Observatorio De Solitario
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatorio De Solitario clear sky chart from 2005-11-06 to 2025-05-11.

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	3 2 1 3 2 3 3 3 5% 7% 68%	118234
	Night	3 2 1 3 3 3 3 3 5% 7% 65%	119577
Transparency	Day	16% 5% 8% 19% 26% 26%	118020
	Night	17% 6% 9% 19% 24% 26%	119380
Seeing	Day	5% 6% 20% 34% 27% 8%	15014
	Night	5% 4 20% 46% 24% 1	25303

By Month

Percentage Cloud Cover SW (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	3 2 1 2 2 2 2 2 4 6% 75%	4537
	11th to 20th	Day	3 3 1 2 2 2 2 2 4 5% 75%	4540
	21st to end	Day	3 4 2 4 3 3 3 3 4 6% 66%	4994
February	1st to 10th	Day	3 4 1 4 4 3 3 3 5% 4 67%	2000
	11th to 20th	Day	4 5% 2 4 3 3 3 2 4 6% 64%	1949
	21st to end	Day	3 3 1 2 3 3 3 3 5% 6% 68%	1650
March	1st to 10th	Day	2 3 1 3 3 3 4 3 5% 6% 66%	4500
	11th to 20th	Day	6% 3 1 2 2 2 2 3 4 6% 69%	4788
	21st to end	Day	2 3 1 3 3 3 3 3 5% 7% 66%	5959
April	1st to 10th	Day	2 2 1 3 3 3 3 3 5% 6% 68%	2400
	11th to 20th	Day	3 3 1 2 2 3 3 3 5% 6% 70%	2371
	21st to end	Day	4 3 1 3 3 2 2 2 5% 5% 72%	2400
May	1st to 10th	Day	1 1 1 2 2 2 2 2 3 6% 78%	3920
	11th to 20th	Day	2 2 1 2 2 2 2 3 4 6% 73%	3766
	21st to end	Day	1 1 1 2 1 2 2 2 5% 6% 76%	4319
June	1st to 10th	Day	1 1 2 2 2 4 4 6% 8% 70%	2470
	11th to 20th	Day	3 2 1 3 3 3 4 3 5% 7% 66%	2470
	21st to end	Day	3 2 1 3 2 4 4 3 7% 10% 61%	2386
July	1st to 10th	Day	3 2 1 4 3 3 4 4 6% 9% 61%	3800
	11th to 20th	Day	2 2 1 2 3 4 4 5% 6% 11% 59%	3800
	21st to end	Day	3 2 1 4 4 4 4 4 7% 10% 57%	4118
August	1st to 10th	Day	2 2 2 2 3 3 4 7% 11% 65%	3784
	11th to 20th	Day	3 2 1 4 3 4 4 4 7% 10% 59%	3726
	21st to end	Day	2 2 1 4 3 3 4 5% 7% 11% 57%	4180
September	1st to 10th	Day	5% 5% 2 6% 4 5% 5% 5% 7% 9% 47%	2280
	11th to 20th	Day	8% 5% 2 4 4 4 5% 4 5% 8% 53%	2147
	21st to end	Day	5% 3 1 4 3 3 3 3 5% 7% 62%	2090
October	1st to 10th	Day	2 2 1 1 2 2 2 2 4 5% 79%	3480
	11th to 20th	Day	4 1 1 2 2 2 2 3 4 5% 74%	3336
	21st to end	Day	4 1 1 1 1 1 1 1 2 3 83%	3438
November	1st to 10th	Day	5% 2 1 2 1 1 2 2 3 5% 74%	1923
	11th to 20th	Day	4 3 1 2 2 2 2 3 4 7% 69%	1800
	21st to end	Day	6% 2 1 3 3 3 3 3 4 7% 64%	1800
December	1st to 10th	Day	7% 6% 2 6% 4 3 3 2 4 8% 57%	2940
	11th to 20th	Day	2 3 1 4 3 3 3 3 4 6% 68%	3391
	21st to end	Day	2 2 2 2 2 2 2 4 5% 75%	4782
January	1st to 10th	Night	2 2 1 2 1 2 2 2 4 6% 76%	5428
	11th to 20th	Night	3 1 2 2 2 3 2 4 5% 75%	5440
	21st to end	Night	5% 3 2 4 3 3 4 3 5% 7% 61%	5984
February	1st to 10th	Night	4 3 1 4 3 3 3 3 4 6% 66%	2400
	11th to 20th	Night	5% 4 1 4 3 3 4 3 4 7% 62%	2338
	21st to end	Night	4 3 1 3 3 3 4 3 4 6% 66%	1980
March	1st to 10th	Night	3 4 2 4 3 3 3 3 5% 6% 64%	5374
	11th to 20th	Night	7% 3 1 2 2 2 2 3 4 5% 69%	5186
	21st to end	Night	3 3 1 4 3 3 3 3 5% 6% 67%	4992
April	1st to 10th	Night	4 4 1 3 3 3 3 4 5% 6% 64%	2000
	11th to 20th	Night	3 2 1 2 3 3 3 3 5% 7% 68%	1977
	21st to end	Night	3 3 1 2 3 4 3 3 4 5% 71%	2000
May	1st to 10th	Night	2 1 1 2 2 2 2 2 4 6% 75%	3270
	11th to 20th	Night	5% 2 1 3 3 3 3 3 4 6% 66%	3145
	21st to end	Night	2 2 1 3 3 3 4 3 5% 7% 68%	3260
June	1st to 10th	Night	2 2 1 3 3 4 5% 5% 9% 10% 57%	1710
	11th to 20th	Night	2 2 1 4 4 5% 5% 4 8% 10% 55%	1710
	21st to end	Night	3 3 1 4 3 4 4 4 7% 10% 57%	1785
July	1st to 10th	Night	2 2 1 3 3 5% 5% 5% 9% 13% 52%	3170
	11th to 20th	Night	2 1 1 2 2 3 4 4 8% 12% 61%	3170
	21st to end	Night	2 2 1 3 3 4 5% 5% 8% 11% 57%	3445
August	1st to 10th	Night	1 1 1 2 3 3 4 4 9% 14% 58%	3155
	11th to 20th	Night	2 2 1 3 3 3 5% 5% 7% 13% 56%	3113
	21st to end	Night	2 2 1 3 4 4 5% 5% 9% 12% 54%	3487
September	1st to 10th	Night	5% 4 2 4 5% 4 5% 4 7% 10% 50%	1900
	11th to 20th	Night	6% 4 2 7% 4 5% 6% 5% 7% 10% 46%	2032
	21st to end	Night	4 5% 1 4 4 4 5% 5% 6% 9% 52%	2090
October	1st to 10th	Night	2 1 1 2 2 2 3 3 3 6% 76%	3480
	11th to 20th	Night	4 2 1 3 2 2 3 3 5% 6% 70%	3581
	21st to end	Night	3 2 1 1 1 1 1 1 2 4 82%	4120
November	1st to 10th	Night	6% 2 1 2 1 1 2 2 3 5% 76%	2352
	11th to 20th	Night	4 2 1 3 3 3 2 3 4 6% 71%	2600
	21st to end	Night	5% 3 1 3 3 3 3 3 5% 5% 66%	2600
December	1st to 10th	Night	6% 3 3 6% 4 5% 5% 5% 5% 7% 51%	4250
	11th to 20th	Night	2 3 1 3 2 2 3 3 4 6% 71%	4816
	21st to end	Night	2 2 1 3 2 2 3 2 5% 6% 72%	6237

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	13% 3 4 21% 30% 29%	4538
	11th to 20th	Day	13% 2 5% 18% 36% 25%	4540
	21st to end	Day	20% 4 5% 20% 32% 19%	4994
February	1st to 10th	Day	21% 3 5% 14% 24% 34%	2000
	11th to 20th	Day	22% 4 7% 14% 24% 28%	1959
	21st to end	Day	16% 4 5% 12% 27% 36%	1650
March	1st to 10th	Day	18% 4 4 10% 21% 43%	4500
	11th to 20th	Day	16% 4 5% 10% 18% 47%	4788
	21st to end	Day	16% 4 5% 8% 24% 43%	5959
April	1st to 10th	Day	16% 5% 6% 11% 23% 39%	2400
	11th to 20th	Day	14% 5% 6% 13% 22% 39%	2374
	21st to end	Day	15% 4 5% 13% 24% 40%	2400
May	1st to 10th	Day	10% 4 5% 13% 20% 48%	3920
	11th to 20th	Day	12% 5% 8% 13% 23% 38%	3769
	21st to end	Day	8% 5% 8% 18% 20% 42%	4319
June	1st to 10th	Day	9% 6% 11% 24% 29% 20%	2470
	11th to 20th	Day	17% 5% 8% 16% 31% 23%	2470
	21st to end	Day	18% 7% 13% 23% 24% 15%	2386
July	1st to 10th	Day	18% 8% 17% 31% 20% 6%	3741
	11th to 20th	Day	16% 6% 15% 36% 21% 7%	3737
	21st to end	Day	18% 7% 15% 29% 22% 9%	3988
August	1st to 10th	Day	13% 5% 12% 31% 33% 7%	3772
	11th to 20th	Day	19% 7% 14% 37% 20% 3	3762
	21st to end	Day	19% 8% 17% 28% 21% 5%	4179
September	1st to 10th	Day	30% 10% 16% 19% 15% 11%	2280
	11th to 20th	Day	29% 7% 13% 18% 23% 10%	2147
	21st to end	Day	21% 7% 10% 21% 25% 15%	2090
October	1st to 10th	Day	9% 5% 7% 15% 24% 40%	3480
	11th to 20th	Day	14% 4 9% 20% 18% 34%	3336
	21st to end	Day	9% 2 3 12% 42% 32%	3438
November	1st to 10th	Day	14% 4 8% 19% 30% 25%	1923
	11th to 20th	Day	16% 4 8% 21% 29% 22%	1800
	21st to end	Day	21% 4 8% 21% 24% 22%	1800
December	1st to 10th	Day	28% 4 7% 19% 25% 17%	2940
	11th to 20th	Day	17% 4 5% 24% 31% 20%	3389
	21st to end	Day	12% 4 4 14% 38% 29%	4782
January	1st to 10th	Night	12% 3 3 16% 37% 29%	5428
	11th to 20th	Night	13% 3 6% 15% 28% 36%	5440
	21st to end	Night	22% 6% 5% 18% 29% 21%	5984
February	1st to 10th	Night	20% 3 5% 14% 24% 34%	2400
	11th to 20th	Night	22% 4 8% 14% 23% 29%	2338
	21st to end	Night	18% 5% 5% 10% 26% 35%	1980
March	1st to 10th	Night	19% 4 4 10% 21% 42%	5374
	11th to 20th	Night	17% 7% 6% 9% 17% 44%	5186
	21st to end	Night	16% 4 6% 10% 21% 42%	4992
April	1st to 10th	Night	20% 5% 6% 13% 19% 37%	2000
	11th to 20th	Night	15% 5% 8% 15% 18% 38%	1977
	21st to end	Night	15% 5% 8% 17% 22% 34%	2000
May	1st to 10th	Night	10% 4 7% 16% 18% 45%	3270
	11th to 20th	Night	16% 9% 10% 15% 16% 35%	3146
	21st to end	Night	13% 7% 10% 19% 17% 34%	3261
June	1st to 10th	Night	16% 7% 14% 28% 22% 13%	1710
	11th to 20th	Night	21% 9% 10% 16% 28% 17%	1710
	21st to end	Night	19% 7% 15% 22% 22% 14%	1785
July	1st to 10th	Night	18% 9% 23% 32% 16% 3	3120
	11th to 20th	Night	12% 5% 17% 40% 20% 5%	3110
	21st to end	Night	17% 8% 16% 32% 24% 4	3336
August	1st to 10th	Night	13% 6% 13% 34% 32% 3	3144
	11th to 20th	Night	16% 7% 18% 41% 16% 2	3143
	21st to end	Night	19% 11% 18% 30% 18% 4	3487
September	1st to 10th	Night	27% 10% 16% 24% 14% 10%	1900
	11th to 20th	Night	29% 11% 15% 18% 18% 8%	2032
	21st to end	Night	24% 8% 14% 22% 17% 15%	2090
October	1st to 10th	Night	10% 5% 8% 14% 24% 39%	3480
	11th to 20th	Night	15% 5% 10% 19% 16% 34%	3581
	21st to end	Night	10% 2 4 16% 38% 30%	4120
November	1st to 10th	Night	14% 4 7% 17% 31% 28%	2352
	11th to 20th	Night	16% 5% 7% 19% 26% 27%	2600
	21st to end	Night	20% 5% 10% 15% 23% 28%	2600
December	1st to 10th	Night	28% 9% 7% 18% 18% 20%	4250
	11th to 20th	Night	15% 3 5% 22% 32% 23%	4817
	21st to end	Night	13% 4 5% 12% 40% 27%	6237

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	10% 6% 29% 38% 16% 2	300
	11th to 20th	Day	5% 9% 25% 42% 17% 2	300
	21st to end	Day	4 14% 29% 33% 18% 2	330
February	1st to 10th	Day	6% 10% 22% 32% 24% 6%	300
	11th to 20th	Day	9% 13% 26% 35% 15% 2	300
	21st to end	Day	6% 14% 34% 36% 9% 2	249
March	1st to 10th	Day	8% 10% 32% 35% 15% 1	300
	11th to 20th	Day	8% 16% 35% 28% 10% 4	405
	21st to end	Day	7% 17% 34% 31% 9% 1	550
April	1st to 10th	Day	6% 15% 38% 31% 9% 2	500
	11th to 20th	Day	4 16% 40% 30% 8% 2	492
	21st to end	Day	6% 12% 36% 36% 9% 1	500
May	1st to 10th	Day	4 9% 38% 36% 11% 3	503
	11th to 20th	Day	2 8% 35% 36% 17% 2	489
	21st to end	Day	2 5% 26% 45% 21% 1	629
June	1st to 10th	Day	2 2 16% 40% 36% 5%	680
	11th to 20th	Day	3 1 12% 39% 40% 5%	680
	21st to end	Day	3 2 11% 36% 42% 8%	596
July	1st to 10th	Day	4 1 8% 29% 38% 19%	486
	11th to 20th	Day	2 6% 36% 40% 15%	484
	21st to end	Day	2 1 6% 37% 41% 13%	531
August	1st to 10th	Day	4 4 26% 47% 19%	487
	11th to 20th	Day	3 1 7% 27% 42% 19%	477
	21st to end	Day	2 1 7% 31% 38% 21%	539
September	1st to 10th	Day	6% 2 8% 34% 37% 14%	490
	11th to 20th	Day	6% 5% 23% 48% 17%	357
	21st to end	Day	8% 1 8% 24% 40% 19%	300
October	1st to 10th	Day	4 2 10% 27% 42% 15%	300
	11th to 20th	Day	9% 2 12% 33% 32% 13%	300
	21st to end	Day	8% 4 16% 29% 32% 11%	330
November	1st to 10th	Day	6% 4 19% 31% 31% 9%	300
	11th to 20th	Day	8% 7% 20% 26% 30% 8%	300
	21st to end	Day	7% 10% 23% 33% 23% 4	300
December	1st to 10th	Day	9% 6% 18% 34% 28% 6%	300
	11th to 20th	Day	5% 8% 26% 37% 22% 2	300
	21st to end	Day	4 7% 24% 44% 20% 2	330
January	1st to 10th	Night	7% 3 21% 51% 17% 1	800
	11th to 20th	Night	8% 4 21% 48% 19% 1	800
	21st to end	Night	6% 6% 27% 48% 13% 1	880
February	1st to 10th	Night	5% 6% 25% 44% 20% 1	800
	11th to 20th	Night	6% 5% 27% 51% 10% 1	784
	21st to end	Night	6% 7% 32% 49% 6%	660
March	1st to 10th	Night	7% 6% 35% 40% 10% 1	800
	11th to 20th	Night	9% 8% 29% 40% 14% 1	800
	21st to end	Night	4 8% 36% 41% 10%	668
April	1st to 10th	Night	4 9% 33% 45% 9%	600
	11th to 20th	Night	4 8% 38% 44% 6%	593
	21st to end	Night	4 9% 35% 45% 7%	600
May	1st to 10th	Night	4 5% 31% 51% 9% 1	600
	11th to 20th	Night	5% 6% 29% 50% 10%	563
	21st to end	Night	3 2 30% 51% 13%	617
June	1st to 10th	Night	2 2 18% 57% 20% 1	570
	11th to 20th	Night	2 1 17% 59% 21%	570
	21st to end	Night	4 1 12% 50% 34% 1	570
July	1st to 10th	Night	5% 1 11% 44% 37% 2	555
	11th to 20th	Night	3 6% 46% 43% 2	552
	21st to end	Night	3 1 6% 39% 48% 2	624
August	1st to 10th	Night	2 1 5% 34% 58% 2	567
	11th to 20th	Night	4 1 5% 31% 54% 4	564
	21st to end	Night	3 1 6% 36% 51% 3	627
September	1st to 10th	Night	5% 2 5% 38% 48% 2	570
	11th to 20th	Night	7% 1 10% 38% 43% 1	570
	21st to end	Night	6% 1 11% 40% 39% 2	570
October	1st to 10th	Night	4 1 12% 45% 37% 1	570
	11th to 20th	Night	7% 1 15% 49% 26% 2	641
	21st to end	Night	5% 4 14% 42% 32% 4	836
November	1st to 10th	Night	7% 2 12% 45% 32% 3	792
	11th to 20th	Night	4 4 15% 50% 26% 2	1000
	21st to end	Night	6% 5% 24% 44% 20% 2	1000
December	1st to 10th	Night	7% 4 16% 50% 22% 2	1000
	11th to 20th	Night	5% 4 23% 49% 19% 1	1000
	21st to end	Night	5% 4 22% 51% 16% 1	990

Page generated at 2025-05-08 08:34:01. Version ac07

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