Lake Colorado City State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Colorado City State Park clear sky chart from 2005-11-06 to 2026-08-15.

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	6% 4 1 4 3 3 3 3 5% 7% 61%	152229
	Night	6% 4 1 4 3 3 3 3 5% 7% 63%	147132
Transparency	Day	24% 4 8% 22% 27% 15%	147320
	Night	22% 3 8% 22% 27% 18%	143053
Seeing	Day	8% 5% 21% 32% 26% 9%	17453
	Night	8% 5% 29% 42% 16% 1	27323

By Month

Percentage Cloud Cover SW (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	7% 5% 2 4 3 3 3 3 4 6% 61%	5287
	11th to 20th	Day	3 2 1 2 2 2 3 2 4 6% 73%	5527
	21st to end	Day	10% 6% 2 5% 3 3 3 3 5% 6% 52%	6468
February	1st to 10th	Day	8% 5% 2 4 2 2 3 3 4 6% 62%	2100
	11th to 20th	Day	7% 5% 2 6% 3 3 3 3 4 6% 57%	2049
	21st to end	Day	8% 7% 2 3 2 2 2 2 3 4 64%	1730
March	1st to 10th	Day	5% 4 1 4 3 3 3 3 4 6% 63%	4600
	11th to 20th	Day	10% 5% 1 4 2 3 3 3 5% 6% 58%	5017
	21st to end	Day	3 4 1 4 4 4 4 3 5% 6% 61%	5585
April	1st to 10th	Day	7% 4 1 3 3 3 3 4 5% 6% 61%	2513
	11th to 20th	Day	9% 4 2 6% 3 3 3 3 4 5% 59%	2491
	21st to end	Day	6% 4 1 3 3 2 3 3 4 6% 63%	2520
May	1st to 10th	Day	10% 6% 2 5% 3 3 4 3 5% 7% 52%	7631
	11th to 20th	Day	10% 4 1 4 3 3 3 3 5% 6% 57%	7627
	21st to end	Day	9% 5% 2 6% 4 4 4 4 5% 7% 50%	8404
June	1st to 10th	Day	3 3 1 4 3 3 4 3 5% 8% 64%	2730
	11th to 20th	Day	4 2 1 3 3 3 4 3 6% 8% 64%	2730
	21st to end	Day	4 3 1 3 4 3 4 4 5% 8% 63%	2730
July	1st to 10th	Day	7% 4 1 5% 3 3 4 4 5% 8% 55%	7679
	11th to 20th	Day	6% 4 1 5% 4 4 4 4 6% 9% 55%	7680
	21st to end	Day	2 1 1 2 2 2 3 3 5% 8% 71%	8225
August	1st to 10th	Day	1 1 2 2 2 3 3 4 7% 74%	5468
	11th to 20th	Day	2 2 1 4 3 4 5% 4 8% 11% 58%	5415
	21st to end	Day	3 2 1 4 3 4 4 4 6% 8% 60%	5984
September	1st to 10th	Day	9% 5% 2 4 3 4 4 4 5% 7% 53%	2308
	11th to 20th	Day	9% 5% 2 5% 3 4 4 4 6% 9% 49%	2200
	21st to end	Day	9% 4 1 4 3 3 3 3 4 6% 60%	2200
October	1st to 10th	Day	3 2 1 2 2 2 2 2 3 4 78%	3590
	11th to 20th	Day	9% 4 1 3 2 2 2 2 2 4 68%	3568
	21st to end	Day	6% 3 1 2 2 2 1 1 3 3 77%	3442
November	1st to 10th	Day	7% 4 1 3 2 2 3 2 4 5% 66%	1853
	11th to 20th	Day	5% 3 1 4 3 2 3 2 4 6% 67%	1890
	21st to end	Day	10% 5% 1 3 2 3 2 3 4 6% 60%	1890
December	1st to 10th	Day	10% 7% 2 6% 3 3 3 3 4 6% 53%	3030
	11th to 20th	Day	5% 3 2 4 4 3 3 3 4 5% 64%	3481
	21st to end	Day	7% 4 1 3 2 2 2 1 2 4 71%	4587
January	1st to 10th	Night	6% 6% 2 5% 3 2 3 2 4 6% 62%	7634
	11th to 20th	Night	3 3 1 2 2 2 2 2 4 5% 73%	7520
	21st to end	Night	12% 6% 2 4 3 4 4 3 5% 7% 50%	7746
February	1st to 10th	Night	8% 5% 1 4 3 3 2 3 4 5% 61%	2520
	11th to 20th	Night	9% 6% 2 5% 3 3 4 3 5% 6% 56%	2458
	21st to end	Night	6% 5% 1 3 3 3 3 2 4 6% 64%	2076
March	1st to 10th	Night	5% 4 1 3 3 3 3 3 4 6% 66%	5494
	11th to 20th	Night	9% 4 1 4 2 2 3 2 4 6% 63%	5151
	21st to end	Night	3 4 1 4 3 3 4 3 5% 7% 62%	5588
April	1st to 10th	Night	7% 4 2 4 3 3 3 2 4 7% 60%	2101
	11th to 20th	Night	8% 4 1 4 2 3 3 3 4 6% 61%	2077
	21st to end	Night	8% 4 2 3 3 2 3 2 4 5% 64%	2100
May	1st to 10th	Night	11% 5% 1 4 3 3 4 3 5% 6% 56%	5316
	11th to 20th	Night	5% 3 1 4 3 3 3 3 5% 7% 64%	5265
	21st to end	Night	8% 4 1 5% 3 4 4 4 6% 8% 52%	5803
June	1st to 10th	Night	2 2 1 3 4 3 4 4 7% 9% 60%	1890
	11th to 20th	Night	2 2 1 3 3 3 4 4 6% 9% 63%	1890
	21st to end	Night	2 2 1 3 2 2 2 4 6% 10% 65%	1890
July	1st to 10th	Night	6% 4 2 5% 4 4 4 4 6% 12% 50%	5310
	11th to 20th	Night	3 3 1 5% 3 3 3 3 5% 9% 61%	5310
	21st to end	Night	2 1 2 2 2 3 3 5% 7% 73%	5878
August	1st to 10th	Night	1 1 1 3 2 2 3 3 4 6% 74%	4564
	11th to 20th	Night	2 2 1 3 3 4 4 4 6% 12% 61%	4523
	21st to end	Night	2 2 1 3 3 3 3 3 6% 10% 64%	4993
September	1st to 10th	Night	7% 4 1 5% 3 3 4 3 5% 9% 55%	2090
	11th to 20th	Night	8% 4 2 5% 3 3 4 4 7% 8% 54%	2200
	21st to end	Night	8% 3 1 4 3 3 3 3 5% 6% 60%	2200
October	1st to 10th	Night	2 2 1 3 2 2 2 2 3 4 78%	3590
	11th to 20th	Night	7% 3 2 3 2 2 2 2 3 4 71%	3570
	21st to end	Night	5% 2 1 2 1 1 2 2 2 3 79%	4301
November	1st to 10th	Night	7% 3 1 3 2 2 2 2 4 5% 69%	2665
	11th to 20th	Night	4 2 1 3 2 3 3 3 5% 7% 67%	2730
	21st to end	Night	10% 4 1 3 3 3 4 3 4 6% 58%	2730
December	1st to 10th	Night	10% 6% 2 4 3 2 3 3 4 5% 57%	4380
	11th to 20th	Night	5% 3 1 5% 3 3 3 3 4 5% 64%	4946
	21st to end	Night	6% 5% 1 4 3 3 3 3 4 5% 64%	6633

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	25% 3 5% 20% 31% 14%	5290
	11th to 20th	Day	15% 2 6% 24% 37% 17%	5527
	21st to end	Day	32% 3 5% 19% 26% 15%	6468
February	1st to 10th	Day	25% 3 6% 17% 28% 21%	2100
	11th to 20th	Day	29% 3 6% 23% 23% 17%	2059
	21st to end	Day	26% 2 3 13% 32% 23%	1730
March	1st to 10th	Day	23% 2 4 13% 24% 33%	4600
	11th to 20th	Day	27% 3 6% 10% 23% 31%	5017
	21st to end	Day	22% 4 6% 16% 26% 25%	5585
April	1st to 10th	Day	23% 4 7% 18% 23% 26%	2513
	11th to 20th	Day	28% 3 7% 14% 27% 21%	2494
	21st to end	Day	23% 3 7% 21% 27% 19%	2520
May	1st to 10th	Day	32% 4 7% 19% 21% 17%	7631
	11th to 20th	Day	28% 3 7% 12% 30% 20%	7631
	21st to end	Day	32% 6% 11% 24% 15% 13%	8405
June	1st to 10th	Day	18% 5% 15% 31% 23% 8%	2730
	11th to 20th	Day	19% 4 11% 26% 28% 13%	2730
	21st to end	Day	20% 5% 12% 26% 25% 12%	2730
July	1st to 10th	Day	26% 5% 12% 29% 24% 4	7616
	11th to 20th	Day	26% 6% 15% 31% 19% 3	7611
	21st to end	Day	11% 4 11% 34% 35% 5%	8042
August	1st to 10th	Day	12% 3 10% 30% 36% 9%	4012
	11th to 20th	Day	18% 4 12% 32% 29% 5%	3931
	21st to end	Day	22% 7% 15% 26% 25% 6%	4311
September	1st to 10th	Day	29% 5% 11% 20% 25% 10%	2308
	11th to 20th	Day	31% 6% 10% 23% 23% 7%	2200
	21st to end	Day	26% 3 7% 21% 28% 15%	2200
October	1st to 10th	Day	13% 2 7% 13% 31% 34%	3590
	11th to 20th	Day	24% 2 4 20% 23% 28%	3568
	21st to end	Day	15% 2 2 25% 41% 15%	3442
November	1st to 10th	Day	21% 3 5% 21% 29% 21%	1853
	11th to 20th	Day	20% 3 7% 21% 30% 19%	1890
	21st to end	Day	27% 2 6% 19% 30% 16%	1890
December	1st to 10th	Day	34% 2 4 19% 28% 13%	3030
	11th to 20th	Day	24% 3 7% 18% 30% 19%	3479
	21st to end	Day	21% 2 3 22% 33% 19%	4587
January	1st to 10th	Night	25% 2 4 22% 34% 13%	7635
	11th to 20th	Night	15% 2 6% 20% 35% 21%	7520
	21st to end	Night	34% 3 5% 18% 25% 15%	7746
February	1st to 10th	Night	26% 3 5% 15% 27% 23%	2520
	11th to 20th	Night	30% 3 6% 20% 22% 19%	2458
	21st to end	Night	24% 2 4 13% 28% 29%	2076
March	1st to 10th	Night	20% 2 4 13% 27% 34%	5494
	11th to 20th	Night	24% 3 7% 12% 16% 38%	5151
	21st to end	Night	21% 4 8% 17% 29% 22%	5588
April	1st to 10th	Night	25% 4 7% 20% 20% 24%	2101
	11th to 20th	Night	25% 3 8% 17% 25% 22%	2077
	21st to end	Night	23% 3 8% 21% 28% 16%	2100
May	1st to 10th	Night	28% 5% 9% 24% 17% 17%	5317
	11th to 20th	Night	20% 4 8% 16% 32% 20%	5266
	21st to end	Night	27% 6% 15% 20% 13% 18%	5805
June	1st to 10th	Night	18% 5% 16% 32% 22% 7%	1890
	11th to 20th	Night	16% 5% 12% 27% 28% 11%	1890
	21st to end	Night	15% 3 14% 30% 25% 12%	1890
July	1st to 10th	Night	27% 4 12% 32% 21% 3	5265
	11th to 20th	Night	21% 5% 15% 32% 23% 4	5256
	21st to end	Night	11% 3 11% 33% 35% 6%	5748
August	1st to 10th	Night	12% 3 7% 27% 40% 10%	3344
	11th to 20th	Night	14% 4 12% 33% 30% 6%	3283
	21st to end	Night	17% 5% 19% 26% 26% 7%	3597
September	1st to 10th	Night	27% 4 10% 24% 21% 13%	2090
	11th to 20th	Night	26% 5% 13% 23% 25% 9%	2200
	21st to end	Night	24% 4 6% 22% 25% 19%	2200
October	1st to 10th	Night	12% 2 6% 15% 29% 36%	3590
	11th to 20th	Night	20% 2 6% 18% 24% 30%	3570
	21st to end	Night	13% 2 3 24% 39% 19%	4301
November	1st to 10th	Night	19% 3 6% 22% 27% 22%	2665
	11th to 20th	Night	18% 3 7% 18% 32% 21%	2730
	21st to end	Night	27% 4 5% 15% 31% 17%	2730
December	1st to 10th	Night	30% 2 5% 19% 28% 15%	4380
	11th to 20th	Night	24% 3 6% 18% 32% 19%	4947
	21st to end	Night	24% 3 4 23% 28% 18%	6633

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	10% 8% 35% 32% 13% 2	330
	11th to 20th	Day	9% 10% 32% 31% 15% 3	330
	21st to end	Day	11% 8% 31% 33% 14% 2	363
February	1st to 10th	Day	14% 6% 32% 28% 18% 3	330
	11th to 20th	Day	12% 9% 39% 27% 13% 1	330
	21st to end	Day	12% 7% 39% 26% 13% 1	273
March	1st to 10th	Day	12% 7% 38% 31% 12% 1	330
	11th to 20th	Day	16% 9% 32% 27% 15% 1	330
	21st to end	Day	6% 9% 40% 31% 10% 2	363
April	1st to 10th	Day	9% 11% 42% 27% 10% 1	533
	11th to 20th	Day	12% 12% 46% 23% 6% 1	532
	21st to end	Day	7% 12% 41% 27% 10% 2	540
May	1st to 10th	Day	12% 7% 35% 32% 13% 2	742
	11th to 20th	Day	13% 5% 28% 35% 15% 4	775
	21st to end	Day	9% 3 30% 41% 16% 1	844
June	1st to 10th	Day	5% 3 16% 47% 25% 5%	780
	11th to 20th	Day	4 2 18% 45% 26% 5%	780
	21st to end	Day	4 1 11% 39% 36% 10%	780
July	1st to 10th	Day	8% 1 5% 30% 42% 14%	771
	11th to 20th	Day	3 2 4 33% 45% 14%	768
	21st to end	Day	1 2 27% 47% 22%	811
August	1st to 10th	Day	3 1 2 24% 48% 23%	567
	11th to 20th	Day	4 1 3 31% 39% 21%	534
	21st to end	Day	4 1 3 26% 43% 23%	583
September	1st to 10th	Day	9% 1 3 24% 39% 23%	438
	11th to 20th	Day	6% 1 4 25% 41% 24%	330
	21st to end	Day	13% 6% 24% 35% 22%	330
October	1st to 10th	Day	4 1 10% 31% 38% 15%	330
	11th to 20th	Day	11% 2 23% 28% 32% 4	330
	21st to end	Day	14% 6% 21% 29% 23% 8%	363
November	1st to 10th	Day	12% 5% 22% 30% 25% 7%	330
	11th to 20th	Day	10% 7% 24% 26% 25% 8%	330
	21st to end	Day	14% 9% 32% 25% 14% 7%	330
December	1st to 10th	Day	14% 5% 26% 35% 17% 4	330
	11th to 20th	Day	7% 9% 27% 38% 17% 3	330
	21st to end	Day	12% 7% 30% 33% 16% 2	363
January	1st to 10th	Night	10% 7% 33% 40% 10% 1	1050
	11th to 20th	Night	10% 8% 31% 40% 10%	994
	21st to end	Night	10% 7% 35% 40% 8%	924
February	1st to 10th	Night	11% 5% 37% 37% 10%	840
	11th to 20th	Night	11% 9% 40% 35% 6%	824
	21st to end	Night	10% 9% 44% 34% 3	692
March	1st to 10th	Night	12% 8% 40% 35% 4	840
	11th to 20th	Night	13% 8% 39% 35% 5%	665
	21st to end	Night	8% 9% 48% 31% 4	693
April	1st to 10th	Night	8% 9% 49% 30% 4	630
	11th to 20th	Night	9% 9% 51% 29% 1	623
	21st to end	Night	10% 8% 48% 30% 4	630
May	1st to 10th	Night	8% 5% 47% 36% 4	630
	11th to 20th	Night	8% 5% 38% 39% 10% 1	621
	21st to end	Night	8% 2 38% 44% 8%	683
June	1st to 10th	Night	3 1 28% 53% 15%	630
	11th to 20th	Night	3 2 32% 53% 10%	630
	21st to end	Night	4 1 18% 53% 24%	630
July	1st to 10th	Night	7% 2 7% 50% 32% 2	615
	11th to 20th	Night	3 5% 53% 36% 2	612
	21st to end	Night	1 4 52% 40% 2	690
August	1st to 10th	Night	1 5% 49% 43% 2	627
	11th to 20th	Night	4 1 5% 49% 39% 2	606
	21st to end	Night	2 1 5% 40% 47% 4	660
September	1st to 10th	Night	9% 1 5% 45% 38% 3	600
	11th to 20th	Night	10% 8% 46% 34% 2	600
	21st to end	Night	10% 1 12% 47% 30% 1	600
October	1st to 10th	Night	4 1 21% 51% 22% 1	600
	11th to 20th	Night	8% 4 25% 47% 16% 1	600
	21st to end	Night	9% 5% 26% 37% 21% 1	904
November	1st to 10th	Night	9% 3 25% 44% 18% 1	1025
	11th to 20th	Night	6% 5% 28% 44% 15% 1	1050
	21st to end	Night	13% 4 31% 38% 14%	1050
December	1st to 10th	Night	11% 4 31% 41% 12%	1050
	11th to 20th	Night	10% 6% 34% 40% 9%	1050
	21st to end	Night	9% 6% 32% 42% 10%	1155

Page generated at 2026-08-12 02:37:16. Version ac07

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