Carlyle Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carlyle Lake clear sky chart from 2005-11-06 to 2026-06-16.

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% 7% 3 7% 4 4 4 4 6% 8% 41%	137519
	Night	14% 8% 3 7% 4 4 4 3 5% 7% 42%	134763
Transparency	Day	39% 7% 12% 24% 16% 2	141095
	Night	40% 6% 11% 23% 17% 2	139254
Seeing	Day	15% 10% 25% 26% 18% 7%	17765
	Night	16% 9% 28% 31% 14% 2	27612

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% 9% 5% 12% 5% 4 4 3 5% 7% 33%	4691
	11th to 20th	Day	8% 9% 3 7% 5% 6% 5% 4 5% 6% 41%	4830
	21st to end	Day	18% 12% 4 8% 5% 4 4 3 4 5% 33%	5812
February	1st to 10th	Day	17% 10% 5% 6% 4 3 5% 3 5% 6% 36%	1959
	11th to 20th	Day	15% 10% 3 8% 5% 4 4 4 5% 6% 36%	2048
	21st to end	Day	14% 9% 3 8% 5% 4 4 4 5% 6% 38%	1730
March	1st to 10th	Day	17% 11% 3 5% 3 3 3 2 3 5% 46%	4580
	11th to 20th	Day	10% 8% 2 5% 4 3 4 3 6% 7% 49%	4940
	21st to end	Day	14% 8% 2 8% 5% 5% 5% 4 6% 8% 36%	6038
April	1st to 10th	Day	14% 7% 2 6% 4 4 3 4 6% 8% 41%	2520
	11th to 20th	Day	16% 8% 3 5% 4 4 4 3 5% 6% 41%	2494
	21st to end	Day	15% 6% 3 7% 5% 5% 4 3 5% 7% 40%	2520
May	1st to 10th	Day	16% 7% 2 8% 5% 5% 5% 4 7% 9% 31%	7454
	11th to 20th	Day	14% 8% 3 7% 4 4 5% 3 5% 7% 40%	7821
	21st to end	Day	15% 8% 3 7% 5% 5% 6% 4 6% 8% 33%	9047
June	1st to 10th	Day	8% 5% 2 5% 4 5% 5% 4 6% 8% 47%	2940
	11th to 20th	Day	7% 4 2 6% 5% 4 4 4 6% 8% 49%	2871
	21st to end	Day	5% 4 2 6% 4 5% 5% 5% 8% 10% 46%	2800
July	1st to 10th	Day	9% 5% 2 5% 4 4 4 4 6% 9% 47%	6360
	11th to 20th	Day	6% 5% 2 6% 6% 6% 6% 5% 8% 11% 39%	6360
	21st to end	Day	7% 6% 2 7% 5% 6% 5% 5% 8% 10% 39%	6840
August	1st to 10th	Day	6% 4 2 4 4 4 4 4 6% 10% 54%	4079
	11th to 20th	Day	10% 5% 2 5% 4 4 5% 4 7% 10% 43%	3849
	21st to end	Day	5% 4 2 4 4 4 4 4 6% 9% 54%	4312
September	1st to 10th	Day	11% 6% 2 5% 4 3 4 3 4 8% 50%	2400
	11th to 20th	Day	7% 5% 2 6% 4 4 4 3 5% 8% 51%	2315
	21st to end	Day	9% 4 2 6% 4 5% 4 4 6% 6% 51%	2200
October	1st to 10th	Day	9% 5% 1 4 3 3 4 2 4 7% 57%	2096
	11th to 20th	Day	13% 5% 2 5% 3 3 4 3 5% 7% 51%	2000
	21st to end	Day	18% 7% 2 5% 3 2 4 2 4 5% 47%	2100
November	1st to 10th	Day	10% 6% 2 5% 3 3 3 3 5% 6% 55%	1852
	11th to 20th	Day	14% 8% 3 6% 4 3 3 3 4 5% 46%	1890
	21st to end	Day	17% 10% 4 8% 5% 3 3 4 4 5% 39%	1890
December	1st to 10th	Day	9% 10% 3 6% 4 4 4 3 5% 6% 48%	2723
	11th to 20th	Day	14% 9% 5% 8% 4 5% 5% 3 4 6% 36%	3088
	21st to end	Day	27% 15% 4 10% 5% 4 4 3 4 4 22%	4070
January	1st to 10th	Night	14% 11% 5% 10% 4 4 4 3 5% 5% 36%	8232
	11th to 20th	Night	11% 11% 4 10% 4 5% 6% 3 4 5% 38%	8142
	21st to end	Night	18% 11% 5% 8% 4 4 4 3 4 6% 34%	8402
February	1st to 10th	Night	16% 10% 5% 8% 5% 4 3 5% 5% 5% 34%	2659
	11th to 20th	Night	16% 8% 3 7% 4 4 3 3 6% 6% 38%	2458
	21st to end	Night	16% 9% 3 8% 5% 3 4 3 5% 5% 40%	2076
March	1st to 10th	Night	17% 12% 3 6% 3 4 4 3 4 5% 39%	5493
	11th to 20th	Night	12% 7% 2 5% 4 3 3 3 4 6% 51%	5283
	21st to end	Night	17% 8% 3 7% 5% 5% 4 4 5% 6% 36%	5131
April	1st to 10th	Night	13% 7% 2 6% 4 4 4 3 5% 5% 46%	2100
	11th to 20th	Night	15% 6% 2 5% 4 4 3 4 5% 8% 43%	2075
	21st to end	Night	18% 6% 3 7% 4 4 4 4 4 6% 40%	2100
May	1st to 10th	Night	16% 7% 3 8% 4 5% 5% 4 6% 8% 34%	5398
	11th to 20th	Night	12% 6% 2 6% 4 5% 5% 4 6% 9% 41%	5033
	21st to end	Night	15% 7% 3 8% 6% 5% 5% 4 6% 9% 32%	5139
June	1st to 10th	Night	9% 5% 2 6% 4 4 4 3 5% 9% 49%	1680
	11th to 20th	Night	6% 4 2 5% 5% 4 4 3 6% 8% 52%	1640
	21st to end	Night	5% 4 2 4 4 4 5% 5% 7% 10% 50%	1600
July	1st to 10th	Night	11% 5% 2 5% 4 3 4 4 5% 9% 49%	3618
	11th to 20th	Night	6% 5% 2 6% 4 5% 5% 5% 7% 9% 46%	3617
	21st to end	Night	6% 5% 2 6% 6% 5% 6% 5% 7% 12% 40%	4027
August	1st to 10th	Night	6% 3 1 5% 3 4 4 4 7% 9% 56%	3075
	11th to 20th	Night	9% 4 2 6% 3 4 5% 4 6% 8% 49%	3200
	21st to end	Night	6% 3 1 4 3 3 4 4 6% 9% 59%	3586
September	1st to 10th	Night	10% 5% 2 5% 4 3 4 3 5% 6% 53%	2000
	11th to 20th	Night	7% 5% 2 5% 3 3 4 3 5% 7% 55%	2065
	21st to end	Night	11% 5% 2 5% 4 4 4 4 4 6% 52%	2200
October	1st to 10th	Night	7% 5% 2 4 3 3 3 3 4 6% 60%	2300
	11th to 20th	Night	14% 4 2 5% 3 3 3 2 3 5% 56%	2400
	21st to end	Night	19% 7% 2 5% 3 3 3 3 4 5% 45%	2738
November	1st to 10th	Night	10% 6% 2 5% 3 3 3 3 5% 5% 54%	2666
	11th to 20th	Night	13% 6% 2 5% 3 4 3 3 5% 7% 48%	2730
	21st to end	Night	20% 8% 3 7% 3 3 3 2 4 5% 42%	2730
December	1st to 10th	Night	14% 9% 3 7% 4 3 3 3 5% 5% 44%	4681
	11th to 20th	Night	17% 7% 3 6% 3 3 4 3 5% 7% 42%	5339
	21st to end	Night	29% 15% 4 8% 5% 4 4 2 3 4 23%	7150

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	50% 6% 12% 24% 8% 1	4692
	11th to 20th	Day	41% 5% 11% 24% 16% 3	4830
	21st to end	Day	54% 4 9% 17% 12% 4	5812
February	1st to 10th	Day	49% 5% 12% 24% 9% 1	1959
	11th to 20th	Day	49% 5% 10% 21% 13% 3	2058
	21st to end	Day	47% 5% 10% 21% 14% 3	1730
March	1st to 10th	Day	43% 4 5% 22% 22% 4	4580
	11th to 20th	Day	33% 5% 10% 29% 19% 4	4940
	21st to end	Day	43% 8% 14% 24% 10% 1	6040
April	1st to 10th	Day	39% 8% 13% 24% 16% 1	2520
	11th to 20th	Day	43% 6% 11% 24% 14% 3	2494
	21st to end	Day	44% 7% 11% 26% 11% 2	2520
May	1st to 10th	Day	45% 9% 14% 21% 10%	7491
	11th to 20th	Day	43% 7% 10% 23% 16% 1	7825
	21st to end	Day	47% 8% 10% 19% 15% 1	9061
June	1st to 10th	Day	32% 9% 14% 26% 16% 3	2940
	11th to 20th	Day	31% 8% 13% 24% 22% 3	2871
	21st to end	Day	29% 10% 17% 23% 16% 4	2800
July	1st to 10th	Day	32% 7% 11% 30% 17% 3	6291
	11th to 20th	Day	34% 11% 16% 26% 12% 1	6285
	21st to end	Day	35% 10% 18% 26% 10% 1	6645
August	1st to 10th	Day	26% 7% 13% 39% 15% 1	4065
	11th to 20th	Day	33% 8% 15% 26% 17% 1	3885
	21st to end	Day	26% 7% 14% 35% 15% 3	4311
September	1st to 10th	Day	34% 6% 11% 25% 21% 3	2400
	11th to 20th	Day	31% 6% 10% 25% 25% 3	2315
	21st to end	Day	32% 6% 10% 23% 26% 4	2200
October	1st to 10th	Day	18% 3 7% 23% 43% 7%	3408
	11th to 20th	Day	24% 4 8% 21% 36% 7%	3240
	21st to end	Day	32% 3 7% 26% 28% 3	3377
November	1st to 10th	Day	31% 4 12% 28% 19% 5%	1852
	11th to 20th	Day	40% 4 10% 23% 18% 5%	1890
	21st to end	Day	48% 5% 8% 25% 14% 1	1890
December	1st to 10th	Day	37% 5% 14% 28% 16%	2723
	11th to 20th	Day	47% 5% 10% 24% 12% 1	3085
	21st to end	Day	66% 4 11% 12% 5% 1	4070
January	1st to 10th	Night	50% 5% 13% 24% 7%	8233
	11th to 20th	Night	48% 5% 7% 21% 17% 3	8142
	21st to end	Night	52% 4 11% 18% 15% 1	8402
February	1st to 10th	Night	51% 5% 10% 22% 11% 1	2659
	11th to 20th	Night	45% 4 11% 21% 16% 2	2459
	21st to end	Night	46% 5% 10% 23% 13% 3	2076
March	1st to 10th	Night	47% 5% 6% 21% 19% 2	5493
	11th to 20th	Night	35% 5% 10% 24% 22% 4	5283
	21st to end	Night	46% 7% 10% 26% 9% 1	5131
April	1st to 10th	Night	39% 6% 11% 26% 16% 3	2100
	11th to 20th	Night	39% 5% 12% 22% 18% 3	2075
	21st to end	Night	45% 7% 9% 23% 14% 3	2100
May	1st to 10th	Night	45% 9% 14% 21% 9% 1	5426
	11th to 20th	Night	38% 8% 13% 24% 16% 1	5034
	21st to end	Night	46% 9% 11% 20% 12% 2	5149
June	1st to 10th	Night	32% 8% 13% 24% 20% 3	1680
	11th to 20th	Night	28% 7% 12% 25% 23% 5%	1640
	21st to end	Night	27% 8% 15% 25% 18% 7%	1600
July	1st to 10th	Night	32% 6% 10% 27% 23% 3	3580
	11th to 20th	Night	31% 9% 15% 29% 14% 2	3572
	21st to end	Night	34% 9% 20% 25% 11% 1	3911
August	1st to 10th	Night	23% 8% 17% 34% 17% 1	3065
	11th to 20th	Night	32% 8% 13% 25% 21% 1	3230
	21st to end	Night	22% 6% 14% 34% 21% 3	3586
September	1st to 10th	Night	31% 5% 9% 27% 21% 6%	2000
	11th to 20th	Night	29% 5% 9% 29% 23% 4	2065
	21st to end	Night	31% 7% 9% 20% 27% 6%	2200
October	1st to 10th	Night	16% 3 6% 19% 47% 8%	3755
	11th to 20th	Night	23% 3 8% 23% 37% 6%	3899
	21st to end	Night	33% 4 8% 24% 25% 7%	4411
November	1st to 10th	Night	32% 4 11% 24% 23% 5%	2666
	11th to 20th	Night	36% 4 10% 24% 22% 4	2730
	21st to end	Night	45% 3 9% 24% 17% 1	2730
December	1st to 10th	Night	43% 4 11% 27% 15% 1	4681
	11th to 20th	Night	43% 4 13% 24% 16%	5341
	21st to end	Night	65% 6% 10% 14% 5% 1	7150

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	23% 16% 31% 22% 7%	330
	11th to 20th	Day	24% 20% 34% 20% 2	330
	21st to end	Day	23% 18% 37% 17% 4	363
February	1st to 10th	Day	27% 12% 40% 17% 3	330
	11th to 20th	Day	25% 22% 32% 16% 4 1	330
	21st to end	Day	24% 19% 36% 19% 2	273
March	1st to 10th	Day	21% 18% 42% 16% 4	330
	11th to 20th	Day	27% 17% 37% 14% 5% 1	330
	21st to end	Day	26% 15% 35% 20% 4	559
April	1st to 10th	Day	19% 16% 32% 24% 8% 1	540
	11th to 20th	Day	20% 18% 27% 21% 11% 2	532
	21st to end	Day	16% 14% 36% 22% 11% 1	540
May	1st to 10th	Day	18% 14% 29% 29% 8% 2	543
	11th to 20th	Day	16% 10% 26% 27% 16% 5%	632
	21st to end	Day	10% 7% 29% 30% 17% 8%	844
June	1st to 10th	Day	9% 4 19% 31% 26% 11%	780
	11th to 20th	Day	9% 3 19% 35% 26% 8%	756
	21st to end	Day	6% 5% 22% 34% 25% 7%	730
July	1st to 10th	Day	10% 3 12% 26% 29% 20%	721
	11th to 20th	Day	6% 4 13% 35% 30% 13%	718
	21st to end	Day	8% 1 11% 32% 35% 13%	794
August	1st to 10th	Day	8% 2 12% 32% 31% 14%	636
	11th to 20th	Day	9% 3 14% 29% 31% 15%	519
	21st to end	Day	8% 2 11% 27% 36% 16%	583
September	1st to 10th	Day	10% 3 17% 26% 29% 15%	530
	11th to 20th	Day	7% 3 10% 27% 39% 16%	530
	21st to end	Day	12% 6% 21% 25% 24% 13%	530
October	1st to 10th	Day	9% 6% 21% 34% 24% 7%	426
	11th to 20th	Day	14% 14% 30% 23% 14% 5%	330
	21st to end	Day	28% 16% 28% 20% 8%	363
November	1st to 10th	Day	12% 10% 36% 23% 13% 5%	330
	11th to 20th	Day	18% 17% 33% 20% 9% 3	330
	21st to end	Day	25% 14% 28% 23% 8% 2	330
December	1st to 10th	Day	14% 20% 39% 18% 5% 5%	330
	11th to 20th	Day	22% 16% 35% 21% 6% 1	330
	21st to end	Day	27% 18% 35% 17% 3	363
January	1st to 10th	Night	20% 14% 37% 25% 4	1050
	11th to 20th	Night	21% 17% 35% 23% 4	1050
	21st to end	Night	20% 14% 39% 25% 2	1155
February	1st to 10th	Night	20% 12% 40% 26% 2	979
	11th to 20th	Night	21% 16% 37% 23% 2	823
	21st to end	Night	22% 15% 39% 23% 2	692
March	1st to 10th	Night	20% 16% 36% 24% 4	840
	11th to 20th	Night	22% 13% 33% 26% 5%	719
	21st to end	Night	23% 10% 34% 28% 6%	693
April	1st to 10th	Night	16% 13% 37% 27% 6%	630
	11th to 20th	Night	18% 9% 35% 28% 10%	623
	21st to end	Night	20% 7% 36% 27% 8% 1	630
May	1st to 10th	Night	17% 8% 30% 36% 10%	630
	11th to 20th	Night	11% 6% 28% 36% 18% 2	621
	21st to end	Night	10% 4 22% 40% 21% 3	683
June	1st to 10th	Night	10% 3 19% 41% 25% 1	630
	11th to 20th	Night	8% 2 18% 46% 25% 2	615
	21st to end	Night	6% 2 20% 43% 28% 2	600
July	1st to 10th	Night	11% 2 8% 33% 38% 8%	585
	11th to 20th	Night	5% 2 13% 41% 36% 3	582
	21st to end	Night	5% 1 12% 40% 37% 4	657
August	1st to 10th	Night	8% 2 9% 42% 35% 4	597
	11th to 20th	Night	7% 1 13% 39% 35% 5%	594
	21st to end	Night	8% 1 8% 37% 42% 4	660
September	1st to 10th	Night	11% 2 14% 37% 31% 5%	600
	11th to 20th	Night	8% 2 13% 37% 34% 6%	665
	21st to end	Night	12% 5% 20% 32% 25% 6%	800
October	1st to 10th	Night	8% 4 22% 38% 24% 4	800
	11th to 20th	Night	15% 9% 28% 31% 16% 1	800
	21st to end	Night	23% 10% 31% 29% 7%	880
November	1st to 10th	Night	13% 7% 36% 34% 10%	820
	11th to 20th	Night	16% 10% 35% 29% 9%	840
	21st to end	Night	24% 12% 32% 25% 7%	840
December	1st to 10th	Night	21% 13% 34% 26% 5%	1024
	11th to 20th	Night	23% 8% 34% 30% 5%	1050
	21st to end	Night	28% 13% 35% 21% 3	1155

Page generated at 2026-06-13 01:31:42. Version ac07

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