Lone Wolf Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lone Wolf Observatory 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	12% 9% 3 8% 5% 4 5% 4 6% 7% 37%	131456
	Night	13% 10% 4 8% 5% 4 4 3 5% 6% 38%	130633
Transparency	Day	44% 6% 12% 23% 14% 2	134976
	Night	45% 5% 11% 22% 14% 2	135188
Seeing	Day	16% 10% 29% 25% 15% 5%	17616
	Night	17% 10% 31% 30% 12% 1	27601

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	11% 12% 7% 13% 5% 6% 5% 4 6% 7% 24%	4691
	11th to 20th	Day	8% 9% 5% 14% 8% 7% 6% 4 6% 5% 27%	4710
	21st to end	Day	12% 14% 6% 10% 7% 5% 4 3 5% 6% 27%	5614
February	1st to 10th	Day	15% 12% 4 11% 6% 4 4 4 5% 6% 28%	1890
	11th to 20th	Day	14% 10% 4 9% 7% 5% 5% 4 5% 5% 33%	2042
	21st to end	Day	12% 15% 4 12% 5% 3 3 3 5% 5% 32%	1730
March	1st to 10th	Day	19% 13% 3 6% 3 3 3 2 3 4 41%	4580
	11th to 20th	Day	8% 7% 3 6% 5% 4 5% 4 6% 7% 44%	4901
	21st to end	Day	19% 11% 4 10% 5% 5% 5% 4 5% 6% 26%	6043
April	1st to 10th	Day	16% 13% 4 7% 4 4 4 3 5% 6% 34%	2412
	11th to 20th	Day	17% 9% 3 8% 4 4 4 4 5% 6% 37%	2374
	21st to end	Day	19% 9% 3 8% 5% 4 5% 4 5% 6% 34%	2420
May	1st to 10th	Day	17% 8% 3 7% 5% 4 5% 4 6% 9% 34%	5862
	11th to 20th	Day	14% 7% 2 6% 4 4 4 4 5% 8% 41%	6289
	21st to end	Day	12% 7% 2 7% 5% 4 5% 4 7% 8% 38%	6935
June	1st to 10th	Day	9% 5% 2 6% 4 5% 5% 5% 6% 8% 45%	2800
	11th to 20th	Day	8% 5% 3 6% 5% 5% 5% 4 6% 8% 45%	2800
	21st to end	Day	9% 6% 2 6% 6% 5% 5% 5% 6% 8% 41%	2800
July	1st to 10th	Day	9% 6% 3 7% 5% 5% 5% 5% 7% 11% 39%	6360
	11th to 20th	Day	9% 6% 2 6% 5% 5% 5% 5% 7% 10% 40%	6360
	21st to end	Day	10% 7% 3 7% 5% 5% 5% 5% 6% 9% 37%	6924
August	1st to 10th	Day	6% 5% 2 6% 4 5% 5% 5% 7% 10% 44%	4350
	11th to 20th	Day	10% 5% 2 6% 4 4 5% 5% 7% 11% 42%	3849
	21st to end	Day	5% 5% 2 6% 4 4 5% 4 7% 9% 49%	4312
September	1st to 10th	Day	10% 5% 3 4 4 4 4 4 6% 7% 50%	2400
	11th to 20th	Day	10% 4 1 4 3 3 4 3 5% 8% 53%	2320
	21st to end	Day	8% 7% 3 6% 5% 4 5% 4 6% 7% 47%	2200
October	1st to 10th	Day	11% 8% 2 6% 4 4 4 3 4 7% 49%	2073
	11th to 20th	Day	16% 8% 2 7% 4 4 4 3 5% 6% 43%	2000
	21st to end	Day	18% 9% 2 6% 4 4 4 3 5% 6% 39%	2045
November	1st to 10th	Day	11% 9% 3 6% 3 3 3 3 5% 7% 47%	1852
	11th to 20th	Day	16% 12% 4 7% 4 3 4 4 3 6% 36%	1890
	21st to end	Day	17% 14% 4 8% 4 4 3 2 4 5% 35%	1780
December	1st to 10th	Day	8% 9% 4 9% 5% 3 4 3 4 5% 45%	2690
	11th to 20th	Day	13% 15% 6% 12% 6% 5% 5% 4 6% 6% 22%	3088
	21st to end	Day	25% 20% 7% 13% 5% 3 4 3 3 4 13%	4070
January	1st to 10th	Night	12% 14% 5% 12% 5% 4 3 3 4 4 31%	8232
	11th to 20th	Night	10% 12% 5% 14% 9% 7% 5% 4 6% 4 25%	8280
	21st to end	Night	14% 13% 5% 9% 5% 5% 4 3 4 5% 34%	8584
February	1st to 10th	Night	15% 11% 5% 10% 6% 4 4 3 5% 5% 32%	2730
	11th to 20th	Night	13% 11% 4 9% 6% 5% 4 3 4 6% 37%	2463
	21st to end	Night	16% 12% 4 8% 4 4 3 3 4 5% 37%	2076
March	1st to 10th	Night	16% 12% 4 7% 4 3 3 3 4 4 40%	5493
	11th to 20th	Night	12% 7% 3 5% 5% 4 4 3 5% 7% 45%	5310
	21st to end	Night	17% 12% 5% 10% 5% 5% 5% 4 5% 5% 27%	5126
April	1st to 10th	Night	16% 10% 3 6% 4 4 4 3 6% 6% 39%	2010
	11th to 20th	Night	17% 9% 2 6% 4 4 4 3 4 6% 42%	1975
	21st to end	Night	17% 8% 3 7% 4 4 3 4 6% 8% 37%	1979
May	1st to 10th	Night	17% 10% 3 8% 5% 4 4 3 6% 7% 33%	4033
	11th to 20th	Night	12% 6% 2 6% 4 4 5% 4 8% 9% 40%	3610
	21st to end	Night	12% 8% 3 7% 4 5% 4 4 5% 8% 39%	3942
June	1st to 10th	Night	9% 5% 2 6% 3 5% 4 4 4 8% 50%	1600
	11th to 20th	Night	9% 5% 2 6% 5% 5% 5% 3 6% 10% 46%	1600
	21st to end	Night	8% 5% 2 5% 5% 5% 5% 5% 5% 8% 46%	1600
July	1st to 10th	Night	9% 6% 3 7% 5% 4 5% 4 7% 9% 42%	3618
	11th to 20th	Night	6% 5% 2 6% 3 4 5% 3 5% 9% 50%	3617
	21st to end	Night	9% 7% 2 7% 5% 5% 4 5% 6% 8% 41%	3947
August	1st to 10th	Night	5% 4 2 5% 4 3 6% 4 6% 8% 52%	2806
	11th to 20th	Night	6% 5% 2 6% 4 4 5% 4 8% 9% 49%	3200
	21st to end	Night	5% 4 2 5% 4 4 4 4 6% 9% 53%	3586
September	1st to 10th	Night	10% 5% 2 5% 3 3 4 3 4 6% 56%	2000
	11th to 20th	Night	8% 3 1 5% 3 4 4 4 5% 8% 54%	2058
	21st to end	Night	9% 5% 2 6% 4 5% 4 4 6% 9% 47%	2200
October	1st to 10th	Night	9% 6% 2 6% 4 4 3 3 4 6% 53%	2324
	11th to 20th	Night	14% 7% 2 5% 3 3 3 3 5% 6% 48%	2400
	21st to end	Night	18% 9% 3 6% 4 4 3 3 4 6% 39%	2794
November	1st to 10th	Night	11% 7% 2 5% 4 3 3 3 5% 6% 49%	2666
	11th to 20th	Night	13% 10% 3 7% 5% 4 4 3 5% 6% 40%	2730
	21st to end	Night	16% 10% 4 9% 4 3 4 3 4 5% 38%	2835
December	1st to 10th	Night	11% 9% 3 7% 4 4 4 3 5% 6% 43%	4720
	11th to 20th	Night	15% 13% 5% 10% 5% 3 3 3 4 5% 32%	5339
	21st to end	Night	23% 18% 7% 11% 5% 5% 4 3 4 4 16%	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	59% 4 13% 17% 6% 1	4692
	11th to 20th	Day	56% 5% 7% 16% 13% 2	4710
	21st to end	Day	58% 4 13% 18% 7% 1	5614
February	1st to 10th	Day	57% 5% 13% 17% 7% 2	1890
	11th to 20th	Day	51% 6% 12% 20% 9% 2	2052
	21st to end	Day	55% 4 9% 22% 8% 2	1730
March	1st to 10th	Day	49% 4 8% 23% 13% 3	4580
	11th to 20th	Day	37% 6% 11% 32% 14% 1	4901
	21st to end	Day	57% 7% 12% 17% 6% 1	6045
April	1st to 10th	Day	50% 5% 12% 21% 11%	2412
	11th to 20th	Day	47% 5% 10% 24% 11% 3	2374
	21st to end	Day	49% 6% 12% 19% 12% 2	2420
May	1st to 10th	Day	45% 6% 11% 22% 14% 1	5897
	11th to 20th	Day	40% 7% 10% 28% 12% 3	6293
	21st to end	Day	39% 7% 12% 23% 15% 3	6949
June	1st to 10th	Day	34% 7% 13% 27% 17% 3	2800
	11th to 20th	Day	35% 7% 11% 22% 22% 3	2800
	21st to end	Day	39% 9% 12% 22% 16% 2	2800
July	1st to 10th	Day	37% 7% 14% 26% 14% 1	6291
	11th to 20th	Day	36% 7% 15% 27% 14% 1	6285
	21st to end	Day	40% 8% 18% 20% 12% 2	6728
August	1st to 10th	Day	32% 7% 19% 29% 13% 1	4335
	11th to 20th	Day	34% 6% 15% 28% 15% 1	3885
	21st to end	Day	30% 6% 12% 32% 16% 3	4311
September	1st to 10th	Day	33% 6% 11% 25% 20% 5%	2400
	11th to 20th	Day	29% 5% 11% 27% 24% 4	2320
	21st to end	Day	36% 6% 10% 26% 21% 2	2200
October	1st to 10th	Day	25% 3 6% 28% 36% 2	3372
	11th to 20th	Day	29% 4 10% 23% 31% 3	3240
	21st to end	Day	41% 4 8% 26% 18% 3	3283
November	1st to 10th	Day	37% 4 14% 27% 15% 3	1852
	11th to 20th	Day	49% 4 10% 23% 12% 1	1890
	21st to end	Day	52% 4 10% 24% 9%	1780
December	1st to 10th	Day	42% 3 13% 33% 9% 1	2690
	11th to 20th	Day	61% 5% 11% 17% 5%	3085
	21st to end	Day	76% 4 8% 7% 4	4070
January	1st to 10th	Night	55% 5% 13% 20% 6%	8233
	11th to 20th	Night	60% 5% 10% 12% 13% 1	8280
	21st to end	Night	53% 4 11% 21% 11% 1	8584
February	1st to 10th	Night	53% 4 12% 18% 11% 1	2730
	11th to 20th	Night	49% 4 10% 23% 11% 1	2464
	21st to end	Night	50% 4 10% 21% 13% 2	2076
March	1st to 10th	Night	47% 4 9% 24% 12% 4	5493
	11th to 20th	Night	38% 4 12% 27% 15% 3	5310
	21st to end	Night	57% 6% 9% 20% 7% 1	5126
April	1st to 10th	Night	45% 5% 11% 23% 13% 2	2010
	11th to 20th	Night	43% 4 9% 24% 14% 5%	1975
	21st to end	Night	44% 7% 12% 22% 12% 3	1979
May	1st to 10th	Night	48% 7% 11% 18% 14% 3	4060
	11th to 20th	Night	37% 8% 13% 24% 13% 4	3611
	21st to end	Night	41% 7% 12% 23% 14% 3	3950
June	1st to 10th	Night	32% 6% 13% 26% 19% 4	1600
	11th to 20th	Night	33% 6% 13% 23% 22% 3	1600
	21st to end	Night	35% 8% 15% 23% 17% 3	1600
July	1st to 10th	Night	37% 7% 12% 26% 16% 2	3580
	11th to 20th	Night	31% 6% 14% 27% 21% 1	3572
	21st to end	Night	38% 8% 15% 20% 15% 3	3832
August	1st to 10th	Night	27% 7% 18% 28% 18% 2	2797
	11th to 20th	Night	30% 7% 16% 28% 17% 1	3230
	21st to end	Night	28% 6% 12% 33% 18% 3	3586
September	1st to 10th	Night	29% 4 10% 27% 25% 5%	2000
	11th to 20th	Night	27% 5% 11% 28% 24% 5%	2058
	21st to end	Night	33% 6% 13% 25% 21% 3	2200
October	1st to 10th	Night	22% 4 7% 31% 33% 4	3805
	11th to 20th	Night	28% 4 9% 23% 33% 4	3899
	21st to end	Night	39% 4 9% 23% 21% 4	4506
November	1st to 10th	Night	35% 5% 11% 28% 18% 4	2666
	11th to 20th	Night	45% 4 12% 22% 15% 2	2730
	21st to end	Night	50% 4 10% 23% 13% 1	2835
December	1st to 10th	Night	42% 4 13% 30% 11% 1	4720
	11th to 20th	Night	54% 4 12% 19% 10%	5341
	21st to end	Night	71% 5% 8% 11% 4	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	19% 16% 34% 26% 5%	330
	11th to 20th	Day	22% 22% 40% 11% 4 1	330
	21st to end	Day	19% 22% 35% 18% 6%	363
February	1st to 10th	Day	20% 18% 39% 19% 3 1	330
	11th to 20th	Day	22% 19% 38% 16% 5%	330
	21st to end	Day	22% 18% 47% 11% 3	273
March	1st to 10th	Day	23% 22% 36% 16% 2	330
	11th to 20th	Day	25% 18% 35% 15% 5%	330
	21st to end	Day	29% 15% 37% 12% 5% 1	564
April	1st to 10th	Day	25% 14% 32% 23% 5% 1	504
	11th to 20th	Day	22% 18% 28% 19% 11% 2	492
	21st to end	Day	24% 13% 33% 21% 8% 1	500
May	1st to 10th	Day	20% 11% 34% 24% 9% 2	503
	11th to 20th	Day	22% 10% 30% 22% 13% 3	708
	21st to end	Day	16% 10% 30% 23% 14% 7%	789
June	1st to 10th	Day	9% 6% 28% 29% 22% 5%	730
	11th to 20th	Day	8% 5% 29% 33% 22% 4	730
	21st to end	Day	10% 8% 32% 29% 16% 5%	730
July	1st to 10th	Day	10% 3 18% 31% 23% 14%	721
	11th to 20th	Day	11% 4 21% 31% 23% 10%	718
	21st to end	Day	9% 3 20% 37% 25% 6%	794
August	1st to 10th	Day	6% 3 20% 34% 26% 11%	716
	11th to 20th	Day	10% 5% 16% 28% 29% 13%	519
	21st to end	Day	6% 2 19% 32% 31% 9%	583
September	1st to 10th	Day	12% 5% 19% 28% 29% 7%	530
	11th to 20th	Day	9% 3 15% 30% 30% 13%	530
	21st to end	Day	10% 9% 26% 25% 22% 8%	530
October	1st to 10th	Day	15% 5% 26% 31% 20% 3	403
	11th to 20th	Day	18% 20% 32% 22% 8% 1	330
	21st to end	Day	31% 12% 30% 21% 5% 1	363
November	1st to 10th	Day	15% 15% 38% 20% 8% 3	330
	11th to 20th	Day	23% 16% 36% 16% 8% 1	330
	21st to end	Day	24% 14% 36% 22% 4	330
December	1st to 10th	Day	15% 17% 42% 19% 6% 1	330
	11th to 20th	Day	21% 17% 35% 22% 4 1	330
	21st to end	Day	28% 18% 39% 13% 2	363
January	1st to 10th	Night	18% 14% 40% 23% 5%	1050
	11th to 20th	Night	20% 15% 40% 20% 5%	1050
	21st to end	Night	21% 13% 37% 26% 3	1155
February	1st to 10th	Night	22% 13% 38% 23% 4	1050
	11th to 20th	Night	19% 14% 36% 27% 4	828
	21st to end	Night	23% 14% 40% 20% 3	692
March	1st to 10th	Night	21% 16% 35% 23% 5%	840
	11th to 20th	Night	19% 11% 35% 28% 6%	733
	21st to end	Night	24% 12% 37% 20% 6% 1	693
April	1st to 10th	Night	21% 13% 34% 26% 5%	603
	11th to 20th	Night	22% 14% 31% 26% 7%	593
	21st to end	Night	20% 10% 32% 30% 7%	600
May	1st to 10th	Night	20% 7% 35% 30% 7% 2	600
	11th to 20th	Night	18% 6% 30% 34% 10% 1	591
	21st to end	Night	13% 4 30% 35% 16% 1	650
June	1st to 10th	Night	10% 4 24% 46% 16% 1	600
	11th to 20th	Night	11% 4 24% 45% 16% 1	600
	21st to end	Night	9% 2 32% 38% 18% 1	600
July	1st to 10th	Night	8% 2 15% 40% 31% 4	585
	11th to 20th	Night	7% 2 18% 43% 27% 3	582
	21st to end	Night	6% 1 16% 47% 29% 2	657
August	1st to 10th	Night	6% 2 17% 42% 29% 4	597
	11th to 20th	Night	7% 1 13% 43% 31% 5%	594
	21st to end	Night	7% 2 15% 41% 32% 2	660
September	1st to 10th	Night	12% 4 18% 35% 28% 3	600
	11th to 20th	Night	10% 3 18% 37% 29% 3	658
	21st to end	Night	10% 8% 25% 33% 24% 2	800
October	1st to 10th	Night	11% 6% 27% 35% 20% 2	800
	11th to 20th	Night	20% 11% 32% 25% 12% 1	800
	21st to end	Night	24% 11% 33% 25% 6%	880
November	1st to 10th	Night	16% 11% 38% 26% 9% 1	820
	11th to 20th	Night	18% 15% 36% 26% 5%	840
	21st to end	Night	22% 13% 35% 24% 6%	945
December	1st to 10th	Night	21% 13% 38% 24% 5%	1050
	11th to 20th	Night	22% 13% 33% 27% 5%	1050
	21st to end	Night	29% 15% 33% 21% 3	1155

Page generated at 2026-03-30 01:18:40. Version ac07

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