High Cliff State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the High Cliff State Park clear sky chart from 2005-11-06 to 2024-11-06.

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	12% 9% 3 8% 5% 4 5% 4 6% 7% 38%	101455
	Night	13% 10% 4 8% 5% 4 4 4 5% 6% 38%	97692
Transparency	Day	43% 7% 12% 24% 13% 1	104974
	Night	45% 6% 12% 23% 13% 2	102314
Seeing	Day	16% 10% 30% 26% 13% 4	15960
	Night	17% 9% 32% 30% 11% 1	25818

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% 13% 6% 13% 6% 5% 5% 3 5% 4 29%	2527
	11th to 20th	Day	11% 11% 5% 13% 7% 6% 9% 6% 7% 6% 19%	2530
	21st to end	Day	16% 16% 6% 15% 6% 5% 4 3 4 4 20%	2783
February	1st to 10th	Day	9% 12% 5% 12% 6% 5% 5% 4 5% 7% 31%	1691
	11th to 20th	Day	11% 11% 3 8% 5% 4 5% 3 5% 7% 37%	1813
	21st to end	Day	12% 12% 4 9% 6% 5% 4 3 5% 6% 33%	1570
March	1st to 10th	Day	12% 8% 2 6% 4 4 4 3 5% 7% 46%	3120
	11th to 20th	Day	10% 7% 3 8% 5% 4 4 4 5% 7% 43%	3271
	21st to end	Day	20% 12% 5% 10% 4 4 4 3 4 5% 29%	4165
April	1st to 10th	Day	15% 14% 3 7% 5% 5% 5% 4 5% 7% 30%	2280
	11th to 20th	Day	20% 10% 2 6% 5% 5% 4 4 5% 6% 34%	2254
	21st to end	Day	17% 9% 2 8% 5% 4 4 3 6% 6% 34%	2423
May	1st to 10th	Day	12% 8% 2 7% 5% 5% 5% 4 5% 7% 40%	4173
	11th to 20th	Day	12% 6% 2 6% 4 3 4 4 5% 8% 46%	4399
	21st to end	Day	12% 7% 2 7% 5% 4 5% 4 6% 8% 40%	4824
June	1st to 10th	Day	10% 6% 2 6% 5% 4 4 4 6% 9% 44%	2660
	11th to 20th	Day	13% 7% 2 5% 4 4 4 4 6% 10% 41%	2660
	21st to end	Day	10% 6% 2 6% 4 4 5% 4 7% 10% 43%	2660
July	1st to 10th	Day	12% 7% 2 6% 5% 5% 5% 5% 7% 10% 37%	4440
	11th to 20th	Day	5% 3 1 4 3 4 5% 5% 8% 10% 51%	4440
	21st to end	Day	7% 6% 2 6% 4 5% 5% 4 6% 8% 47%	4813
August	1st to 10th	Day	8% 6% 2 7% 5% 5% 5% 5% 6% 9% 42%	4423
	11th to 20th	Day	11% 5% 2 5% 4 4 4 4 6% 8% 47%	3896
	21st to end	Day	10% 7% 2 7% 5% 5% 5% 4 6% 8% 41%	4180
September	1st to 10th	Day	12% 5% 2 7% 4 4 5% 3 5% 7% 45%	2280
	11th to 20th	Day	11% 5% 2 5% 4 4 4 3 5% 9% 48%	2176
	21st to end	Day	12% 8% 3 7% 5% 4 4 4 6% 7% 41%	2090
October	1st to 10th	Day	13% 7% 2 6% 4 4 4 3 5% 6% 45%	2000
	11th to 20th	Day	19% 10% 4 7% 5% 5% 3 4 6% 7% 29%	1859
	21st to end	Day	16% 11% 3 8% 4 4 4 4 4 5% 36%	1881
November	1st to 10th	Day	14% 8% 3 6% 5% 4 5% 3 4 7% 41%	1717
	11th to 20th	Day	11% 12% 5% 10% 6% 5% 5% 4 6% 6% 29%	1710
	21st to end	Day	15% 12% 4 9% 5% 4 5% 4 4 6% 34%	1526
December	1st to 10th	Day	13% 12% 4 11% 9% 5% 5% 4 6% 6% 25%	1520
	11th to 20th	Day	12% 14% 5% 12% 7% 6% 6% 4 5% 5% 25%	1918
	21st to end	Day	17% 16% 6% 15% 8% 5% 5% 3 3 4 16%	2783
January	1st to 10th	Night	12% 15% 7% 11% 6% 4 3 2 3 4 33%	4428
	11th to 20th	Night	12% 13% 5% 15% 6% 5% 7% 6% 5% 5% 20%	4440
	21st to end	Night	14% 17% 6% 14% 5% 5% 4 3 4 5% 24%	4884
February	1st to 10th	Night	10% 14% 4 9% 6% 5% 5% 4 5% 6% 33%	2486
	11th to 20th	Night	10% 9% 4 9% 6% 6% 5% 4 4 4 39%	2252
	21st to end	Night	16% 13% 3 8% 4 4 4 3 5% 4 37%	1884
March	1st to 10th	Night	14% 8% 3 6% 4 3 4 4 6% 6% 43%	3733
	11th to 20th	Night	9% 8% 3 8% 6% 5% 5% 4 5% 7% 40%	3717
	21st to end	Night	19% 10% 4 10% 5% 4 4 4 5% 5% 30%	3466
April	1st to 10th	Night	18% 11% 4 8% 5% 4 4 2 5% 6% 35%	1900
	11th to 20th	Night	20% 8% 2 6% 5% 3 3 4 6% 6% 37%	1875
	21st to end	Night	17% 8% 2 8% 5% 5% 4 3 5% 6% 37%	1755
May	1st to 10th	Night	15% 7% 2 7% 5% 4 4 4 6% 8% 38%	2721
	11th to 20th	Night	11% 6% 2 7% 5% 4 6% 4 6% 7% 42%	2506
	21st to end	Night	16% 8% 3 8% 4 4 4 4 6% 6% 38%	2743
June	1st to 10th	Night	9% 6% 2 5% 5% 5% 4 3 7% 7% 47%	1520
	11th to 20th	Night	12% 6% 2 7% 3 3 3 4 7% 8% 44%	1520
	21st to end	Night	8% 5% 1 5% 4 4 5% 4 7% 9% 47%	1520
July	1st to 10th	Night	14% 8% 2 6% 3 4 4 4 5% 6% 43%	2530
	11th to 20th	Night	4 4 2 5% 3 4 4 4 5% 8% 56%	2530
	21st to end	Night	6% 5% 2 6% 4 4 5% 4 7% 9% 49%	2750
August	1st to 10th	Night	12% 5% 3 5% 4 4 4 4 5% 8% 47%	2517
	11th to 20th	Night	10% 7% 2 7% 4 4 4 3 5% 7% 47%	2928
	21st to end	Night	8% 5% 2 5% 4 5% 5% 4 6% 8% 48%	3476
September	1st to 10th	Night	10% 5% 2 5% 4 3 4 3 5% 7% 53%	1900
	11th to 20th	Night	12% 5% 1 5% 3 4 3 3 4 7% 53%	1984
	21st to end	Night	12% 6% 2 5% 4 4 4 3 6% 8% 46%	2090
October	1st to 10th	Night	12% 7% 3 5% 4 4 3 3 5% 7% 48%	2175
	11th to 20th	Night	15% 8% 3 7% 4 5% 5% 4 5% 7% 38%	2319
	21st to end	Night	17% 10% 3 7% 4 4 4 3 5% 7% 35%	2717
November	1st to 10th	Night	13% 9% 3 5% 5% 4 4 3 4 6% 44%	2483
	11th to 20th	Night	14% 12% 5% 9% 6% 5% 4 3 5% 5% 33%	2470
	21st to end	Night	15% 11% 3 7% 5% 4 4 3 4 6% 37%	2650
December	1st to 10th	Night	13% 13% 5% 10% 6% 5% 5% 4 5% 7% 28%	2660
	11th to 20th	Night	12% 16% 5% 11% 5% 5% 4 3 4 5% 29%	3279
	21st to end	Night	19% 19% 5% 11% 6% 5% 4 3 4 4 21%	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	57% 6% 15% 16% 5%	2528
	11th to 20th	Day	62% 7% 11% 15% 4	2530
	21st to end	Day	66% 5% 10% 14% 4	2783
February	1st to 10th	Day	52% 5% 12% 20% 10% 1	1691
	11th to 20th	Day	46% 6% 11% 24% 12% 1	1823
	21st to end	Day	52% 6% 11% 19% 10% 2	1570
March	1st to 10th	Day	38% 6% 12% 25% 16% 3	3120
	11th to 20th	Day	39% 7% 13% 25% 15% 2	3271
	21st to end	Day	58% 5% 9% 21% 6% 1	4165
April	1st to 10th	Day	52% 7% 12% 19% 10%	2280
	11th to 20th	Day	49% 6% 9% 21% 13% 2	2254
	21st to end	Day	49% 7% 12% 20% 12% 2	2423
May	1st to 10th	Day	41% 8% 12% 23% 16% 1	4211
	11th to 20th	Day	35% 6% 11% 32% 14% 1	4403
	21st to end	Day	40% 8% 11% 22% 16% 3	4837
June	1st to 10th	Day	36% 7% 13% 28% 15% 2	2660
	11th to 20th	Day	38% 7% 14% 26% 15% 1	2660
	21st to end	Day	34% 10% 14% 25% 15% 1	2660
July	1st to 10th	Day	40% 8% 14% 26% 11% 2	4371
	11th to 20th	Day	23% 9% 18% 33% 16% 2	4365
	21st to end	Day	33% 8% 13% 22% 22% 2	4662
August	1st to 10th	Day	36% 7% 15% 29% 12% 1	4408
	11th to 20th	Day	32% 7% 13% 35% 11% 1	3935
	21st to end	Day	39% 6% 14% 23% 16% 1	4179
September	1st to 10th	Day	37% 7% 13% 27% 15% 1	2280
	11th to 20th	Day	33% 6% 15% 33% 12% 1	2176
	21st to end	Day	41% 7% 12% 30% 10%	2090
October	1st to 10th	Day	25% 4 9% 37% 24% 1	3325
	11th to 20th	Day	44% 6% 9% 26% 15% 1	3062
	21st to end	Day	43% 5% 13% 26% 12%	3081
November	1st to 10th	Day	43% 5% 14% 24% 13% 1	1717
	11th to 20th	Day	54% 6% 15% 18% 7%	1710
	21st to end	Day	52% 5% 15% 21% 6% 1	1526
December	1st to 10th	Day	58% 7% 13% 18% 4 1	1520
	11th to 20th	Day	59% 5% 14% 14% 6% 2	1915
	21st to end	Day	72% 6% 8% 10% 5%	2783
January	1st to 10th	Night	57% 4 10% 20% 9% 1	4428
	11th to 20th	Night	64% 6% 10% 14% 6%	4440
	21st to end	Night	63% 5% 11% 15% 6%	4884
February	1st to 10th	Night	52% 5% 9% 21% 11% 2	2486
	11th to 20th	Night	48% 5% 10% 24% 12% 2	2253
	21st to end	Night	50% 4 13% 20% 11% 2	1884
March	1st to 10th	Night	40% 5% 15% 28% 10% 2	3733
	11th to 20th	Night	41% 6% 11% 25% 16% 1	3717
	21st to end	Night	54% 7% 9% 19% 10% 2	3466
April	1st to 10th	Night	50% 6% 8% 17% 18% 1	1900
	11th to 20th	Night	47% 4 9% 22% 14% 3	1875
	21st to end	Night	47% 6% 10% 21% 14% 2	1755
May	1st to 10th	Night	42% 7% 14% 19% 17% 1	2748
	11th to 20th	Night	37% 8% 11% 28% 14% 2	2507
	21st to end	Night	44% 7% 11% 18% 15% 6%	2751
June	1st to 10th	Night	35% 7% 12% 30% 16% 1	1520
	11th to 20th	Night	36% 7% 11% 27% 18% 2	1520
	21st to end	Night	30% 10% 17% 25% 15% 3	1520
July	1st to 10th	Night	40% 5% 16% 22% 12% 6%	2490
	11th to 20th	Night	23% 7% 17% 33% 17% 2	2482
	21st to end	Night	29% 8% 14% 24% 23% 2	2662
August	1st to 10th	Night	34% 6% 13% 27% 18% 2	2508
	11th to 20th	Night	35% 6% 12% 31% 16% 1	2955
	21st to end	Night	32% 6% 15% 23% 21% 3	3476
September	1st to 10th	Night	31% 6% 12% 27% 23% 2	1900
	11th to 20th	Night	32% 5% 12% 34% 16% 1	1984
	21st to end	Night	37% 5% 13% 29% 16% 1	2090
October	1st to 10th	Night	27% 4 8% 38% 21% 2	3630
	11th to 20th	Night	34% 5% 13% 30% 15% 2	3855
	21st to end	Night	45% 5% 11% 24% 16%	4467
November	1st to 10th	Night	41% 5% 13% 25% 15% 2	2483
	11th to 20th	Night	53% 5% 13% 18% 10% 1	2470
	21st to end	Night	49% 5% 16% 24% 6% 1	2650
December	1st to 10th	Night	55% 6% 14% 19% 6% 1	2660
	11th to 20th	Night	58% 6% 11% 17% 8% 1	3281
	21st to end	Night	66% 7% 9% 14% 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	16% 14% 34% 26% 8% 1	270
	11th to 20th	Day	18% 13% 36% 27% 5% 1	270
	21st to end	Day	19% 12% 33% 28% 7% 1	297
February	1st to 10th	Day	13% 16% 41% 21% 8% 1	270
	11th to 20th	Day	14% 20% 40% 17% 8%	270
	21st to end	Day	18% 17% 47% 16% 2	225
March	1st to 10th	Day	16% 16% 44% 19% 6%	270
	11th to 20th	Day	23% 14% 31% 22% 7% 2	285
	21st to end	Day	25% 13% 29% 24% 8% 1	506
April	1st to 10th	Day	25% 13% 33% 22% 6%	460
	11th to 20th	Day	26% 17% 29% 18% 9% 2	452
	21st to end	Day	20% 14% 27% 25% 11% 3	460
May	1st to 10th	Day	20% 11% 33% 25% 10% 2	515
	11th to 20th	Day	16% 11% 32% 28% 9% 3	675
	21st to end	Day	16% 9% 29% 26% 15% 5%	734
June	1st to 10th	Day	11% 10% 32% 30% 14% 4	680
	11th to 20th	Day	16% 7% 33% 28% 13% 3	680
	21st to end	Day	14% 8% 29% 30% 15% 3	680
July	1st to 10th	Day	10% 4 21% 32% 24% 8%	671
	11th to 20th	Day	9% 6% 26% 32% 19% 7%	668
	21st to end	Day	8% 4 26% 32% 22% 8%	739
August	1st to 10th	Day	8% 4 27% 33% 21% 8%	676
	11th to 20th	Day	11% 4 19% 28% 26% 11%	506
	21st to end	Day	16% 6% 20% 30% 20% 9%	539
September	1st to 10th	Day	15% 8% 22% 27% 20% 8%	490
	11th to 20th	Day	11% 4 21% 37% 18% 9%	490
	21st to end	Day	15% 10% 26% 28% 17% 5%	490
October	1st to 10th	Day	18% 12% 24% 26% 17% 3	400
	11th to 20th	Day	19% 18% 30% 24% 8%	300
	21st to end	Day	24% 13% 39% 17% 5% 1	330
November	1st to 10th	Day	17% 15% 34% 23% 9% 1	285
	11th to 20th	Day	17% 16% 41% 18% 9%	270
	21st to end	Day	21% 16% 42% 14% 7%	270
December	1st to 10th	Day	19% 15% 43% 19% 5%	270
	11th to 20th	Day	22% 14% 41% 16% 5% 2	270
	21st to end	Day	26% 13% 39% 16% 5%	297
January	1st to 10th	Night	16% 14% 38% 26% 6%	950
	11th to 20th	Night	20% 11% 37% 24% 6% 1	950
	21st to end	Night	20% 8% 37% 28% 7%	1045
February	1st to 10th	Night	17% 13% 37% 27% 6%	950
	11th to 20th	Night	15% 14% 38% 25% 7%	777
	21st to end	Night	22% 12% 35% 26% 4	628
March	1st to 10th	Night	20% 10% 34% 27% 8% 1	760
	11th to 20th	Night	16% 11% 37% 30% 6% 1	732
	21st to end	Night	21% 6% 32% 31% 10%	627
April	1st to 10th	Night	22% 9% 38% 26% 5%	570
	11th to 20th	Night	23% 11% 31% 27% 7% 1	563
	21st to end	Night	20% 8% 33% 31% 8% 1	570
May	1st to 10th	Night	21% 8% 33% 31% 7%	570
	11th to 20th	Night	19% 6% 36% 30% 9%	561
	21st to end	Night	14% 6% 27% 38% 15% 1	617
June	1st to 10th	Night	9% 6% 31% 40% 13% 1	570
	11th to 20th	Night	15% 5% 31% 37% 12% 1	570
	21st to end	Night	10% 3 28% 43% 15% 1	570
July	1st to 10th	Night	9% 2 21% 45% 22% 2	555
	11th to 20th	Night	9% 3 23% 40% 23% 2	552
	21st to end	Night	6% 2 21% 46% 24% 1	624
August	1st to 10th	Night	9% 2 16% 45% 25% 2	567
	11th to 20th	Night	10% 2 18% 40% 26% 4	564
	21st to end	Night	10% 3 22% 40% 23% 2	627
September	1st to 10th	Night	11% 4 24% 36% 20% 5%	570
	11th to 20th	Night	14% 4 21% 34% 21% 4	654
	21st to end	Night	14% 8% 26% 31% 19% 2	760
October	1st to 10th	Night	15% 8% 28% 31% 16% 1	760
	11th to 20th	Night	19% 12% 34% 27% 8%	760
	21st to end	Night	24% 10% 31% 25% 9% 1	836
November	1st to 10th	Night	17% 9% 39% 26% 8% 1	764
	11th to 20th	Night	20% 16% 36% 23% 5%	760
	21st to end	Night	20% 14% 36% 22% 7%	940
December	1st to 10th	Night	21% 14% 39% 20% 6%	950
	11th to 20th	Night	22% 13% 37% 22% 5% 1	950
	21st to end	Night	25% 14% 36% 22% 3	1045

Page generated at 2024-11-03 12:19:06. Version ac07

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