Kaladar
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kaladar clear sky chart from 2005-11-06 to 2025-02-25.

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	16% 10% 3 8% 5% 4 4 4 5% 7% 33%	108787
	Night	16% 11% 4 8% 5% 4 4 3 5% 6% 32%	109840
Transparency	Day	49% 7% 12% 20% 10% 1	112365
	Night	50% 7% 12% 19% 10% 1	114426
Seeing	Day	22% 17% 31% 19% 8% 3	14735
	Night	22% 14% 31% 24% 9% 1	24096

By Month

Percentage Cloud Cover NE (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% 13% 5% 11% 6% 5% 4 4 6% 6% 28%	3597
	11th to 20th	Day	11% 19% 8% 14% 5% 5% 5% 3 4 4 21%	3570
	21st to end	Day	14% 18% 7% 16% 6% 5% 4 3 3 4 20%	4374
February	1st to 10th	Day	13% 17% 4 12% 6% 6% 5% 4 5% 6% 23%	1800
	11th to 20th	Day	13% 14% 4 13% 6% 5% 4 3 3 5% 28%	1753
	21st to end	Day	18% 15% 4 10% 7% 5% 4 4 4 5% 23%	1564
March	1st to 10th	Day	21% 13% 4 8% 5% 4 3 2 4 5% 29%	3262
	11th to 20th	Day	10% 17% 5% 10% 6% 5% 4 3 5% 5% 31%	3480
	21st to end	Day	14% 10% 3 6% 4 3 3 3 5% 6% 44%	3932
April	1st to 10th	Day	20% 14% 4 8% 4 4 4 3 4 5% 32%	2280
	11th to 20th	Day	21% 9% 2 5% 4 4 3 3 4 6% 37%	2254
	21st to end	Day	21% 9% 3 8% 6% 4 4 3 4 5% 32%	2420
May	1st to 10th	Day	20% 8% 2 7% 5% 4 4 4 6% 6% 33%	4362
	11th to 20th	Day	16% 9% 4 8% 5% 5% 4 3 6% 8% 33%	4398
	21st to end	Day	13% 6% 3 6% 4 4 5% 5% 5% 8% 41%	4837
June	1st to 10th	Day	19% 8% 3 7% 6% 5% 5% 4 6% 7% 29%	2660
	11th to 20th	Day	16% 5% 2 6% 5% 4 6% 4 7% 8% 37%	2660
	21st to end	Day	18% 8% 2 7% 5% 5% 5% 3 6% 8% 33%	2660
July	1st to 10th	Day	12% 5% 2 7% 6% 5% 6% 4 7% 10% 36%	4440
	11th to 20th	Day	12% 5% 2 5% 4 4 5% 4 7% 10% 41%	4440
	21st to end	Day	8% 6% 2 7% 5% 6% 6% 5% 7% 9% 40%	4814
August	1st to 10th	Day	16% 8% 3 7% 5% 4 5% 4 6% 8% 35%	4150
	11th to 20th	Day	17% 7% 2 6% 4 5% 5% 4 7% 9% 34%	4044
	21st to end	Day	13% 6% 2 7% 4 4 4 5% 7% 10% 39%	4198
September	1st to 10th	Day	13% 7% 2 6% 4 4 5% 4 6% 7% 42%	2280
	11th to 20th	Day	11% 6% 2 6% 4 4 4 3 4 7% 48%	2280
	21st to end	Day	19% 6% 2 6% 4 5% 4 3 6% 8% 38%	1998
October	1st to 10th	Day	19% 9% 3 7% 4 3 4 4 5% 7% 35%	1900
	11th to 20th	Day	21% 9% 3 8% 5% 5% 4 4 6% 7% 29%	1900
	21st to end	Day	25% 12% 3 8% 5% 4 5% 3 4 5% 26%	2016
November	1st to 10th	Day	15% 8% 3 9% 5% 4 5% 4 5% 7% 34%	1718
	11th to 20th	Day	18% 12% 4 9% 5% 4 4 3 5% 6% 30%	1600
	21st to end	Day	23% 14% 4 8% 5% 4 5% 4 5% 6% 22%	1600
December	1st to 10th	Day	21% 17% 4 11% 5% 5% 4 4 4 6% 19%	2600
	11th to 20th	Day	17% 21% 6% 10% 5% 4 3 3 4 4 24%	2986
	21st to end	Day	23% 18% 3 10% 5% 4 3 2 3 4 24%	3960
January	1st to 10th	Night	15% 14% 7% 13% 6% 5% 5% 3 5% 5% 23%	6349
	11th to 20th	Night	11% 15% 7% 14% 9% 6% 6% 3 5% 5% 18%	6315
	21st to end	Night	15% 16% 7% 14% 6% 4 4 3 4 5% 21%	6564
February	1st to 10th	Night	13% 16% 5% 11% 6% 5% 5% 4 6% 6% 25%	2600
	11th to 20th	Night	13% 14% 6% 9% 6% 5% 5% 3 5% 5% 28%	2533
	21st to end	Night	15% 13% 5% 8% 5% 5% 5% 3 6% 6% 29%	1984
March	1st to 10th	Night	19% 11% 4 8% 5% 4 4 3 5% 5% 32%	3578
	11th to 20th	Night	16% 15% 5% 8% 5% 4 4 4 6% 6% 26%	3479
	21st to end	Night	15% 9% 3 7% 4 4 4 3 5% 7% 39%	3700
April	1st to 10th	Night	20% 10% 3 7% 4 3 4 3 5% 5% 35%	1900
	11th to 20th	Night	19% 8% 2 8% 4 4 4 3 5% 5% 38%	1875
	21st to end	Night	19% 9% 3 6% 4 5% 5% 3 5% 7% 34%	1777
May	1st to 10th	Night	21% 10% 3 6% 3 4 3 4 6% 6% 33%	2562
	11th to 20th	Night	17% 8% 3 7% 5% 4 4 3 5% 6% 38%	2495
	21st to end	Night	13% 6% 2 5% 4 5% 5% 3 5% 6% 45%	2738
June	1st to 10th	Night	15% 7% 3 7% 6% 5% 6% 4 6% 8% 34%	1520
	11th to 20th	Night	11% 7% 2 5% 5% 4 4 4 5% 10% 43%	1520
	21st to end	Night	15% 6% 3 6% 6% 4 5% 3 5% 8% 39%	1520
July	1st to 10th	Night	9% 5% 2 7% 6% 5% 6% 5% 7% 8% 40%	2520
	11th to 20th	Night	14% 5% 2 6% 3 4 3 3 5% 8% 48%	2520
	21st to end	Night	11% 6% 2 5% 4 4 4 4 6% 7% 47%	2739
August	1st to 10th	Night	12% 6% 2 6% 4 4 5% 4 6% 7% 44%	2775
	11th to 20th	Night	14% 6% 2 5% 5% 4 4 3 6% 7% 45%	2785
	21st to end	Night	10% 5% 2 6% 5% 4 5% 4 7% 10% 43%	3412
September	1st to 10th	Night	11% 6% 2 5% 4 4 4 3 6% 8% 47%	1900
	11th to 20th	Night	12% 5% 1 5% 4 3 3 3 6% 7% 52%	1900
	21st to end	Night	17% 5% 2 6% 4 4 5% 3 5% 6% 43%	2179
October	1st to 10th	Night	16% 7% 3 8% 4 4 4 3 5% 6% 39%	2280
	11th to 20th	Night	21% 8% 3 8% 6% 4 4 4 5% 6% 32%	2280
	21st to end	Night	21% 11% 3 7% 5% 4 5% 3 4 7% 29%	2580
November	1st to 10th	Night	18% 9% 3 6% 4 4 4 4 5% 6% 36%	2577
	11th to 20th	Night	18% 11% 3 7% 6% 4 5% 4 4 6% 32%	2800
	21st to end	Night	20% 13% 4 9% 4 5% 5% 4 6% 5% 26%	2800
December	1st to 10th	Night	20% 15% 4 10% 6% 5% 6% 4 5% 6% 19%	4580
	11th to 20th	Night	21% 16% 5% 9% 6% 4 4 3 4 5% 24%	5208
	21st to end	Night	26% 17% 4 10% 5% 4 3 3 4 4 20%	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	52% 9% 11% 18% 8% 1	3598
	11th to 20th	Day	66% 6% 11% 11% 7%	3600
	21st to end	Day	69% 4 8% 9% 9% 1	4374
February	1st to 10th	Day	61% 6% 10% 16% 6% 1	1800
	11th to 20th	Day	59% 6% 10% 15% 9% 1	1762
	21st to end	Day	63% 6% 8% 11% 10% 1	1564
March	1st to 10th	Day	56% 5% 13% 15% 10% 1	3265
	11th to 20th	Day	52% 9% 13% 15% 9% 2	3480
	21st to end	Day	40% 5% 10% 26% 15% 4	3932
April	1st to 10th	Day	56% 4 8% 18% 12% 3	2280
	11th to 20th	Day	48% 6% 9% 21% 15% 2	2254
	21st to end	Day	54% 5% 8% 15% 14% 4	2420
May	1st to 10th	Day	48% 8% 11% 21% 10% 2	4376
	11th to 20th	Day	47% 9% 14% 19% 10% 2	4402
	21st to end	Day	37% 10% 13% 22% 15% 2	4837
June	1st to 10th	Day	50% 9% 11% 17% 12% 1	2660
	11th to 20th	Day	42% 8% 13% 23% 13% 2	2660
	21st to end	Day	47% 7% 14% 18% 12% 1	2660
July	1st to 10th	Day	41% 7% 15% 24% 12% 1	4370
	11th to 20th	Day	36% 7% 16% 32% 10%	4365
	21st to end	Day	38% 7% 14% 29% 11%	4661
August	1st to 10th	Day	46% 7% 14% 22% 11%	4136
	11th to 20th	Day	44% 6% 15% 26% 8% 1	4083
	21st to end	Day	39% 7% 14% 30% 10% 1	4198
September	1st to 10th	Day	39% 8% 13% 27% 13% 1	2280
	11th to 20th	Day	34% 7% 13% 30% 15% 1	2280
	21st to end	Day	43% 8% 13% 26% 10%	1998
October	1st to 10th	Day	43% 6% 12% 30% 8% 1	3160
	11th to 20th	Day	46% 5% 15% 24% 10% 1	3140
	21st to end	Day	52% 6% 14% 20% 7%	3306
November	1st to 10th	Day	47% 10% 14% 20% 9% 1	1718
	11th to 20th	Day	55% 6% 12% 17% 10% 1	1600
	21st to end	Day	60% 9% 12% 10% 8%	1600
December	1st to 10th	Day	66% 6% 16% 8% 3	2600
	11th to 20th	Day	64% 6% 10% 13% 7%	2986
	21st to end	Day	65% 4 8% 15% 7%	3960
January	1st to 10th	Night	60% 8% 10% 14% 7%	6349
	11th to 20th	Night	65% 8% 12% 10% 5%	6360
	21st to end	Night	63% 7% 9% 9% 12% 1	6564
February	1st to 10th	Night	58% 7% 12% 17% 6%	2600
	11th to 20th	Night	56% 6% 10% 19% 8% 1	2535
	21st to end	Night	54% 6% 12% 18% 9% 1	1984
March	1st to 10th	Night	52% 6% 10% 20% 10% 1	3588
	11th to 20th	Night	53% 10% 14% 15% 7% 1	3480
	21st to end	Night	40% 6% 12% 24% 15% 3	3700
April	1st to 10th	Night	51% 4 8% 20% 14% 2	1900
	11th to 20th	Night	47% 7% 9% 19% 16% 1	1875
	21st to end	Night	48% 7% 10% 16% 15% 3	1777
May	1st to 10th	Night	48% 8% 12% 17% 12% 3	2568
	11th to 20th	Night	43% 11% 13% 23% 9% 2	2496
	21st to end	Night	36% 8% 14% 20% 19% 2	2739
June	1st to 10th	Night	45% 9% 13% 20% 12% 1	1520
	11th to 20th	Night	36% 8% 14% 21% 19% 2	1520
	21st to end	Night	43% 8% 15% 20% 13% 1	1520
July	1st to 10th	Night	40% 6% 15% 22% 16% 1	2480
	11th to 20th	Night	37% 6% 13% 33% 12%	2472
	21st to end	Night	35% 7% 16% 29% 13% 1	2651
August	1st to 10th	Night	38% 6% 15% 26% 13% 1	2765
	11th to 20th	Night	38% 6% 15% 31% 10% 1	2812
	21st to end	Night	35% 8% 16% 29% 11% 1	3412
September	1st to 10th	Night	34% 8% 14% 28% 14% 1	1900
	11th to 20th	Night	31% 8% 15% 32% 14% 1	1900
	21st to end	Night	41% 7% 12% 28% 11% 1	2179
October	1st to 10th	Night	38% 7% 10% 27% 18%	3800
	11th to 20th	Night	43% 6% 16% 26% 9%	3779
	21st to end	Night	49% 6% 14% 24% 8%	4240
November	1st to 10th	Night	47% 6% 15% 22% 9% 1	2577
	11th to 20th	Night	51% 7% 13% 19% 10% 2	2800
	21st to end	Night	58% 9% 13% 16% 5%	2800
December	1st to 10th	Night	65% 6% 14% 13% 3	4580
	11th to 20th	Night	63% 5% 10% 13% 8%	5208
	21st to end	Night	66% 6% 7% 11% 9%	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% 24% 33% 16% 4	200
	11th to 20th	Day	29% 21% 32% 14% 5% 1	200
	21st to end	Day	25% 24% 35% 14% 3	310
February	1st to 10th	Day	30% 30% 28% 11% 1	300
	11th to 20th	Day	30% 28% 36% 5%	300
	21st to end	Day	35% 21% 33% 10% 1	352
March	1st to 10th	Day	26% 21% 35% 15% 4	460
	11th to 20th	Day	26% 22% 34% 14% 4	460
	21st to end	Day	33% 20% 28% 13% 5% 1	506
April	1st to 10th	Day	28% 23% 30% 13% 5%	460
	11th to 20th	Day	31% 23% 21% 15% 7% 2	452
	21st to end	Day	28% 22% 32% 11% 6% 2	460
May	1st to 10th	Day	24% 18% 30% 18% 7% 3	463
	11th to 20th	Day	16% 17% 36% 21% 7% 3	487
	21st to end	Day	16% 17% 34% 20% 9% 3	529
June	1st to 10th	Day	23% 12% 36% 20% 6% 2	490
	11th to 20th	Day	14% 19% 31% 22% 12% 1	490
	21st to end	Day	21% 13% 33% 21% 9% 2	490
July	1st to 10th	Day	12% 11% 31% 30% 14% 2	485
	11th to 20th	Day	14% 10% 32% 27% 14% 3	484
	21st to end	Day	13% 9% 35% 29% 11% 3	532
August	1st to 10th	Day	14% 8% 29% 30% 14% 5%	486
	11th to 20th	Day	13% 7% 28% 30% 17% 5%	479
	21st to end	Day	14% 11% 33% 24% 12% 7%	539
September	1st to 10th	Day	15% 13% 30% 23% 12% 7%	490
	11th to 20th	Day	12% 10% 26% 22% 18% 12%	490
	21st to end	Day	20% 12% 28% 23% 12% 6%	490
October	1st to 10th	Day	24% 18% 26% 16% 12% 4	490
	11th to 20th	Day	24% 23% 28% 17% 6% 1	490
	21st to end	Day	30% 20% 28% 18% 3	499
November	1st to 10th	Day	30% 15% 28% 20% 6%	352
	11th to 20th	Day	28% 20% 37% 9% 6% 1	200
	21st to end	Day	30% 21% 34% 12% 3 1	200
December	1st to 10th	Day	32% 19% 34% 12% 4 1	200
	11th to 20th	Day	36% 26% 27% 10% 2 1	200
	21st to end	Day	33% 20% 31% 11% 4	220
January	1st to 10th	Night	27% 18% 34% 19% 4	800
	11th to 20th	Night	26% 18% 33% 19% 5% 1	800
	21st to end	Night	20% 16% 35% 24% 4 1	880
February	1st to 10th	Night	23% 20% 38% 18% 2	800
	11th to 20th	Night	22% 19% 39% 16% 3	783
	21st to end	Night	24% 19% 35% 18% 3	647
March	1st to 10th	Night	23% 18% 36% 21% 3	760
	11th to 20th	Night	25% 20% 30% 21% 3 1	760
	21st to end	Night	22% 15% 35% 19% 7% 1	836
April	1st to 10th	Night	25% 16% 34% 21% 3	760
	11th to 20th	Night	23% 23% 28% 19% 7% 1	751
	21st to end	Night	24% 14% 29% 24% 10%	637
May	1st to 10th	Night	25% 10% 26% 29% 8% 2	415
	11th to 20th	Night	14% 10% 34% 34% 8%	374
	21st to end	Night	12% 8% 39% 28% 12%	411
June	1st to 10th	Night	17% 7% 36% 30% 9%	380
	11th to 20th	Night	13% 10% 31% 33% 11% 1	380
	21st to end	Night	18% 6% 28% 37% 12%	380
July	1st to 10th	Night	6% 8% 31% 39% 16% 1	370
	11th to 20th	Night	13% 3 27% 38% 19% 1	368
	21st to end	Night	12% 3 29% 43% 13%	416
August	1st to 10th	Night	13% 4 27% 34% 22% 1	530
	11th to 20th	Night	11% 5% 22% 35% 24% 3	564
	21st to end	Night	13% 6% 29% 32% 17% 2	798
September	1st to 10th	Night	13% 5% 33% 30% 17% 3	760
	11th to 20th	Night	14% 6% 24% 27% 26% 4	760
	21st to end	Night	19% 10% 23% 28% 18% 2	760
October	1st to 10th	Night	20% 14% 26% 24% 14% 2	760
	11th to 20th	Night	25% 15% 29% 23% 8% 1	760
	21st to end	Night	27% 15% 31% 22% 5%	836
November	1st to 10th	Night	25% 13% 29% 24% 8% 1	780
	11th to 20th	Night	25% 16% 34% 18% 7% 1	800
	21st to end	Night	30% 17% 29% 19% 6%	800
December	1st to 10th	Night	30% 18% 31% 18% 4	800
	11th to 20th	Night	26% 20% 35% 17% 2 1	800
	21st to end	Night	34% 15% 31% 17% 3	880

Page generated at 2025-02-22 06:51:34. Version ac07

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