20th	Night	19% 11% 32% 30% 7%	632
	21st to end	Night	23% 13% 36% 21% 6% 1	627
April	1st to 10th	Night	21% 12% 37% 24% 5%	570
	11th to 20th	Night	22% 13% 30% 29% 6%	563
	21st to end	Night	17% 14% 33% 29% 7%	570
May	1st to 10th	Night	19% 8% 35% 28% 8% 1	570
	11th to 20th	Night	19% 6% 28% 36% 10% 1	561
	21st to end	Night	12% 6% 29% 35% 17% 1	617
June	1st to 10th	Night	11% 4 24% 46% 15% 1	570
	11th to 20th	Night	9% 4 31% 41% 15%	570
	21st to end	Night	11% 5% 28% 40% 15% 1	570
July	1st to 10th	Night	9% 3 12% 40% 30% 5%	555
	11th to 20th	Night	7% 1 19% 44% 25% 4	552
	21st to end	Night	5% 2 16% 46% 30% 1	624
August	1st to 10th	Night	6% 2 16% 41% 30% 4	567
	11th to 20th	Night	7% 3 13% 40% 32% 5%	564
	21st to end	Night	10% 1 14% 42% 31% 2	627
September	1st to 10th	Night	13% 4 16% 37% 26% 3	570
	11th to 20th	Night	12% 2 18% 36% 28% 4	603
	21st to end	Night	11% 7% 25% 34% 21% 2	760
October	1st to 10th	Night	12% 6% 30% 32% 18% 2	760
	11th to 20th	Night	18% 13% 31% 27% 11%	760
	21st to end	Night	25% 11% 33% 24% 8%	836
November	1st to 10th	Night	16% 12% 37% 25% 9% 1	780
	11th to 20th	Night	19% 13% 38% 24% 6%	800
	21st to end	Night	21% 12% 34% 26% 6%	923
December	1st to 10th	Night	22% 12% 37% 22% 6%	950
	11th to 20th	Night	22% 11% 35% 25% 6%	950
	21st to end	Night	28% 15% 33% 21% 3	1045

Page generated at 2024-11-22 07:02:27. Version ac07

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