Malone
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Malone clear sky chart from 2005-11-06 to 2026-04-02.

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	17% 13% 4 10% 6% 5% 4 3 5% 6% 27%	131441
	Night	17% 15% 5% 11% 6% 5% 4 3 4 5% 25%	130409
Transparency	Day	57% 6% 10% 18% 8% 1	134884
	Night	61% 6% 9% 16% 8% 1	135053
Seeing	Day	27% 21% 29% 16% 6% 1	16283
	Night	27% 19% 28% 19% 7%	25437

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	11% 21% 9% 21% 8% 6% 4 3 3 4 10%	4661
	11th to 20th	Day	8% 19% 8% 22% 11% 7% 4 2 3 3 13%	4650
	21st to end	Day	9% 18% 7% 15% 10% 11% 5% 3 4 4 14%	5161
February	1st to 10th	Day	14% 20% 5% 16% 8% 5% 5% 4 4 4 16%	1890
	11th to 20th	Day	12% 17% 6% 16% 8% 5% 4 4 5% 4 19%	1939
	21st to end	Day	15% 20% 6% 11% 8% 5% 4 4 4 5% 18%	1730
March	1st to 10th	Day	19% 16% 6% 14% 6% 4 5% 3 4 4 22%	4576
	11th to 20th	Day	11% 19% 6% 10% 6% 4 4 4 4 5% 26%	4890
	21st to end	Day	18% 14% 5% 9% 5% 4 4 3 3 4 31%	6047
April	1st to 10th	Day	20% 18% 4 8% 5% 4 3 3 4 5% 28%	2412
	11th to 20th	Day	20% 14% 3 7% 4 4 4 3 3 5% 34%	2374
	21st to end	Day	23% 13% 3 6% 4 4 5% 3 4 5% 30%	2516
May	1st to 10th	Day	28% 13% 4 9% 5% 4 4 3 4 5% 21%	6290
	11th to 20th	Day	21% 11% 3 8% 5% 5% 5% 3 5% 7% 27%	6318
	21st to end	Day	23% 9% 3 7% 4 4 4 4 5% 6% 30%	6949
June	1st to 10th	Day	26% 8% 3 6% 5% 5% 5% 4 5% 6% 28%	2800
	11th to 20th	Day	18% 7% 2 6% 6% 4 5% 4 6% 8% 34%	2800
	21st to end	Day	24% 7% 2 7% 4 5% 4 4 6% 7% 29%	2800
July	1st to 10th	Day	14% 7% 3 7% 6% 6% 6% 5% 7% 8% 33%	6360
	11th to 20th	Day	12% 6% 2 6% 5% 5% 6% 5% 7% 8% 38%	6360
	21st to end	Day	14% 6% 2 6% 4 4 4 4 7% 10% 40%	6926
August	1st to 10th	Day	18% 8% 3 7% 5% 4 5% 4 7% 8% 31%	4563
	11th to 20th	Day	16% 7% 3 7% 6% 5% 4 4 5% 8% 35%	4045
	21st to end	Day	18% 6% 2 6% 4 4 4 4 6% 9% 37%	4312
September	1st to 10th	Day	16% 6% 2 6% 4 4 5% 4 5% 8% 42%	2400
	11th to 20th	Day	16% 6% 2 6% 3 4 3 3 4 6% 46%	2337
	21st to end	Day	18% 7% 2 7% 4 4 5% 4 6% 7% 36%	2200
October	1st to 10th	Day	21% 10% 3 5% 5% 5% 4 3 4 6% 33%	2034
	11th to 20th	Day	20% 13% 4 9% 5% 4 5% 3 5% 6% 28%	1995
	21st to end	Day	26% 16% 3 7% 4 3 3 3 4 6% 24%	1980
November	1st to 10th	Day	18% 16% 4 9% 5% 5% 4 4 5% 6% 27%	1851
	11th to 20th	Day	16% 19% 5% 9% 5% 5% 4 3 4 4 26%	1801
	21st to end	Day	18% 20% 6% 13% 5% 5% 5% 3 4 4 18%	1680
December	1st to 10th	Day	15% 23% 8% 18% 8% 5% 4 3 3 4 9%	2680
	11th to 20th	Day	16% 18% 6% 15% 6% 4 4 4 4 5% 19%	3066
	21st to end	Day	17% 18% 6% 13% 6% 4 3 3 4 5% 20%	4048
January	1st to 10th	Night	10% 22% 9% 22% 8% 4 3 2 3 4 13%	8234
	11th to 20th	Night	10% 20% 10% 22% 9% 5% 4 3 3 3 9%	8235
	21st to end	Night	11% 17% 6% 16% 10% 9% 5% 4 4 4 14%	9015
February	1st to 10th	Night	13% 18% 7% 18% 8% 6% 3 2 4 4 17%	2730
	11th to 20th	Night	12% 17% 6% 15% 8% 6% 4 3 3 4 21%	2566
	21st to end	Night	14% 18% 5% 13% 7% 4 4 3 3 5% 23%	2076
March	1st to 10th	Night	18% 16% 5% 11% 7% 5% 4 3 3 4 26%	5484
	11th to 20th	Night	14% 17% 5% 10% 5% 4 4 3 5% 6% 27%	5287
	21st to end	Night	16% 17% 6% 11% 5% 4 4 2 3 4 27%	5126
April	1st to 10th	Night	22% 15% 4 9% 5% 4 3 2 4 4 26%	2011
	11th to 20th	Night	22% 13% 4 7% 5% 4 4 3 4 5% 30%	1975
	21st to end	Night	23% 11% 3 7% 4 4 3 2 5% 6% 33%	1882
May	1st to 10th	Night	29% 13% 3 7% 4 4 5% 3 5% 6% 21%	3692
	11th to 20th	Night	24% 9% 3 7% 5% 4 4 3 5% 7% 29%	3575
	21st to end	Night	19% 11% 3 8% 5% 4 4 3 6% 7% 29%	3926
June	1st to 10th	Night	23% 8% 3 7% 4 4 5% 4 7% 8% 27%	1600
	11th to 20th	Night	18% 7% 2 6% 4 5% 3 4 6% 7% 38%	1600
	21st to end	Night	20% 8% 3 6% 5% 4 5% 4 6% 7% 33%	1600
July	1st to 10th	Night	15% 6% 3 7% 5% 6% 5% 4 6% 9% 35%	3600
	11th to 20th	Night	16% 7% 2 6% 4 4 4 4 6% 7% 42%	3600
	21st to end	Night	13% 7% 3 7% 5% 4 5% 4 6% 7% 40%	3926
August	1st to 10th	Night	18% 9% 3 7% 4 4 3 3 5% 7% 37%	2586
	11th to 20th	Night	18% 9% 3 8% 5% 4 4 3 5% 6% 36%	2967
	21st to end	Night	17% 7% 2 5% 4 3 5% 4 6% 8% 40%	3586
September	1st to 10th	Night	16% 6% 2 7% 5% 4 4 4 4 6% 42%	2000
	11th to 20th	Night	15% 5% 3 5% 3 3 3 3 5% 6% 47%	2062
	21st to end	Night	19% 7% 2 6% 3 4 4 4 5% 7% 39%	2200
October	1st to 10th	Night	21% 8% 2 6% 4 3 4 4 5% 6% 35%	2363
	11th to 20th	Night	20% 11% 3 8% 4 4 4 3 5% 6% 31%	2405
	21st to end	Night	27% 15% 3 8% 4 4 4 3 4 5% 24%	2860
November	1st to 10th	Night	21% 15% 3 8% 4 4 4 3 5% 5% 27%	2667
	11th to 20th	Night	18% 16% 5% 9% 5% 3 4 3 4 5% 27%	2815
	21st to end	Night	19% 19% 7% 11% 5% 5% 4 3 4 5% 19%	2940
December	1st to 10th	Night	15% 27% 12% 16% 5% 4 3 3 3 3 10%	4720
	11th to 20th	Night	19% 21% 7% 14% 5% 4 3 2 3 3 18%	5348
	21st to end	Night	19% 19% 5% 13% 5% 5% 5% 2 3 3 19%	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	78% 6% 7% 8% 2	4662
	11th to 20th	Day	77% 5% 5% 6% 6% 1	4680
	21st to end	Day	74% 4 7% 7% 7%	5161
February	1st to 10th	Day	72% 4 5% 14% 3 1	1890
	11th to 20th	Day	69% 5% 7% 12% 7% 1	1948
	21st to end	Day	69% 5% 6% 11% 7% 2	1730
March	1st to 10th	Day	66% 5% 7% 11% 8% 3	4579
	11th to 20th	Day	60% 6% 12% 12% 8% 2	4890
	21st to end	Day	58% 4 6% 14% 16% 2	6047
April	1st to 10th	Day	60% 5% 6% 18% 10% 2	2412
	11th to 20th	Day	55% 5% 5% 18% 15% 2	2374
	21st to end	Day	57% 6% 8% 16% 12% 3	2516
May	1st to 10th	Day	64% 7% 6% 15% 6% 1	6301
	11th to 20th	Day	55% 8% 12% 15% 9% 1	6322
	21st to end	Day	53% 7% 10% 20% 8% 1	6949
June	1st to 10th	Day	56% 7% 9% 17% 11% 1	2800
	11th to 20th	Day	47% 7% 10% 25% 9% 2	2800
	21st to end	Day	53% 8% 10% 19% 9% 1	2800
July	1st to 10th	Day	46% 7% 12% 26% 8%	6290
	11th to 20th	Day	41% 8% 13% 28% 11%	6285
	21st to end	Day	39% 7% 12% 36% 6%	6728
August	1st to 10th	Day	49% 7% 13% 22% 8%	4549
	11th to 20th	Day	48% 7% 14% 25% 6%	4086
	21st to end	Day	43% 7% 17% 22% 11%	4312
September	1st to 10th	Day	40% 7% 12% 29% 12% 1	2400
	11th to 20th	Day	39% 6% 10% 30% 14% 1	2337
	21st to end	Day	45% 8% 12% 23% 11% 1	2200
October	1st to 10th	Day	47% 6% 10% 26% 11%	3307
	11th to 20th	Day	52% 4 14% 21% 8% 1	3223
	21st to end	Day	51% 4 16% 23% 5% 1	3180
November	1st to 10th	Day	59% 7% 10% 17% 7%	1851
	11th to 20th	Day	62% 6% 9% 12% 8% 2	1801
	21st to end	Day	71% 5% 10% 9% 4	1680
December	1st to 10th	Day	81% 5% 6% 6% 2	2680
	11th to 20th	Day	68% 6% 8% 13% 5%	3066
	21st to end	Day	68% 4 8% 14% 7%	4048
January	1st to 10th	Night	77% 5% 7% 8% 3	8234
	11th to 20th	Night	80% 6% 5% 6% 4	8280
	21st to end	Night	74% 4 6% 9% 7% 1	9015
February	1st to 10th	Night	72% 5% 6% 11% 6%	2730
	11th to 20th	Night	67% 5% 7% 14% 6%	2568
	21st to end	Night	64% 5% 6% 15% 8% 1	2076
March	1st to 10th	Night	63% 4 6% 15% 11% 1	5494
	11th to 20th	Night	58% 5% 15% 13% 7% 2	5288
	21st to end	Night	62% 5% 4 16% 12% 1	5126
April	1st to 10th	Night	62% 5% 6% 16% 10% 1	2011
	11th to 20th	Night	58% 5% 8% 17% 11% 1	1975
	21st to end	Night	54% 5% 8% 18% 13% 3	1882
May	1st to 10th	Night	63% 8% 9% 13% 7% 1	3698
	11th to 20th	Night	52% 8% 10% 19% 10% 1	3576
	21st to end	Night	53% 6% 10% 20% 10% 1	3927
June	1st to 10th	Night	52% 7% 13% 17% 10% 1	1600
	11th to 20th	Night	45% 7% 13% 21% 13% 1	1600
	21st to end	Night	50% 7% 12% 22% 10%	1600
July	1st to 10th	Night	46% 6% 16% 23% 9%	3560
	11th to 20th	Night	41% 6% 15% 27% 11%	3552
	21st to end	Night	42% 8% 11% 30% 9%	3809
August	1st to 10th	Night	47% 6% 14% 24% 9%	2576
	11th to 20th	Night	48% 6% 17% 20% 7% 1	2992
	21st to end	Night	41% 7% 14% 24% 12% 1	3586
September	1st to 10th	Night	42% 7% 11% 28% 11%	2000
	11th to 20th	Night	37% 6% 12% 33% 12%	2062
	21st to end	Night	44% 7% 12% 23% 13% 1	2200
October	1st to 10th	Night	48% 6% 11% 24% 11% 1	3870
	11th to 20th	Night	51% 5% 12% 21% 10% 1	3916
	21st to end	Night	56% 5% 14% 18% 7% 1	4610
November	1st to 10th	Night	59% 7% 11% 15% 8% 1	2667
	11th to 20th	Night	60% 6% 9% 14% 7% 3	2815
	21st to end	Night	69% 6% 10% 11% 4	2940
December	1st to 10th	Night	82% 4 6% 7% 1	4720
	11th to 20th	Night	73% 5% 5% 11% 7%	5348
	21st to end	Night	71% 5% 6% 9% 8% 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	25% 29% 28% 15% 3	220
	11th to 20th	Day	30% 32% 30% 7% 1	220
	21st to end	Day	25% 29% 30% 13% 2	248
February	1st to 10th	Day	30% 36% 26% 7%	330
	11th to 20th	Day	31% 30% 32% 6% 1	426
	21st to end	Day	33% 28% 31% 8% 1	446
March	1st to 10th	Day	31% 29% 28% 9% 3	540
	11th to 20th	Day	31% 27% 30% 9% 2 1	540
	21st to end	Day	35% 25% 25% 10% 5% 1	594
April	1st to 10th	Day	36% 23% 26% 11% 4	504
	11th to 20th	Day	37% 20% 24% 13% 5% 1	492
	21st to end	Day	36% 19% 28% 10% 6% 1	500
May	1st to 10th	Day	32% 22% 26% 14% 4 2	503
	11th to 20th	Day	25% 21% 28% 18% 6% 2	527
	21st to end	Day	24% 21% 27% 21% 6%	573
June	1st to 10th	Day	30% 18% 30% 16% 5% 1	530
	11th to 20th	Day	19% 19% 34% 20% 7% 2	530
	21st to end	Day	26% 16% 34% 16% 6% 1	530
July	1st to 10th	Day	16% 14% 36% 22% 10% 1	525
	11th to 20th	Day	19% 16% 32% 25% 7% 2	524
	21st to end	Day	17% 13% 38% 24% 6% 1	576
August	1st to 10th	Day	19% 11% 29% 27% 11% 2	526
	11th to 20th	Day	19% 9% 31% 26% 10% 4	519
	21st to end	Day	20% 18% 28% 21% 9% 4	583
September	1st to 10th	Day	18% 16% 29% 21% 12% 4	530
	11th to 20th	Day	16% 12% 23% 25% 17% 6%	530
	21st to end	Day	19% 16% 29% 22% 11% 3	530
October	1st to 10th	Day	26% 16% 27% 17% 10% 4	530
	11th to 20th	Day	29% 22% 29% 13% 6% 1	527
	21st to end	Day	38% 21% 23% 16% 3	462
November	1st to 10th	Day	37% 19% 25% 13% 5%	425
	11th to 20th	Day	34% 28% 20% 11% 5% 1	341
	21st to end	Day	36% 27% 26% 10% 1	220
December	1st to 10th	Day	34% 25% 28% 11% 3	220
	11th to 20th	Day	32% 36% 24% 7% 1	220
	21st to end	Day	32% 25% 26% 14% 2 1	242
January	1st to 10th	Night	28% 26% 33% 11% 2	840
	11th to 20th	Night	30% 29% 26% 13% 2	840
	21st to end	Night	20% 27% 32% 16% 4	924
February	1st to 10th	Night	24% 27% 34% 13% 2	840
	11th to 20th	Night	25% 28% 31% 14% 2	823
	21st to end	Night	27% 24% 33% 14% 2	692
March	1st to 10th	Night	31% 24% 27% 16% 3	840
	11th to 20th	Night	29% 25% 28% 15% 3	840
	21st to end	Night	30% 22% 25% 17% 5%	924
April	1st to 10th	Night	31% 22% 27% 18% 2	805
	11th to 20th	Night	31% 20% 24% 18% 6%	791
	21st to end	Night	31% 17% 28% 17% 5% 1	682
May	1st to 10th	Night	34% 11% 28% 20% 7%	446
	11th to 20th	Night	26% 13% 30% 24% 7% 1	394
	21st to end	Night	20% 13% 31% 27% 8% 1	433
June	1st to 10th	Night	28% 11% 30% 25% 7% 1	400
	11th to 20th	Night	23% 10% 30% 28% 9% 1	400
	21st to end	Night	24% 11% 30% 27% 9%	400
July	1st to 10th	Night	13% 11% 31% 34% 11%	390
	11th to 20th	Night	12% 9% 31% 34% 14% 1	388
	21st to end	Night	17% 8% 32% 34% 9% 1	438
August	1st to 10th	Night	16% 7% 24% 36% 16%	398
	11th to 20th	Night	18% 7% 23% 33% 18% 2	645
	21st to end	Night	19% 9% 30% 30% 12% 1	880
September	1st to 10th	Night	20% 10% 28% 29% 11% 1	800
	11th to 20th	Night	18% 8% 22% 31% 20% 2	800
	21st to end	Night	23% 12% 25% 22% 18% 1	800
October	1st to 10th	Night	27% 13% 28% 20% 12% 1	800
	11th to 20th	Night	28% 17% 28% 21% 6%	800
	21st to end	Night	36% 19% 24% 19% 3	880
November	1st to 10th	Night	34% 19% 27% 15% 5%	820
	11th to 20th	Night	31% 22% 26% 13% 6% 2	840
	21st to end	Night	33% 25% 25% 13% 5%	840
December	1st to 10th	Night	33% 25% 27% 13% 3	840
	11th to 20th	Night	33% 27% 23% 13% 3 1	840
	21st to end	Night	35% 24% 27% 11% 3	924

Page generated at 2026-03-30 02:18:41. Version ac07

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