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 2025-02-21.

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 6% 4 4 4 4 5% 7% 42%	108578
	Night	15% 8% 3 7% 4 4 4 3 5% 6% 42%	110178
Transparency	Day	39% 7% 12% 25% 16% 2	112196
	Night	40% 6% 11% 23% 17% 3	114688
Seeing	Day	15% 9% 24% 26% 18% 7%	15932
	Night	16% 9% 28% 31% 14% 2	25906

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	14% 10% 6% 13% 5% 4 4 3 5% 6% 30%	3617
	11th to 20th	Day	10% 9% 4 7% 6% 7% 5% 5% 4 5% 37%	3712
	21st to end	Day	20% 12% 4 7% 4 3 3 3 4 5% 34%	4488
February	1st to 10th	Day	18% 11% 5% 6% 4 3 5% 3 5% 6% 36%	1865
	11th to 20th	Day	16% 10% 3 8% 6% 3 4 4 5% 6% 36%	1948
	21st to end	Day	15% 9% 4 8% 4 4 4 4 5% 6% 37%	1570
March	1st to 10th	Day	20% 13% 3 6% 3 3 3 2 3 6% 37%	3120
	11th to 20th	Day	12% 7% 3 5% 4 3 4 4 5% 7% 47%	3375
	21st to end	Day	14% 9% 2 8% 5% 5% 5% 4 6% 7% 35%	4120
April	1st to 10th	Day	13% 6% 2 6% 5% 4 3 4 6% 9% 42%	2280
	11th to 20th	Day	16% 8% 3 6% 4 4 5% 3 4 6% 42%	2254
	21st to end	Day	16% 7% 3 6% 5% 5% 5% 3 5% 6% 40%	2280
May	1st to 10th	Day	14% 7% 2 6% 6% 6% 5% 4 7% 10% 33%	4004
	11th to 20th	Day	17% 8% 3 6% 4 4 4 3 5% 7% 40%	4192
	21st to end	Day	9% 5% 2 6% 5% 5% 5% 4 6% 8% 45%	4824
June	1st to 10th	Day	8% 5% 2 5% 4 5% 5% 5% 7% 8% 47%	2660
	11th to 20th	Day	7% 4 2 6% 5% 4 4 4 6% 8% 50%	2660
	21st to end	Day	5% 4 2 6% 4 5% 5% 5% 8% 10% 46%	2660
July	1st to 10th	Day	12% 5% 2 6% 4 5% 5% 4 7% 9% 42%	4440
	11th to 20th	Day	5% 4 1 5% 5% 5% 5% 4 7% 11% 48%	4440
	21st to end	Day	7% 6% 2 7% 5% 6% 5% 5% 8% 10% 39%	4757
August	1st to 10th	Day	6% 4 2 4 4 4 4 4 6% 10% 53%	3954
	11th to 20th	Day	10% 5% 2 5% 4 4 5% 4 7% 10% 43%	3729
	21st to end	Day	5% 4 2 5% 4 4 4 4 6% 9% 54%	4180
September	1st to 10th	Day	12% 6% 2 5% 4 3 4 3 4 7% 49%	2280
	11th to 20th	Day	7% 5% 2 6% 4 5% 5% 4 5% 8% 50%	2199
	21st to end	Day	10% 4 2 6% 4 5% 4 4 6% 6% 51%	2090
October	1st to 10th	Day	9% 5% 1 4 3 3 4 2 4 6% 57%	1991
	11th to 20th	Day	13% 5% 2 5% 3 3 4 3 5% 6% 51%	1900
	21st to end	Day	17% 7% 2 6% 3 3 4 2 4 6% 47%	1995
November	1st to 10th	Day	10% 6% 1 5% 3 3 3 3 5% 6% 54%	1762
	11th to 20th	Day	14% 8% 3 6% 4 3 4 3 4 5% 45%	1800
	21st to end	Day	16% 10% 4 7% 6% 3 3 4 4 5% 39%	1800
December	1st to 10th	Day	9% 10% 3 6% 4 4 4 3 5% 6% 48%	2642
	11th to 20th	Day	14% 9% 5% 8% 4 5% 5% 3 4 6% 36%	3008
	21st to end	Day	27% 15% 4 10% 5% 4 4 3 4 4 22%	3982
January	1st to 10th	Night	16% 11% 5% 11% 4 4 4 3 4 5% 32%	6348
	11th to 20th	Night	13% 12% 5% 11% 4 5% 6% 3 3 4 34%	6250
	21st to end	Night	20% 11% 5% 8% 4 3 3 3 4 5% 34%	6490
February	1st to 10th	Night	17% 10% 5% 8% 5% 4 3 5% 4 5% 33%	2533
	11th to 20th	Night	16% 8% 3 8% 5% 4 3 3 5% 6% 38%	2338
	21st to end	Night	17% 9% 3 9% 5% 4 4 3 5% 5% 38%	1885
March	1st to 10th	Night	20% 12% 2 6% 4 4 4 3 3 5% 38%	3733
	11th to 20th	Night	14% 6% 2 5% 3 3 3 3 4 6% 51%	3613
	21st to end	Night	18% 8% 3 7% 5% 4 4 3 5% 7% 36%	3509
April	1st to 10th	Night	13% 6% 2 6% 4 4 4 3 5% 5% 47%	1900
	11th to 20th	Night	16% 6% 2 5% 4 4 4 4 5% 8% 43%	1875
	21st to end	Night	19% 7% 3 7% 4 4 4 4 4 6% 40%	1900
May	1st to 10th	Night	16% 8% 2 6% 4 4 4 4 5% 8% 37%	2890
	11th to 20th	Night	15% 7% 2 6% 4 4 4 4 5% 6% 43%	2702
	21st to end	Night	10% 6% 2 6% 5% 4 5% 4 7% 9% 41%	2743
June	1st to 10th	Night	9% 5% 2 5% 4 4 4 3 5% 9% 50%	1520
	11th to 20th	Night	5% 4 2 5% 4 4 4 3 6% 8% 53%	1520
	21st to end	Night	6% 4 2 4 4 5% 5% 5% 7% 10% 49%	1520
July	1st to 10th	Night	13% 4 1 5% 3 3 4 4 5% 9% 48%	2530
	11th to 20th	Night	5% 4 2 5% 3 4 4 4 6% 7% 56%	2530
	21st to end	Night	7% 5% 3 7% 6% 5% 7% 5% 7% 10% 39%	2802
August	1st to 10th	Night	6% 3 1 5% 3 4 4 4 7% 9% 56%	2980
	11th to 20th	Night	9% 4 2 6% 3 4 5% 4 6% 8% 49%	3100
	21st to end	Night	6% 3 1 4 3 3 4 4 6% 9% 58%	3476
September	1st to 10th	Night	10% 5% 1 5% 4 3 3 3 4 6% 54%	1900
	11th to 20th	Night	7% 6% 2 6% 3 3 4 3 5% 7% 54%	1962
	21st to end	Night	11% 5% 2 5% 4 4 4 4 4 7% 52%	2090
October	1st to 10th	Night	8% 5% 2 4 3 3 3 3 4 6% 59%	2185
	11th to 20th	Night	14% 4 2 5% 3 3 3 3 3 5% 56%	2280
	21st to end	Night	19% 6% 2 5% 3 3 3 3 4 5% 45%	2601
November	1st to 10th	Night	11% 6% 2 5% 3 3 3 3 4 5% 54%	2536
	11th to 20th	Night	14% 7% 2 5% 3 4 3 3 5% 7% 47%	2600
	21st to end	Night	19% 8% 3 7% 3 3 3 2 4 5% 42%	2600
December	1st to 10th	Night	14% 9% 3 7% 4 3 3 3 5% 5% 45%	4542
	11th to 20th	Night	17% 7% 3 6% 3 3 4 3 5% 7% 42%	5199
	21st to end	Night	29% 15% 5% 8% 5% 4 4 2 3 4 22%	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	54% 6% 11% 20% 8% 1	3618
	11th to 20th	Day	45% 5% 11% 21% 14% 2	3712
	21st to end	Day	54% 4 7% 17% 14% 4	4488
February	1st to 10th	Day	49% 4 12% 23% 10% 1	1865
	11th to 20th	Day	49% 5% 10% 21% 13% 3	1958
	21st to end	Day	47% 5% 10% 20% 14% 3	1570
March	1st to 10th	Day	50% 5% 7% 21% 13% 4	3120
	11th to 20th	Day	36% 6% 13% 26% 15% 4	3375
	21st to end	Day	44% 10% 16% 22% 8% 1	4120
April	1st to 10th	Day	37% 8% 13% 25% 16% 1	2280
	11th to 20th	Day	43% 6% 10% 24% 14% 3	2254
	21st to end	Day	45% 7% 11% 24% 11% 2	2280
May	1st to 10th	Day	42% 12% 15% 23% 7%	4041
	11th to 20th	Day	44% 8% 11% 27% 10% 1	4196
	21st to end	Day	34% 10% 12% 22% 21% 1	4837
June	1st to 10th	Day	31% 9% 14% 27% 16% 3	2660
	11th to 20th	Day	30% 8% 13% 24% 22% 3	2660
	21st to end	Day	30% 10% 16% 23% 16% 5%	2660
July	1st to 10th	Day	36% 8% 11% 29% 13% 3	4371
	11th to 20th	Day	27% 9% 14% 32% 16% 2	4365
	21st to end	Day	36% 10% 17% 24% 12% 1	4607
August	1st to 10th	Day	26% 7% 13% 38% 15% 1	3940
	11th to 20th	Day	34% 8% 14% 26% 17% 1	3765
	21st to end	Day	26% 7% 14% 35% 15% 3	4179
September	1st to 10th	Day	35% 6% 11% 24% 20% 4	2280
	11th to 20th	Day	32% 6% 10% 25% 24% 3	2199
	21st to end	Day	32% 6% 10% 24% 24% 4	2090
October	1st to 10th	Day	18% 3 7% 23% 43% 7%	3303
	11th to 20th	Day	24% 4 8% 21% 36% 7%	3140
	21st to end	Day	32% 4 7% 26% 28% 3	3272
November	1st to 10th	Day	31% 4 12% 28% 19% 6%	1762
	11th to 20th	Day	40% 5% 10% 22% 18% 6%	1800
	21st to end	Day	47% 5% 8% 25% 14% 1	1800
December	1st to 10th	Day	37% 5% 14% 28% 16%	2642
	11th to 20th	Day	48% 6% 10% 24% 11% 1	3005
	21st to end	Day	66% 4 11% 12% 5% 1	3982
January	1st to 10th	Night	54% 5% 11% 23% 7% 1	6348
	11th to 20th	Night	53% 5% 8% 19% 12% 3	6250
	21st to end	Night	53% 4 8% 18% 16% 1	6490
February	1st to 10th	Night	52% 5% 10% 20% 11% 1	2533
	11th to 20th	Night	46% 4 11% 20% 17% 2	2339
	21st to end	Night	48% 5% 10% 20% 13% 3	1885
March	1st to 10th	Night	48% 6% 8% 22% 15% 2	3733
	11th to 20th	Night	34% 6% 12% 23% 22% 3	3613
	21st to end	Night	45% 9% 11% 27% 7% 1	3509
April	1st to 10th	Night	38% 6% 10% 26% 17% 3	1900
	11th to 20th	Night	39% 5% 10% 23% 19% 3	1875
	21st to end	Night	45% 7% 10% 22% 14% 3	1900
May	1st to 10th	Night	42% 11% 16% 20% 10% 1	2918
	11th to 20th	Night	39% 9% 12% 26% 14% 1	2703
	21st to end	Night	35% 11% 12% 23% 17% 2	2751
June	1st to 10th	Night	31% 8% 14% 23% 21% 3	1520
	11th to 20th	Night	26% 7% 12% 25% 24% 5%	1520
	21st to end	Night	27% 9% 15% 24% 18% 7%	1520
July	1st to 10th	Night	33% 6% 11% 28% 19% 4	2490
	11th to 20th	Night	24% 7% 12% 35% 19% 3	2482
	21st to end	Night	37% 9% 18% 22% 12% 2	2713
August	1st to 10th	Night	23% 8% 17% 34% 18% 1	2970
	11th to 20th	Night	32% 8% 12% 25% 22% 1	3130
	21st to end	Night	22% 7% 14% 34% 20% 3	3476
September	1st to 10th	Night	31% 5% 9% 28% 21% 7%	1900
	11th to 20th	Night	30% 5% 9% 29% 22% 5%	1962
	21st to end	Night	31% 7% 8% 21% 27% 6%	2090
October	1st to 10th	Night	16% 3 6% 19% 47% 8%	3640
	11th to 20th	Night	23% 3 7% 23% 37% 6%	3779
	21st to end	Night	32% 4 8% 24% 25% 7%	4274
November	1st to 10th	Night	32% 4 11% 24% 23% 5%	2536
	11th to 20th	Night	36% 4 10% 24% 22% 4	2600
	21st to end	Night	45% 3 9% 24% 18% 1	2600
December	1st to 10th	Night	42% 4 11% 27% 16% 1	4542
	11th to 20th	Night	42% 4 14% 24% 16%	5201
	21st to end	Night	65% 6% 10% 13% 5% 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	24% 17% 30% 22% 6%	300
	11th to 20th	Day	26% 19% 32% 21% 2	300
	21st to end	Day	23% 18% 37% 17% 4	330
February	1st to 10th	Day	30% 12% 39% 16% 3	300
	11th to 20th	Day	26% 22% 30% 17% 4 1	300
	21st to end	Day	28% 19% 32% 19% 2	225
March	1st to 10th	Day	20% 17% 43% 16% 4	270
	11th to 20th	Day	27% 16% 38% 14% 5%	270
	21st to end	Day	28% 14% 32% 21% 5%	474
April	1st to 10th	Day	17% 15% 33% 25% 9% 1	460
	11th to 20th	Day	20% 17% 27% 22% 12% 2	452
	21st to end	Day	18% 15% 36% 20% 10% 2	460
May	1st to 10th	Day	17% 14% 27% 30% 9% 2	463
	11th to 20th	Day	16% 9% 24% 28% 18% 5%	546
	21st to end	Day	9% 6% 29% 30% 18% 9%	734
June	1st to 10th	Day	9% 4 18% 30% 27% 11%	680
	11th to 20th	Day	8% 2 19% 34% 28% 9%	680
	21st to end	Day	6% 6% 23% 35% 23% 7%	680
July	1st to 10th	Day	11% 3 12% 27% 28% 20%	671
	11th to 20th	Day	6% 3 12% 35% 30% 13%	668
	21st to end	Day	8% 1 12% 33% 33% 12%	739
August	1st to 10th	Day	8% 2 12% 32% 32% 14%	591
	11th to 20th	Day	10% 3 15% 29% 30% 13%	479
	21st to end	Day	9% 1 11% 26% 36% 17%	539
September	1st to 10th	Day	11% 3 17% 25% 29% 15%	490
	11th to 20th	Day	7% 3 10% 28% 38% 15%	490
	21st to end	Day	12% 6% 21% 26% 24% 11%	490
October	1st to 10th	Day	10% 6% 22% 35% 21% 7%	391
	11th to 20th	Day	14% 14% 32% 24% 12% 5%	300
	21st to end	Day	26% 16% 29% 20% 8%	330
November	1st to 10th	Day	13% 9% 36% 22% 14% 5%	300
	11th to 20th	Day	19% 17% 32% 19% 10% 3	300
	21st to end	Day	24% 14% 30% 22% 8% 2	300
December	1st to 10th	Day	13% 20% 39% 17% 5% 6%	300
	11th to 20th	Day	22% 16% 34% 21% 6% 1	300
	21st to end	Day	28% 18% 34% 16% 4	330
January	1st to 10th	Night	20% 14% 37% 24% 4	1000
	11th to 20th	Night	22% 17% 35% 23% 4	1000
	21st to end	Night	20% 14% 39% 25% 2	1100
February	1st to 10th	Night	21% 12% 40% 24% 2	933
	11th to 20th	Night	21% 16% 37% 23% 2	783
	21st to end	Night	24% 15% 38% 22% 2	629
March	1st to 10th	Night	20% 15% 38% 23% 4	760
	11th to 20th	Night	22% 12% 34% 26% 6%	651
	21st to end	Night	23% 9% 33% 28% 7%	627
April	1st to 10th	Night	16% 13% 36% 28% 6%	570
	11th to 20th	Night	18% 9% 33% 29% 11% 1	563
	21st to end	Night	21% 7% 36% 26% 8% 1	570
May	1st to 10th	Night	17% 7% 30% 35% 11%	570
	11th to 20th	Night	11% 6% 27% 35% 18% 2	561
	21st to end	Night	10% 3 22% 39% 23% 3	617
June	1st to 10th	Night	10% 3 18% 41% 26% 2	570
	11th to 20th	Night	7% 2 17% 47% 25% 2	570
	21st to end	Night	6% 2 20% 42% 28% 1	570
July	1st to 10th	Night	11% 2 8% 34% 37% 8%	555
	11th to 20th	Night	5% 2 13% 40% 36% 3	552
	21st to end	Night	5% 1 12% 41% 36% 4	624
August	1st to 10th	Night	8% 2 10% 41% 35% 5%	567
	11th to 20th	Night	7% 1 14% 39% 34% 5%	564
	21st to end	Night	8% 1 8% 36% 43% 4	627
September	1st to 10th	Night	11% 2 14% 36% 32% 6%	570
	11th to 20th	Night	8% 2 13% 37% 34% 6%	632
	21st to end	Night	12% 5% 21% 32% 24% 6%	760
October	1st to 10th	Night	8% 4 23% 37% 23% 4	760
	11th to 20th	Night	15% 9% 29% 30% 15% 1	760
	21st to end	Night	22% 10% 31% 30% 7%	836
November	1st to 10th	Night	13% 7% 36% 34% 10% 1	780
	11th to 20th	Night	17% 11% 34% 29% 10% 1	800
	21st to end	Night	24% 11% 32% 26% 7%	800
December	1st to 10th	Night	21% 13% 34% 27% 6%	975
	11th to 20th	Night	24% 7% 33% 31% 5%	1000
	21st to end	Night	28% 13% 34% 21% 4	1100

Page generated at 2025-02-18 02:26:28. Version ac07

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