Weinberg-King State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Weinberg-King State Park clear sky chart from 2005-11-06 to 2025-09-19.

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% 8% 3 7% 5% 4 4 4 5% 7% 40%	126535
	Night	13% 8% 3 7% 4 4 4 3 5% 6% 41%	122785
Transparency	Day	42% 6% 12% 23% 15% 2	130099
	Night	42% 5% 12% 23% 16% 2	127297
Seeing	Day	15% 11% 28% 27% 15% 4	16976
	Night	16% 10% 31% 30% 12% 1	26721

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	12% 11% 6% 15% 7% 5% 4 3 5% 6% 27%	3617
	11th to 20th	Day	9% 9% 4 10% 6% 6% 7% 3 6% 6% 33%	3822
	21st to end	Day	16% 15% 7% 10% 6% 4 3 2 3 4 29%	4488
February	1st to 10th	Day	15% 10% 5% 10% 6% 5% 5% 4 5% 6% 31%	1800
	11th to 20th	Day	13% 10% 3 8% 6% 6% 4 4 5% 7% 34%	1861
	21st to end	Day	14% 11% 4 9% 5% 4 3 3 4 6% 38%	1650
March	1st to 10th	Day	17% 11% 3 6% 3 3 3 2 4 4 45%	4606
	11th to 20th	Day	8% 7% 2 5% 4 4 5% 4 6% 9% 47%	4980
	21st to end	Day	18% 10% 3 8% 5% 4 4 3 5% 7% 32%	5727
April	1st to 10th	Day	15% 10% 3 7% 4 4 4 3 6% 6% 37%	2400
	11th to 20th	Day	15% 9% 2 7% 5% 5% 4 3 5% 6% 39%	2374
	21st to end	Day	19% 7% 3 8% 5% 5% 4 4 5% 7% 34%	2400
May	1st to 10th	Day	14% 7% 3 8% 5% 4 5% 4 6% 9% 35%	5791
	11th to 20th	Day	14% 7% 2 6% 4 4 4 3 5% 7% 44%	6319
	21st to end	Day	14% 7% 3 7% 5% 5% 5% 4 5% 7% 39%	6935
June	1st to 10th	Day	8% 5% 2 6% 5% 4 5% 4 6% 9% 46%	2800
	11th to 20th	Day	7% 5% 3 7% 5% 5% 5% 4 6% 7% 47%	2800
	21st to end	Day	9% 5% 2 6% 5% 4 5% 5% 7% 8% 44%	2800
July	1st to 10th	Day	10% 5% 2 6% 5% 4 5% 4 7% 9% 43%	6360
	11th to 20th	Day	10% 6% 2 7% 5% 5% 5% 4 7% 10% 39%	6360
	21st to end	Day	11% 5% 2 7% 5% 5% 5% 5% 8% 10% 38%	6700
August	1st to 10th	Day	6% 4 2 5% 4 4 5% 5% 6% 10% 47%	4234
	11th to 20th	Day	12% 5% 2 6% 4 5% 4 4 6% 10% 43%	3950
	21st to end	Day	6% 4 2 6% 4 4 5% 4 6% 9% 51%	4312
September	1st to 10th	Day	12% 4 1 5% 4 3 4 4 5% 7% 51%	2400
	11th to 20th	Day	9% 4 2 5% 3 4 4 3 5% 9% 53%	2375
	21st to end	Day	8% 5% 2 5% 4 4 4 5% 5% 8% 50%	2040
October	1st to 10th	Day	12% 4 2 6% 4 4 3 3 5% 5% 52%	1900
	11th to 20th	Day	14% 8% 3 7% 4 3 3 2 4 5% 47%	1900
	21st to end	Day	18% 8% 3 7% 3 3 4 3 4 5% 42%	2057
November	1st to 10th	Day	10% 8% 2 6% 4 3 3 3 5% 6% 49%	1762
	11th to 20th	Day	15% 9% 4 6% 3 3 4 2 5% 6% 43%	1800
	21st to end	Day	17% 11% 3 8% 4 3 3 2 3 7% 37%	1615
December	1st to 10th	Day	8% 8% 3 7% 4 4 3 2 4 6% 50%	2610
	11th to 20th	Day	14% 11% 5% 12% 4 4 4 3 5% 6% 31%	3008
	21st to end	Day	23% 22% 7% 11% 3 3 3 3 3 4 17%	3982
January	1st to 10th	Night	13% 12% 7% 12% 5% 4 4 3 4 5% 31%	6348
	11th to 20th	Night	12% 13% 5% 12% 6% 4 6% 4 5% 3 29%	6157
	21st to end	Night	16% 14% 5% 10% 4 4 3 2 4 5% 31%	6490
February	1st to 10th	Night	15% 12% 5% 8% 5% 5% 4 4 5% 6% 34%	2600
	11th to 20th	Night	15% 9% 4 7% 5% 4 3 3 5% 8% 38%	2425
	21st to end	Night	15% 10% 4 7% 4 4 3 3 4 4 44%	1980
March	1st to 10th	Night	18% 11% 4 5% 3 3 3 2 4 5% 41%	5291
	11th to 20th	Night	11% 7% 2 5% 3 3 3 3 4 6% 51%	4980
	21st to end	Night	17% 11% 3 8% 5% 4 5% 4 5% 7% 32%	5202
April	1st to 10th	Night	13% 7% 3 7% 5% 4 4 4 5% 7% 42%	2000
	11th to 20th	Night	13% 8% 2 6% 4 4 4 4 5% 7% 43%	1975
	21st to end	Night	18% 8% 2 7% 4 4 4 5% 4 5% 40%	2000
May	1st to 10th	Night	19% 8% 2 7% 4 4 4 3 5% 7% 36%	4096
	11th to 20th	Night	13% 5% 2 5% 4 5% 4 4 6% 8% 45%	3596
	21st to end	Night	13% 6% 3 6% 4 4 4 3 5% 7% 45%	3942
June	1st to 10th	Night	8% 5% 2 4 3 4 4 3 6% 9% 52%	1600
	11th to 20th	Night	8% 5% 2 6% 5% 4 4 3 6% 9% 50%	1600
	21st to end	Night	7% 4 2 5% 5% 5% 4 5% 6% 7% 49%	1600
July	1st to 10th	Night	10% 5% 2 6% 4 4 4 3 6% 10% 45%	3618
	11th to 20th	Night	6% 4 2 6% 5% 5% 5% 4 6% 8% 49%	3617
	21st to end	Night	12% 5% 2 6% 4 4 5% 3 6% 10% 43%	4167
August	1st to 10th	Night	5% 3 1 4 3 3 4 4 6% 10% 57%	2926
	11th to 20th	Night	8% 5% 2 5% 4 4 4 3 5% 7% 53%	3100
	21st to end	Night	5% 3 2 4 4 4 5% 4 6% 9% 55%	3586
September	1st to 10th	Night	10% 5% 2 5% 3 3 3 2 4 6% 58%	2000
	11th to 20th	Night	7% 5% 1 5% 4 3 4 4 5% 8% 54%	1980
	21st to end	Night	8% 4 2 6% 4 5% 4 4 5% 7% 51%	2118
October	1st to 10th	Night	10% 4 1 4 4 3 4 3 4 7% 56%	2280
	11th to 20th	Night	14% 4 2 5% 3 3 3 3 4 5% 53%	2280
	21st to end	Night	17% 8% 2 5% 4 4 4 4 4 5% 44%	2539
November	1st to 10th	Night	12% 6% 2 4 3 3 4 3 4 5% 54%	2536
	11th to 20th	Night	14% 7% 2 6% 4 4 3 3 5% 6% 45%	2600
	21st to end	Night	16% 10% 3 8% 4 3 3 3 4 6% 40%	2781
December	1st to 10th	Night	9% 9% 2 7% 5% 3 3 3 4 6% 47%	4580
	11th to 20th	Night	15% 9% 3 10% 5% 4 4 3 4 6% 36%	5199
	21st to end	Night	24% 18% 6% 10% 5% 5% 3 3 4 4 19%	6996

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	58% 4 12% 16% 9% 1	3618
	11th to 20th	Day	51% 4 14% 15% 13% 4	3822
	21st to end	Day	60% 4 8% 18% 8% 1	4488
February	1st to 10th	Day	53% 6% 14% 18% 7% 2	1800
	11th to 20th	Day	49% 6% 11% 20% 12% 1	1870
	21st to end	Day	48% 5% 12% 22% 12% 2	1650
March	1st to 10th	Day	44% 3 8% 23% 19% 2	4606
	11th to 20th	Day	33% 5% 11% 30% 20% 1	4980
	21st to end	Day	51% 6% 14% 22% 5% 1	5729
April	1st to 10th	Day	45% 6% 12% 24% 12%	2400
	11th to 20th	Day	45% 5% 10% 24% 14% 2	2374
	21st to end	Day	48% 7% 12% 19% 13% 2	2400
May	1st to 10th	Day	44% 8% 13% 19% 15% 1	5826
	11th to 20th	Day	40% 6% 12% 26% 13% 3	6323
	21st to end	Day	44% 7% 10% 22% 17% 1	6949
June	1st to 10th	Day	33% 8% 15% 28% 15% 2	2800
	11th to 20th	Day	35% 7% 11% 24% 20% 3	2800
	21st to end	Day	35% 8% 15% 22% 17% 3	2800
July	1st to 10th	Day	36% 6% 13% 27% 16% 2	6291
	11th to 20th	Day	39% 7% 15% 24% 14% 1	6285
	21st to end	Day	38% 8% 19% 24% 10%	6509
August	1st to 10th	Day	30% 7% 18% 33% 11% 1	4220
	11th to 20th	Day	37% 7% 14% 28% 13% 1	3988
	21st to end	Day	29% 7% 15% 30% 15% 4	4311
September	1st to 10th	Day	32% 6% 10% 27% 20% 5%	2400
	11th to 20th	Day	29% 5% 11% 30% 21% 4	2375
	21st to end	Day	31% 7% 11% 28% 21% 2	2040
October	1st to 10th	Day	24% 3 6% 16% 47% 4	3160
	11th to 20th	Day	27% 2 7% 23% 35% 6%	3140
	21st to end	Day	41% 3 8% 25% 20% 2	3371
November	1st to 10th	Day	36% 4 14% 24% 19% 3	1762
	11th to 20th	Day	43% 3 11% 24% 15% 3	1800
	21st to end	Day	50% 4 13% 22% 10%	1615
December	1st to 10th	Day	37% 4 16% 32% 11%	2610
	11th to 20th	Day	54% 5% 10% 20% 9% 1	3005
	21st to end	Day	71% 4 11% 10% 4	3982
January	1st to 10th	Night	55% 5% 13% 20% 7%	6348
	11th to 20th	Night	59% 3 9% 15% 12% 2	6157
	21st to end	Night	56% 3 9% 19% 12% 1	6490
February	1st to 10th	Night	52% 4 12% 19% 11% 2	2600
	11th to 20th	Night	47% 3 12% 24% 13% 1	2426
	21st to end	Night	44% 4 9% 24% 16% 3	1980
March	1st to 10th	Night	47% 4 7% 22% 18% 2	5291
	11th to 20th	Night	35% 4 7% 28% 20% 5%	4980
	21st to end	Night	51% 6% 14% 20% 7% 2	5202
April	1st to 10th	Night	41% 5% 12% 25% 15% 3	2000
	11th to 20th	Night	40% 6% 10% 25% 15% 4	1975
	21st to end	Night	45% 6% 11% 20% 15% 3	2000
May	1st to 10th	Night	46% 7% 11% 23% 11% 2	4126
	11th to 20th	Night	35% 7% 15% 26% 13% 4	3597
	21st to end	Night	38% 6% 13% 22% 20% 2	3950
June	1st to 10th	Night	28% 6% 17% 28% 18% 3	1600
	11th to 20th	Night	31% 6% 12% 25% 22% 4	1600
	21st to end	Night	31% 10% 15% 21% 20% 3	1600
July	1st to 10th	Night	35% 5% 13% 29% 16% 2	3580
	11th to 20th	Night	32% 7% 13% 28% 19% 1	3572
	21st to end	Night	35% 7% 17% 25% 15% 1	4047
August	1st to 10th	Night	22% 7% 19% 33% 18% 1	2916
	11th to 20th	Night	31% 5% 14% 31% 18% 1	3128
	21st to end	Night	26% 7% 17% 30% 17% 4	3586
September	1st to 10th	Night	27% 4 12% 26% 24% 7%	2000
	11th to 20th	Night	27% 6% 11% 25% 25% 5%	1980
	21st to end	Night	31% 5% 11% 25% 25% 3	2118
October	1st to 10th	Night	21% 3 7% 22% 43% 4	3800
	11th to 20th	Night	25% 3 9% 21% 37% 5%	3779
	21st to end	Night	39% 4 8% 21% 24% 4	4175
November	1st to 10th	Night	33% 5% 13% 25% 20% 5%	2536
	11th to 20th	Night	40% 4 12% 23% 19% 2	2600
	21st to end	Night	47% 3 11% 25% 13% 1	2781
December	1st to 10th	Night	39% 4 12% 33% 12% 1	4580
	11th to 20th	Night	50% 4 12% 22% 11%	5201
	21st to end	Night	69% 5% 10% 11% 4 1	6996

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	21% 17% 35% 18% 9%	300
	11th to 20th	Day	23% 24% 36% 15% 2	300
	21st to end	Day	18% 22% 40% 15% 6%	330
February	1st to 10th	Day	25% 16% 37% 18% 5%	300
	11th to 20th	Day	21% 23% 31% 18% 5% 1	300
	21st to end	Day	23% 16% 41% 17% 2	249
March	1st to 10th	Day	20% 23% 39% 15% 2	300
	11th to 20th	Day	24% 18% 35% 17% 6%	300
	21st to end	Day	33% 17% 31% 15% 3 1	440
April	1st to 10th	Day	22% 16% 34% 22% 6% 1	500
	11th to 20th	Day	21% 17% 33% 19% 10% 1	492
	21st to end	Day	21% 13% 38% 21% 7% 1	500
May	1st to 10th	Day	19% 11% 34% 27% 7% 2	583
	11th to 20th	Day	18% 13% 27% 26% 14% 2	725
	21st to end	Day	16% 7% 32% 25% 14% 6%	789
June	1st to 10th	Day	9% 5% 24% 34% 22% 6%	730
	11th to 20th	Day	8% 5% 27% 34% 21% 5%	730
	21st to end	Day	8% 9% 29% 33% 16% 4	730
July	1st to 10th	Day	9% 4 17% 31% 25% 14%	721
	11th to 20th	Day	8% 3 24% 36% 24% 6%	718
	21st to end	Day	10% 2 18% 35% 30% 5%	794
August	1st to 10th	Day	7% 3 17% 42% 23% 8%	726
	11th to 20th	Day	9% 4 19% 27% 31% 10%	584
	21st to end	Day	7% 3 16% 31% 32% 11%	583
September	1st to 10th	Day	12% 5% 16% 32% 27% 8%	530
	11th to 20th	Day	7% 2 16% 36% 27% 11%	522
	21st to end	Day	10% 9% 23% 29% 20% 9%	440
October	1st to 10th	Day	13% 11% 26% 30% 14% 6%	300
	11th to 20th	Day	15% 19% 35% 21% 9% 1	300
	21st to end	Day	28% 14% 34% 20% 4	330
November	1st to 10th	Day	12% 14% 39% 22% 10% 3	300
	11th to 20th	Day	20% 19% 29% 25% 6% 2	300
	21st to end	Day	26% 14% 32% 21% 7%	300
December	1st to 10th	Day	13% 19% 39% 20% 6% 3	300
	11th to 20th	Day	20% 18% 36% 21% 5%	300
	21st to end	Day	27% 21% 37% 13% 2	330
January	1st to 10th	Night	17% 15% 41% 21% 6%	1000
	11th to 20th	Night	19% 17% 38% 21% 5%	1000
	21st to end	Night	19% 15% 38% 26% 3	1100
February	1st to 10th	Night	20% 14% 40% 23% 4	1000
	11th to 20th	Night	20% 15% 37% 24% 3	870
	21st to end	Night	21% 17% 39% 21% 2	660
March	1st to 10th	Night	18% 15% 41% 22% 4	770
	11th to 20th	Night	20% 13% 34% 28% 5%	600
	21st to end	Night	25% 13% 36% 22% 5% 1	660
April	1st to 10th	Night	18% 16% 37% 26% 4	600
	11th to 20th	Night	18% 12% 34% 30% 6% 1	593
	21st to end	Night	21% 10% 36% 27% 6%	600
May	1st to 10th	Night	18% 6% 38% 30% 8% 1	600
	11th to 20th	Night	16% 7% 29% 35% 12% 1	591
	21st to end	Night	12% 7% 26% 35% 18% 2	650
June	1st to 10th	Night	9% 4 24% 43% 19% 1	600
	11th to 20th	Night	10% 4 25% 43% 18% 2	600
	21st to end	Night	7% 5% 29% 39% 20% 1	600
July	1st to 10th	Night	10% 2 12% 39% 32% 4	585
	11th to 20th	Night	5% 3 16% 45% 29% 1	582
	21st to end	Night	8% 2 12% 44% 32% 1	657
August	1st to 10th	Night	6% 3 13% 47% 29% 3	597
	11th to 20th	Night	6% 2 15% 41% 31% 5%	594
	21st to end	Night	6% 1 12% 42% 37% 2	660
September	1st to 10th	Night	11% 3 17% 38% 27% 4	600
	11th to 20th	Night	9% 2 17% 36% 31% 4	594
	21st to end	Night	9% 7% 23% 34% 23% 4	741
October	1st to 10th	Night	10% 6% 28% 32% 21% 3	760
	11th to 20th	Night	17% 11% 33% 28% 11% 1	760
	21st to end	Night	20% 14% 34% 26% 6%	836
November	1st to 10th	Night	15% 11% 37% 29% 8% 1	780
	11th to 20th	Night	17% 15% 38% 25% 6%	800
	21st to end	Night	22% 13% 36% 24% 5%	981
December	1st to 10th	Night	19% 13% 39% 24% 5% 1	1000
	11th to 20th	Night	22% 12% 33% 27% 6%	1000
	21st to end	Night	26% 17% 33% 22% 2	1100

Page generated at 2025-09-16 00:49:12. Version ac07

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