Falcon State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Falcon State Park clear sky chart from 2005-11-06 to 2025-12-18.

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
Transparency	Day	14% 56% 6% 12% 7% 5%	130824
	Night	15% 57% 6% 10% 7% 5%	128549
Seeing	Day	9% 3 12% 32% 29% 14%	15753
	Night	12% 4 25% 43% 15% 1	25810

By Month

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	27% 42% 4 11% 10% 6%	4078
	11th to 20th	Day	22% 41% 4 15% 14% 5%	4511
	21st to end	Day	28% 42% 5% 11% 9% 4	4994
February	1st to 10th	Day	2 90% 1 1 2 3	2000
	11th to 20th	Day	6% 90% 1 1 2 1	1959
	21st to end	Day	3 90% 1 3 2 2	1650
March	1st to 10th	Day	16% 44% 6% 13% 6% 16%	4803
	11th to 20th	Day	21% 41% 2 3 13% 20%	4980
	21st to end	Day	15% 41% 5% 18% 12% 9%	5464
April	1st to 10th	Day	2 90% 1 2 4	2200
	11th to 20th	Day	4 91% 1 2 1 2	2181
	21st to end	Day	4 91% 2 2 1	2400
May	1st to 10th	Day	25% 44% 9% 14% 6% 2	5803
	11th to 20th	Day	9% 44% 12% 13% 12% 10%	5866
	21st to end	Day	15% 43% 7% 30% 4	6447
June	1st to 10th	Day	1 90% 1 6% 1	2600
	11th to 20th	Day	2 90% 1 1 5% 1	2600
	21st to end	Day	4 90% 2 3 2	2600
July	1st to 10th	Day	24% 42% 15% 18% 2	5836
	11th to 20th	Day	20% 41% 19% 17% 3	5831
	21st to end	Day	18% 41% 13% 21% 7%	5854
August	1st to 10th	Day	1 52% 4 25% 16%	3892
	11th to 20th	Day	9% 55% 16% 19% 2	3882
	21st to end	Day	7% 56% 12% 16% 9% 1	4151
September	1st to 10th	Day	4 86% 1 3 4 2	2200
	11th to 20th	Day	5% 86% 2 5% 2	2200
	21st to end	Day	1 85% 2 7% 3 2	2200
October	1st to 10th	Day	8% 53% 2 1 14% 22%	3590
	11th to 20th	Day	11% 54% 3 7% 9% 16%	3568
	21st to end	Day	6% 54% 3 9% 22% 6%	3545
November	1st to 10th	Day	4 86% 1 3 3 3	2058
	11th to 20th	Day	3 86% 2 4 2 2	2021
	21st to end	Day	8% 86% 1 2 2 1	1890
December	1st to 10th	Day	33% 55% 3 3 4 2	3030
	11th to 20th	Day	18% 52% 7% 10% 6% 6%	3452
	21st to end	Day	19% 43% 2 13% 14% 9%	4488
January	1st to 10th	Night	26% 41% 3 10% 11% 8%	5888
	11th to 20th	Night	19% 41% 5% 12% 15% 7%	5512
	21st to end	Night	34% 42% 4 10% 9% 2	5984
February	1st to 10th	Night	3 90% 1 1 3 3	2400
	11th to 20th	Night	5% 90% 1 1 2 1	2338
	21st to end	Night	3 90% 3 2 1	1980
March	1st to 10th	Night	16% 44% 5% 17% 5% 12%	5056
	11th to 20th	Night	21% 43% 3 3 13% 17%	4980
	21st to end	Night	15% 42% 5% 15% 16% 7%	5467
April	1st to 10th	Night	3 91% 1 2 2 3	2200
	11th to 20th	Night	3 90% 1 1 1 2	2163
	21st to end	Night	5% 90% 2 1 1	2000
May	1st to 10th	Night	26% 44% 10% 14% 4 2	4171
	11th to 20th	Night	10% 43% 10% 16% 13% 8%	4054
	21st to end	Night	23% 43% 10% 21% 3	4452
June	1st to 10th	Night	2 91% 2 5% 1	1800
	11th to 20th	Night	2 90% 1 2 5%	1800
	21st to end	Night	3 90% 3 3 1	1800
July	1st to 10th	Night	26% 42% 16% 16% 1	4035
	11th to 20th	Night	22% 41% 20% 15% 2	4026
	21st to end	Night	20% 41% 15% 18% 6%	4673
August	1st to 10th	Night	52% 8% 30% 9%	3244
	11th to 20th	Night	11% 55% 20% 12% 1	3243
	21st to end	Night	6% 55% 14% 19% 5%	3750
September	1st to 10th	Night	4 86% 1 3 5% 1	2200
	11th to 20th	Night	5% 86% 3 5% 2	2200
	21st to end	Night	2 86% 2 6% 2 1	2200
October	1st to 10th	Night	10% 53% 2 2 11% 22%	3590
	11th to 20th	Night	10% 54% 3 5% 15% 13%	3570
	21st to end	Night	9% 55% 3 10% 18% 5%	4210
November	1st to 10th	Night	5% 86% 1 3 2 3	2460
	11th to 20th	Night	3 86% 2 4 3 2	2594
	21st to end	Night	7% 86% 2 2 2 1	2730
December	1st to 10th	Night	38% 55% 2 4 1	4380
	11th to 20th	Night	15% 50% 7% 15% 6% 7%	4909
	21st to end	Night	19% 44% 3 10% 12% 12%	6490

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% 7% 19% 33% 16% 5%	300
	11th to 20th	Day	17% 7% 18% 36% 20% 3	300
	21st to end	Day	22% 6% 19% 35% 17% 2	330
February	1st to 10th	Day	16% 4 24% 27% 21% 7%	300
	11th to 20th	Day	22% 5% 22% 32% 17% 3	300
	21st to end	Day	13% 6% 16% 47% 16% 2	249
March	1st to 10th	Day	16% 8% 19% 41% 14% 3	300
	11th to 20th	Day	17% 5% 19% 41% 18% 1	300
	21st to end	Day	10% 3 25% 43% 18% 1	330
April	1st to 10th	Day	13% 5% 16% 48% 17%	300
	11th to 20th	Day	10% 5% 21% 38% 22% 4	299
	21st to end	Day	8% 6% 31% 39% 14% 2	500
May	1st to 10th	Day	9% 4 26% 40% 17% 3	658
	11th to 20th	Day	11% 2 23% 42% 18% 4	725
	21st to end	Day	5% 2 19% 45% 25% 4	789
June	1st to 10th	Day	2 1 8% 40% 39% 11%	730
	11th to 20th	Day	4 1 8% 47% 32% 8%	730
	21st to end	Day	5% 2 7% 35% 36% 14%	730
July	1st to 10th	Day	6% 1 6% 35% 36% 16%	721
	11th to 20th	Day	2 1 4 32% 45% 15%	718
	21st to end	Day	4 1 4 30% 39% 22%	628
August	1st to 10th	Day	1 2 28% 41% 27%	527
	11th to 20th	Day	2 1 2 25% 37% 33%	517
	21st to end	Day	2 1 4 15% 34% 43%	488
September	1st to 10th	Day	8% 2 4 11% 35% 41%	330
	11th to 20th	Day	6% 2 2 7% 30% 53%	330
	21st to end	Day	5% 1 3 11% 39% 41%	330
October	1st to 10th	Day	8% 2 3 11% 38% 38%	330
	11th to 20th	Day	10% 1 3 17% 40% 29%	330
	21st to end	Day	9% 3 12% 31% 28% 17%	363
November	1st to 10th	Day	10% 3 8% 23% 41% 14%	330
	11th to 20th	Day	19% 4 9% 21% 32% 15%	330
	21st to end	Day	24% 5% 15% 26% 23% 8%	330
December	1st to 10th	Day	19% 5% 15% 28% 22% 12%	330
	11th to 20th	Day	19% 5% 17% 31% 22% 7%	321
	21st to end	Day	18% 3 14% 31% 26% 8%	330
January	1st to 10th	Night	20% 5% 19% 41% 15% 1	1000
	11th to 20th	Night	18% 5% 25% 44% 8%	833
	21st to end	Night	20% 5% 28% 37% 8%	880
February	1st to 10th	Night	16% 6% 31% 39% 7% 1	800
	11th to 20th	Night	18% 7% 37% 32% 7%	784
	21st to end	Night	15% 5% 38% 37% 5%	660
March	1st to 10th	Night	12% 7% 43% 34% 4 1	664
	11th to 20th	Night	10% 10% 45% 32% 3	600
	21st to end	Night	11% 6% 48% 33% 2	660
April	1st to 10th	Night	10% 7% 45% 35% 3	600
	11th to 20th	Night	10% 7% 46% 34% 3	593
	21st to end	Night	10% 7% 50% 29% 4	600
May	1st to 10th	Night	11% 5% 50% 31% 3	600
	11th to 20th	Night	9% 5% 46% 35% 5%	591
	21st to end	Night	5% 3 42% 43% 6%	650
June	1st to 10th	Night	3 2 20% 62% 13%	600
	11th to 20th	Night	4 1 26% 62% 8%	600
	21st to end	Night	5% 1 20% 54% 19% 1	600
July	1st to 10th	Night	8% 1 14% 59% 17% 1	585
	11th to 20th	Night	2 1 14% 66% 16% 1	582
	21st to end	Night	4 1 11% 65% 19% 1	657
August	1st to 10th	Night	1 1 10% 64% 22% 1	597
	11th to 20th	Night	3 1 7% 65% 23% 2	594
	21st to end	Night	6% 1 6% 50% 34% 5%	660
September	1st to 10th	Night	9% 1 6% 44% 34% 7%	600
	11th to 20th	Night	10% 2 4 38% 41% 6%	600
	21st to end	Night	7% 1 8% 41% 38% 5%	600
October	1st to 10th	Night	5% 2 8% 47% 36% 3	600
	11th to 20th	Night	12% 2 11% 48% 25% 3	600
	21st to end	Night	8% 3 22% 46% 19% 2	850
November	1st to 10th	Night	10% 3 17% 46% 21% 2	820
	11th to 20th	Night	16% 3 21% 39% 21% 2	914
	21st to end	Night	18% 5% 22% 39% 16% 1	1050
December	1st to 10th	Night	20% 3 19% 39% 17% 2	1050
	11th to 20th	Night	23% 4 21% 36% 15% 1	1036
	21st to end	Night	16% 4 22% 40% 17% 1	1100

Page generated at 2025-12-15 00:13:49. Version ac07

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