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 2026-07-01.

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% 5% 4 4 5% 7% 33%	138346
	Night	16% 11% 4 8% 5% 4 4 3 5% 6% 32%	133948
Transparency	Day	50% 6% 12% 20% 11% 1	141877
	Night	51% 6% 12% 19% 11% 1	138505
Seeing	Day	23% 17% 31% 19% 8% 2	16506
	Night	22% 14% 31% 24% 9% 1	25717

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	14% 13% 5% 11% 6% 5% 5% 4 6% 6% 25%	4661
	11th to 20th	Day	11% 22% 8% 14% 6% 5% 5% 3 3 4 18%	4650
	21st to end	Day	11% 16% 7% 17% 7% 8% 5% 3 4 4 19%	5660
February	1st to 10th	Day	13% 16% 3 12% 6% 6% 5% 4 5% 6% 23%	1890
	11th to 20th	Day	13% 14% 4 13% 6% 5% 4 3 4 5% 27%	1843
	21st to end	Day	18% 15% 4 10% 7% 6% 4 3 5% 5% 23%	1682
March	1st to 10th	Day	19% 13% 4 9% 5% 4 4 2 4 5% 29%	4782
	11th to 20th	Day	12% 14% 4 8% 6% 5% 5% 4 5% 6% 31%	5090
	21st to end	Day	19% 12% 3 7% 4 3 3 2 4 5% 38%	5762
April	1st to 10th	Day	20% 13% 4 8% 4 4 4 3 4 5% 32%	2520
	11th to 20th	Day	22% 10% 2 6% 4 4 3 3 4 6% 36%	2494
	21st to end	Day	21% 10% 3 8% 5% 4 4 3 4 5% 33%	2675
May	1st to 10th	Day	21% 8% 3 7% 5% 5% 5% 4 5% 6% 30%	8118
	11th to 20th	Day	16% 8% 3 7% 5% 5% 4 4 5% 7% 35%	8221
	21st to end	Day	19% 8% 3 6% 4 4 5% 4 5% 7% 36%	9060
June	1st to 10th	Day	19% 8% 3 7% 6% 5% 5% 4 6% 7% 31%	2940
	11th to 20th	Day	16% 5% 2 6% 5% 4 6% 4 7% 8% 36%	2940
	21st to end	Day	17% 8% 2 7% 5% 5% 4 4 6% 8% 34%	2940
July	1st to 10th	Day	13% 6% 2 7% 5% 5% 5% 4 7% 9% 36%	6360
	11th to 20th	Day	10% 5% 2 6% 4 4 5% 4 6% 9% 43%	6360
	21st to end	Day	8% 5% 2 6% 4 5% 5% 4 7% 9% 44%	6926
August	1st to 10th	Day	16% 7% 3 7% 5% 4 5% 4 6% 8% 36%	4282
	11th to 20th	Day	17% 7% 2 6% 4 5% 5% 4 6% 9% 35%	4174
	21st to end	Day	13% 6% 2 7% 4 4 4 5% 7% 10% 40%	4331
September	1st to 10th	Day	13% 7% 2 7% 4 4 5% 4 5% 7% 43%	2400
	11th to 20th	Day	11% 6% 2 6% 4 4 4 3 4 7% 49%	2400
	21st to end	Day	19% 6% 2 6% 4 4 4 3 6% 8% 38%	2103
October	1st to 10th	Day	19% 9% 3 7% 4 3 4 4 5% 6% 36%	2000
	11th to 20th	Day	20% 9% 3 8% 5% 5% 4 4 6% 7% 29%	2000
	21st to end	Day	25% 11% 3 7% 5% 4 5% 3 4 5% 27%	2122
November	1st to 10th	Day	16% 9% 3 9% 5% 4 5% 4 5% 7% 34%	1806
	11th to 20th	Day	17% 12% 4 9% 5% 4 4 3 5% 6% 29%	1680
	21st to end	Day	22% 15% 4 8% 5% 4 5% 4 5% 6% 23%	1680
December	1st to 10th	Day	21% 18% 4 11% 5% 5% 4 4 4 5% 19%	2680
	11th to 20th	Day	17% 20% 6% 10% 5% 4 3 3 4 4 24%	3066
	21st to end	Day	23% 18% 3 10% 5% 4 3 2 3 4 24%	4048
January	1st to 10th	Night	14% 14% 7% 14% 6% 6% 5% 3 5% 5% 21%	8234
	11th to 20th	Night	11% 19% 6% 14% 8% 6% 5% 3 5% 5% 17%	8235
	21st to end	Night	12% 14% 6% 12% 7% 5% 5% 4 5% 6% 24%	8503
February	1st to 10th	Night	13% 15% 4 11% 6% 5% 5% 4 6% 6% 26%	2730
	11th to 20th	Night	13% 14% 6% 9% 6% 5% 4 3 6% 5% 27%	2663
	21st to end	Night	15% 14% 4 8% 5% 5% 5% 4 6% 7% 28%	2123
March	1st to 10th	Night	19% 13% 4 9% 5% 5% 4 3 5% 4 30%	5264
	11th to 20th	Night	13% 12% 4 7% 5% 5% 5% 4 7% 9% 30%	5089
	21st to end	Night	19% 10% 3 8% 4 4 4 3 5% 6% 35%	5411
April	1st to 10th	Night	20% 10% 4 7% 4 3 4 3 5% 6% 33%	2100
	11th to 20th	Night	19% 9% 2 8% 4 4 4 3 5% 5% 38%	2075
	21st to end	Night	19% 9% 3 6% 4 5% 4 3 5% 7% 34%	1963
May	1st to 10th	Night	23% 9% 2 7% 4 4 4 4 6% 7% 29%	4764
	11th to 20th	Night	15% 8% 3 7% 4 3 4 3 5% 7% 41%	4639
	21st to end	Night	18% 6% 2 5% 4 4 5% 4 6% 7% 39%	5114
June	1st to 10th	Night	15% 6% 3 7% 6% 4 6% 3 6% 8% 36%	1680
	11th to 20th	Night	12% 7% 2 5% 5% 4 4 4 5% 10% 43%	1680
	21st to end	Night	15% 6% 3 6% 6% 4 5% 3 5% 8% 39%	1680
July	1st to 10th	Night	10% 6% 3 7% 6% 5% 6% 4 7% 9% 38%	3600
	11th to 20th	Night	12% 5% 2 6% 4 4 3 3 5% 8% 49%	3600
	21st to end	Night	9% 6% 2 5% 4 3 4 4 6% 7% 50%	3926
August	1st to 10th	Night	12% 6% 2 6% 4 4 5% 4 6% 7% 44%	2863
	11th to 20th	Night	14% 6% 2 5% 5% 4 3 3 6% 7% 45%	2875
	21st to end	Night	10% 5% 2 6% 5% 4 5% 4 7% 9% 43%	3520
September	1st to 10th	Night	11% 6% 2 6% 4 4 4 3 6% 8% 48%	2000
	11th to 20th	Night	11% 5% 1 5% 4 3 3 3 6% 7% 52%	2000
	21st to end	Night	17% 6% 2 6% 4 4 5% 3 5% 6% 43%	2294
October	1st to 10th	Night	16% 7% 3 7% 4 4 4 3 5% 6% 41%	2400
	11th to 20th	Night	21% 8% 3 8% 6% 4 4 4 5% 6% 32%	2400
	21st to end	Night	21% 10% 3 7% 5% 4 5% 3 4 7% 31%	2716
November	1st to 10th	Night	18% 9% 3 6% 5% 4 4 4 5% 6% 36%	2709
	11th to 20th	Night	18% 11% 3 8% 5% 4 4 4 4 6% 32%	2940
	21st to end	Night	20% 14% 4 9% 5% 5% 4 4 6% 5% 25%	2940
December	1st to 10th	Night	20% 15% 4 10% 5% 5% 6% 4 6% 6% 19%	4720
	11th to 20th	Night	20% 16% 5% 9% 6% 4 4 3 4 6% 24%	5348
	21st to end	Night	26% 17% 4 10% 5% 4 3 3 4 4 20%	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	57% 8% 12% 16% 7% 1	4662
	11th to 20th	Day	70% 5% 8% 9% 8%	4680
	21st to end	Day	69% 3 8% 10% 9% 1	5660
February	1st to 10th	Day	60% 6% 10% 16% 6% 1	1890
	11th to 20th	Day	59% 6% 9% 16% 9% 1	1852
	21st to end	Day	63% 6% 8% 12% 10% 1	1682
March	1st to 10th	Day	57% 4 11% 12% 14% 2	4785
	11th to 20th	Day	51% 7% 16% 15% 10% 2	5090
	21st to end	Day	49% 4 7% 21% 16% 3	5762
April	1st to 10th	Day	56% 4 8% 17% 13% 2	2520
	11th to 20th	Day	49% 5% 8% 20% 15% 2	2494
	21st to end	Day	54% 5% 8% 16% 14% 3	2675
May	1st to 10th	Day	53% 6% 9% 18% 11% 2	8129
	11th to 20th	Day	47% 7% 11% 19% 14% 1	8225
	21st to end	Day	46% 6% 10% 24% 12% 1	9061
June	1st to 10th	Day	49% 9% 10% 17% 14% 1	2940
	11th to 20th	Day	42% 7% 13% 23% 13% 2	2940
	21st to end	Day	46% 7% 15% 19% 12% 1	2940
July	1st to 10th	Day	42% 6% 14% 26% 12%	6290
	11th to 20th	Day	36% 6% 14% 28% 16%	6285
	21st to end	Day	35% 6% 14% 35% 11%	6728
August	1st to 10th	Day	45% 6% 14% 23% 11%	4268
	11th to 20th	Day	44% 6% 14% 27% 8% 1	4213
	21st to end	Day	39% 6% 14% 31% 10% 1	4331
September	1st to 10th	Day	39% 8% 13% 27% 12% 1	2400
	11th to 20th	Day	33% 7% 13% 31% 15% 1	2400
	21st to end	Day	44% 8% 13% 25% 10%	2103
October	1st to 10th	Day	42% 6% 12% 31% 9%	3260
	11th to 20th	Day	46% 5% 15% 23% 10% 1	3240
	21st to end	Day	52% 6% 14% 21% 8%	3412
November	1st to 10th	Day	48% 9% 14% 20% 8% 1	1806
	11th to 20th	Day	55% 6% 12% 16% 10% 1	1680
	21st to end	Day	61% 9% 12% 11% 8%	1680
December	1st to 10th	Day	66% 6% 15% 9% 3	2680
	11th to 20th	Day	64% 6% 10% 13% 7%	3066
	21st to end	Day	65% 4 8% 16% 7%	4048
January	1st to 10th	Night	63% 7% 10% 14% 6%	8234
	11th to 20th	Night	68% 6% 9% 9% 6%	8280
	21st to end	Night	60% 6% 8% 12% 13% 1	8503
February	1st to 10th	Night	57% 6% 12% 17% 6% 1	2730
	11th to 20th	Night	56% 6% 10% 19% 8% 1	2665
	21st to end	Night	54% 6% 12% 18% 9% 1	2123
March	1st to 10th	Night	56% 5% 8% 16% 11% 5%	5274
	11th to 20th	Night	47% 8% 18% 17% 8% 2	5090
	21st to end	Night	47% 5% 11% 21% 14% 2	5411
April	1st to 10th	Night	52% 4 8% 20% 13% 2	2100
	11th to 20th	Night	48% 6% 9% 20% 16% 1	2075
	21st to end	Night	48% 7% 9% 18% 15% 3	1963
May	1st to 10th	Night	52% 6% 10% 18% 11% 3	4770
	11th to 20th	Night	41% 7% 14% 23% 14% 1	4640
	21st to end	Night	43% 6% 13% 21% 16% 1	5115
June	1st to 10th	Night	45% 8% 12% 20% 15% 1	1680
	11th to 20th	Night	37% 7% 14% 22% 18% 2	1680
	21st to end	Night	43% 8% 15% 21% 12% 1	1680
July	1st to 10th	Night	41% 5% 17% 20% 16% 1	3560
	11th to 20th	Night	35% 5% 13% 33% 14%	3552
	21st to end	Night	33% 6% 13% 34% 14% 1	3809
August	1st to 10th	Night	38% 6% 15% 27% 13% 1	2853
	11th to 20th	Night	38% 6% 15% 31% 11% 1	2902
	21st to end	Night	35% 8% 16% 30% 11% 1	3520
September	1st to 10th	Night	34% 8% 14% 29% 14% 1	2000
	11th to 20th	Night	30% 8% 14% 33% 14% 1	2000
	21st to end	Night	41% 7% 12% 27% 12% 1	2294
October	1st to 10th	Night	37% 7% 10% 27% 18%	3920
	11th to 20th	Night	43% 6% 16% 26% 9%	3899
	21st to end	Night	48% 6% 14% 24% 8%	4376
November	1st to 10th	Night	47% 6% 15% 22% 9% 1	2709
	11th to 20th	Night	51% 6% 13% 19% 9% 1	2940
	21st to end	Night	58% 8% 12% 16% 5%	2940
December	1st to 10th	Night	65% 6% 14% 13% 3	4720
	11th to 20th	Night	63% 5% 10% 13% 8%	5348
	21st to end	Night	66% 6% 7% 11% 9%	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	24% 23% 34% 16% 3	220
	11th to 20th	Day	32% 20% 31% 13% 4	220
	21st to end	Day	25% 23% 35% 14% 3	341
February	1st to 10th	Day	29% 28% 29% 12% 2	330
	11th to 20th	Day	29% 27% 38% 6%	330
	21st to end	Day	34% 21% 34% 10% 1	398
March	1st to 10th	Day	26% 22% 34% 14% 3	540
	11th to 20th	Day	29% 22% 32% 13% 4	540
	21st to end	Day	34% 21% 28% 12% 5% 1	594
April	1st to 10th	Day	30% 23% 31% 12% 5%	540
	11th to 20th	Day	33% 23% 21% 15% 7% 2	532
	21st to end	Day	28% 21% 33% 11% 6% 1	540
May	1st to 10th	Day	24% 20% 30% 17% 6% 3	543
	11th to 20th	Day	17% 18% 37% 19% 7% 2	567
	21st to end	Day	20% 17% 34% 19% 8% 3	617
June	1st to 10th	Day	23% 13% 36% 20% 7% 2	570
	11th to 20th	Day	15% 18% 35% 20% 11% 1	570
	21st to end	Day	21% 14% 33% 22% 9% 2	570
July	1st to 10th	Day	12% 10% 32% 30% 14% 2	525
	11th to 20th	Day	14% 10% 32% 28% 14% 3	524
	21st to end	Day	12% 9% 36% 28% 11% 3	576
August	1st to 10th	Day	13% 8% 29% 31% 15% 4	526
	11th to 20th	Day	13% 6% 28% 30% 17% 5%	519
	21st to end	Day	14% 10% 33% 23% 12% 7%	583
September	1st to 10th	Day	15% 13% 28% 24% 13% 7%	530
	11th to 20th	Day	11% 10% 25% 24% 19% 12%	530
	21st to end	Day	20% 11% 28% 23% 12% 5%	530
October	1st to 10th	Day	23% 17% 26% 17% 12% 4	530
	11th to 20th	Day	23% 24% 29% 17% 5% 1	530
	21st to end	Day	29% 20% 29% 19% 3	539
November	1st to 10th	Day	31% 14% 29% 19% 6%	380
	11th to 20th	Day	28% 19% 37% 9% 6% 1	220
	21st to end	Day	31% 20% 35% 10% 3 1	220
December	1st to 10th	Day	30% 20% 34% 12% 3	220
	11th to 20th	Day	37% 25% 28% 9% 1 1	220
	21st to end	Day	34% 20% 31% 10% 4	242
January	1st to 10th	Night	26% 17% 34% 19% 3	840
	11th to 20th	Night	27% 18% 32% 18% 4	840
	21st to end	Night	21% 16% 35% 23% 4 1	924
February	1st to 10th	Night	22% 19% 37% 19% 3	840
	11th to 20th	Night	23% 18% 39% 17% 4	823
	21st to end	Night	24% 18% 35% 19% 3	692
March	1st to 10th	Night	24% 18% 35% 20% 3	840
	11th to 20th	Night	26% 19% 30% 21% 3 1	840
	21st to end	Night	23% 16% 35% 18% 7% 1	924
April	1st to 10th	Night	26% 17% 33% 21% 3	840
	11th to 20th	Night	23% 22% 28% 20% 6% 1	831
	21st to end	Night	24% 13% 30% 23% 9%	703
May	1st to 10th	Night	25% 11% 25% 29% 8% 2	459
	11th to 20th	Night	14% 11% 34% 33% 7%	414
	21st to end	Night	14% 8% 40% 27% 11%	455
June	1st to 10th	Night	17% 7% 35% 31% 9%	420
	11th to 20th	Night	14% 11% 32% 32% 10% 1	420
	21st to end	Night	17% 6% 28% 37% 11%	420
July	1st to 10th	Night	6% 7% 32% 38% 15% 1	390
	11th to 20th	Night	12% 3 27% 38% 19% 1	388
	21st to end	Night	12% 3 29% 43% 12%	438
August	1st to 10th	Night	12% 4 26% 34% 23% 1	558
	11th to 20th	Night	11% 4 22% 35% 25% 3	594
	21st to end	Night	13% 6% 29% 32% 17% 2	840
September	1st to 10th	Night	12% 5% 33% 30% 17% 2	800
	11th to 20th	Night	13% 5% 23% 29% 26% 4	800
	21st to end	Night	20% 9% 23% 28% 18% 2	800
October	1st to 10th	Night	19% 13% 26% 25% 15% 2	800
	11th to 20th	Night	25% 14% 30% 23% 7% 1	800
	21st to end	Night	26% 14% 31% 23% 5%	880
November	1st to 10th	Night	25% 14% 30% 24% 7%	820
	11th to 20th	Night	25% 16% 34% 18% 7% 1	840
	21st to end	Night	30% 17% 29% 19% 6%	840
December	1st to 10th	Night	30% 17% 30% 18% 4	840
	11th to 20th	Night	26% 20% 35% 16% 2 1	840
	21st to end	Night	34% 16% 30% 17% 3	924

Page generated at 2026-06-28 02:10:49. Version ac07

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