Zaug's Observing Site - Sangre De Cristo Ranches
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Zaug's Observing Site - Sangre De Cristo Ranches clear sky chart from 2005-11-06 to 2025-01-07.

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 5% 2 6% 4 4 5% 4 6% 8% 54%	108711
	Night	2 5% 2 5% 4 4 4 4 6% 7% 58%	109089
Transparency	Day	28% 6% 10% 24% 24% 8%	108463
	Night	26% 5% 11% 26% 25% 6%	108927
Seeing	Day	10% 24% 30% 24% 11% 2	15563
	Night	6% 19% 32% 29% 13% 1	25718

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	4 3 11% 6% 4 3 3 5% 8% 53%	2586
	11th to 20th	Day	5% 3 10% 4 3 3 3 5% 7% 57%	2832
	21st to end	Day	1 8% 4 10% 4 4 4 3 5% 8% 49%	3146
February	1st to 10th	Day	6% 4 7% 4 3 4 2 7% 6% 57%	1733
	11th to 20th	Day	1 4 2 6% 4 3 4 3 6% 8% 60%	1849
	21st to end	Day	7% 4 9% 5% 3 3 3 4 6% 54%	1570
March	1st to 10th	Day	1 8% 3 5% 4 3 3 3 5% 6% 59%	3152
	11th to 20th	Day	2 8% 4 9% 5% 5% 5% 5% 7% 8% 43%	3490
	21st to end	Day	1 10% 4 7% 4 4 4 4 4 7% 50%	4031
April	1st to 10th	Day	2 7% 2 6% 4 4 4 4 5% 7% 53%	2280
	11th to 20th	Day	3 10% 3 7% 4 4 4 4 5% 7% 51%	2251
	21st to end	Day	4 11% 3 6% 4 4 4 4 6% 6% 48%	2280
May	1st to 10th	Day	4 9% 2 6% 4 4 3 3 5% 5% 56%	3824
	11th to 20th	Day	4 7% 2 6% 5% 5% 6% 5% 7% 7% 46%	4229
	21st to end	Day	3 3 1 4 4 3 4 4 7% 8% 59%	4825
June	1st to 10th	Day	3 4 1 4 4 4 5% 5% 8% 9% 53%	2660
	11th to 20th	Day	3 3 1 3 3 4 3 4 6% 7% 62%	2660
	21st to end	Day	4 4 2 6% 4 4 6% 6% 8% 9% 48%	2660
July	1st to 10th	Day	4 4 2 5% 4 5% 6% 5% 7% 7% 52%	4430
	11th to 20th	Day	2 3 2 5% 6% 7% 9% 7% 9% 10% 39%	4430
	21st to end	Day	4 4 2 6% 6% 6% 7% 6% 9% 8% 42%	4458
August	1st to 10th	Day	6% 5% 2 7% 6% 7% 8% 7% 10% 10% 32%	4000
	11th to 20th	Day	4 4 1 5% 4 4 5% 5% 8% 9% 52%	3726
	21st to end	Day	4 5% 2 6% 6% 6% 8% 7% 9% 11% 36%	4180
September	1st to 10th	Day	5% 4 2 6% 5% 5% 5% 5% 6% 8% 49%	2280
	11th to 20th	Day	5% 4 1 5% 4 4 4 3 6% 6% 59%	2266
	21st to end	Day	4 4 2 5% 4 3 3 3 5% 6% 62%	2090
October	1st to 10th	Day	3 4 1 3 2 2 2 2 3 5% 73%	3183
	11th to 20th	Day	3 4 1 4 3 4 5% 4 6% 7% 60%	3150
	21st to end	Day	3 4 1 3 2 2 2 2 4 5% 71%	3438
November	1st to 10th	Day	1 4 2 4 3 3 3 3 5% 8% 65%	1772
	11th to 20th	Day	1 4 1 4 3 3 3 2 5% 7% 67%	1800
	21st to end	Day	2 6% 2 5% 3 3 3 3 5% 6% 62%	1800
December	1st to 10th	Day	1 4 2 5% 2 2 2 1 4 7% 72%	2620
	11th to 20th	Day	3 1 4 3 3 2 4 5% 10% 63%	3026
	21st to end	Day	5% 2 6% 3 3 4 3 5% 8% 59%	4004
January	1st to 10th	Night	3 3 11% 5% 3 3 3 5% 6% 57%	4502
	11th to 20th	Night	1 5% 3 8% 4 3 3 2 4 7% 60%	4166
	21st to end	Night	1 7% 4 8% 5% 3 3 3 4 7% 55%	4521
February	1st to 10th	Night	1 8% 3 7% 3 2 3 3 4 7% 59%	2444
	11th to 20th	Night	1 7% 3 7% 3 3 3 3 4 7% 59%	2218
	21st to end	Night	1 9% 3 6% 4 3 3 3 4 7% 58%	1884
March	1st to 10th	Night	1 8% 3 6% 3 3 3 3 4 6% 60%	3708
	11th to 20th	Night	2 10% 3 6% 4 4 3 3 5% 8% 52%	3490
	21st to end	Night	2 10% 4 7% 3 3 3 3 4 6% 54%	3615
April	1st to 10th	Night	2 6% 2 5% 4 2 4 3 5% 8% 60%	1900
	11th to 20th	Night	2 8% 2 5% 4 4 3 3 6% 7% 56%	1877
	21st to end	Night	5% 8% 2 5% 3 4 4 3 6% 6% 54%	1900
May	1st to 10th	Night	6% 6% 1 4 3 3 3 3 4 4 62%	3143
	11th to 20th	Night	4 5% 2 6% 4 5% 6% 4 6% 7% 50%	2672
	21st to end	Night	4 4 1 3 3 3 3 3 5% 7% 64%	2762
June	1st to 10th	Night	2 2 1 4 4 4 5% 5% 7% 9% 57%	1520
	11th to 20th	Night	1 2 3 3 3 4 5% 6% 9% 65%	1520
	21st to end	Night	4 4 1 5% 5% 5% 5% 5% 8% 10% 49%	1520
July	1st to 10th	Night	3 4 2 6% 5% 6% 6% 7% 7% 7% 48%	2540
	11th to 20th	Night	2 2 1 5% 5% 5% 8% 7% 10% 11% 43%	2540
	21st to end	Night	3 4 2 5% 5% 4 5% 6% 10% 11% 44%	3100
August	1st to 10th	Night	7% 5% 3 8% 7% 7% 7% 6% 8% 9% 33%	2936
	11th to 20th	Night	3 4 1 5% 4 5% 7% 6% 11% 12% 40%	3113
	21st to end	Night	4 4 1 7% 6% 6% 8% 7% 12% 11% 34%	3487
September	1st to 10th	Night	4 4 1 5% 5% 5% 5% 5% 7% 8% 51%	1900
	11th to 20th	Night	4 3 1 3 4 3 5% 3 5% 7% 61%	1913
	21st to end	Night	4 3 1 4 2 3 4 3 4 5% 67%	2090
October	1st to 10th	Night	3 3 1 3 2 3 3 3 4 5% 70%	3784
	11th to 20th	Night	2 4 2 3 3 3 4 3 6% 7% 64%	3778
	21st to end	Night	2 3 2 3 3 2 3 2 3 5% 72%	4120
November	1st to 10th	Night	1 3 1 3 3 2 3 3 5% 7% 71%	2506
	11th to 20th	Night	1 3 1 2 2 2 2 2 5% 6% 73%	2600
	21st to end	Night	2 6% 2 4 4 3 3 4 5% 7% 60%	2600
December	1st to 10th	Night	1 4 2 4 2 2 2 2 3 6% 71%	4565
	11th to 20th	Night	1 3 1 4 3 2 3 3 5% 9% 67%	5181
	21st to end	Night	1 6% 3 8% 4 4 3 3 5% 6% 56%	6974

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	33% 4 11% 27% 20% 5%	2587
	11th to 20th	Day	30% 3 13% 33% 19% 2	2832
	21st to end	Day	35% 3 8% 27% 23% 4	3146
February	1st to 10th	Day	29% 4 13% 29% 20% 7%	1733
	11th to 20th	Day	26% 4 9% 29% 25% 7%	1859
	21st to end	Day	32% 4 5% 21% 27% 11%	1570
March	1st to 10th	Day	26% 5% 6% 25% 32% 8%	3152
	11th to 20th	Day	38% 5% 9% 28% 17% 3	3490
	21st to end	Day	35% 4 8% 33% 18% 2	4031
April	1st to 10th	Day	31% 5% 8% 25% 23% 9%	2280
	11th to 20th	Day	35% 5% 5% 26% 22% 8%	2254
	21st to end	Day	37% 5% 7% 24% 24% 4	2280
May	1st to 10th	Day	29% 5% 8% 19% 26% 14%	3824
	11th to 20th	Day	36% 5% 10% 24% 19% 7%	4233
	21st to end	Day	21% 6% 6% 19% 35% 13%	4825
June	1st to 10th	Day	25% 6% 14% 24% 21% 10%	2660
	11th to 20th	Day	21% 5% 8% 19% 26% 21%	2660
	21st to end	Day	30% 6% 9% 23% 20% 11%	2660
July	1st to 10th	Day	27% 7% 11% 16% 19% 20%	4361
	11th to 20th	Day	31% 13% 20% 25% 9% 3	4355
	21st to end	Day	33% 11% 19% 22% 12% 4	4317
August	1st to 10th	Day	41% 15% 19% 14% 7% 4	3986
	11th to 20th	Day	27% 8% 18% 20% 19% 9%	3762
	21st to end	Day	37% 11% 19% 17% 14% 2	4179
September	1st to 10th	Day	33% 6% 10% 23% 21% 8%	2280
	11th to 20th	Day	27% 4 9% 20% 29% 11%	2266
	21st to end	Day	24% 4 6% 26% 33% 7%	2090
October	1st to 10th	Day	18% 3 4 23% 38% 14%	3183
	11th to 20th	Day	22% 8% 7% 28% 28% 6%	3150
	21st to end	Day	17% 4 6% 22% 44% 7%	3438
November	1st to 10th	Day	19% 3 8% 25% 34% 10%	1772
	11th to 20th	Day	19% 4 9% 30% 31% 8%	1800
	21st to end	Day	26% 3 7% 22% 31% 12%	1800
December	1st to 10th	Day	16% 3 9% 28% 37% 8%	2620
	11th to 20th	Day	20% 4 9% 29% 34% 5%	3024
	21st to end	Day	23% 5% 9% 29% 25% 9%	4004
January	1st to 10th	Night	29% 3 11% 28% 24% 5%	4502
	11th to 20th	Night	30% 3 12% 36% 16% 4	4166
	21st to end	Night	31% 4 10% 30% 22% 4	4521
February	1st to 10th	Night	28% 3 13% 26% 23% 6%	2444
	11th to 20th	Night	28% 4 10% 30% 23% 6%	2218
	21st to end	Night	30% 3 5% 23% 32% 8%	1884
March	1st to 10th	Night	27% 5% 5% 22% 35% 6%	3708
	11th to 20th	Night	32% 3 10% 34% 18% 3	3490
	21st to end	Night	34% 4 12% 31% 18% 1	3615
April	1st to 10th	Night	24% 4 11% 29% 24% 8%	1900
	11th to 20th	Night	29% 4 8% 27% 27% 5%	1877
	21st to end	Night	33% 3 11% 30% 20% 3	1900
May	1st to 10th	Night	25% 4 6% 24% 31% 10%	3143
	11th to 20th	Night	30% 5% 14% 30% 14% 7%	2673
	21st to end	Night	20% 4 8% 25% 34% 8%	2762
June	1st to 10th	Night	22% 6% 15% 24% 20% 13%	1520
	11th to 20th	Night	16% 4 10% 25% 23% 22%	1520
	21st to end	Night	28% 7% 12% 23% 21% 10%	1520
July	1st to 10th	Night	29% 8% 14% 16% 17% 17%	2500
	11th to 20th	Night	28% 11% 24% 28% 6% 3	2492
	21st to end	Night	28% 11% 22% 23% 13% 2	3003
August	1st to 10th	Night	43% 12% 20% 13% 8% 4	2927
	11th to 20th	Night	29% 12% 21% 18% 14% 5%	3143
	21st to end	Night	36% 12% 17% 20% 12% 2	3487
September	1st to 10th	Night	29% 6% 13% 25% 21% 5%	1900
	11th to 20th	Night	22% 5% 11% 21% 29% 12%	1913
	21st to end	Night	21% 5% 8% 28% 33% 6%	2090
October	1st to 10th	Night	17% 3 8% 27% 35% 10%	3784
	11th to 20th	Night	20% 6% 8% 29% 32% 6%	3778
	21st to end	Night	16% 3 6% 29% 39% 7%	4120
November	1st to 10th	Night	16% 4 9% 29% 34% 9%	2506
	11th to 20th	Night	15% 3 7% 35% 33% 8%	2600
	21st to end	Night	25% 4 7% 23% 30% 10%	2600
December	1st to 10th	Night	18% 3 9% 32% 32% 7%	4565
	11th to 20th	Night	18% 3 9% 29% 34% 7%	5182
	21st to end	Night	28% 6% 12% 20% 28% 5%	6974

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	9% 31% 30% 22% 7% 1	288
	11th to 20th	Day	11% 32% 34% 20% 2 1	270
	21st to end	Day	5% 25% 39% 21% 9% 1	297
February	1st to 10th	Day	7% 45% 29% 16% 3	270
	11th to 20th	Day	9% 46% 29% 14% 3	270
	21st to end	Day	23% 37% 28% 9% 2	225
March	1st to 10th	Day	19% 35% 26% 15% 5%	279
	11th to 20th	Day	15% 35% 31% 14% 5% 1	460
	21st to end	Day	23% 38% 30% 8% 2	506
April	1st to 10th	Day	16% 41% 30% 11% 2	460
	11th to 20th	Day	19% 43% 27% 8% 2	452
	21st to end	Day	18% 40% 28% 11% 2	460
May	1st to 10th	Day	15% 39% 32% 10% 3	474
	11th to 20th	Day	8% 24% 35% 25% 7% 2	675
	21st to end	Day	8% 27% 31% 23% 10% 1	734
June	1st to 10th	Day	3 17% 34% 28% 16% 2	680
	11th to 20th	Day	6% 19% 35% 24% 14% 2	680
	21st to end	Day	5% 16% 31% 27% 18% 3	680
July	1st to 10th	Day	5% 8% 24% 36% 23% 3	671
	11th to 20th	Day	5% 3 18% 39% 29% 5%	668
	21st to end	Day	6% 4 22% 38% 26% 3	535
August	1st to 10th	Day	6% 7% 26% 36% 22% 2	487
	11th to 20th	Day	4 7% 30% 38% 18% 2	477
	21st to end	Day	7% 8% 30% 34% 17% 4	539
September	1st to 10th	Day	6% 11% 28% 34% 17% 4	490
	11th to 20th	Day	6% 19% 33% 28% 12% 2	476
	21st to end	Day	5% 17% 31% 27% 14% 6%	300
October	1st to 10th	Day	9% 24% 24% 23% 14% 5%	300
	11th to 20th	Day	9% 28% 31% 20% 9% 3	300
	21st to end	Day	14% 27% 27% 23% 8% 2	330
November	1st to 10th	Day	12% 32% 32% 16% 9%	300
	11th to 20th	Day	10% 27% 32% 21% 10%	300
	21st to end	Day	9% 32% 28% 24% 7%	300
December	1st to 10th	Day	15% 25% 34% 19% 7% 1	300
	11th to 20th	Day	7% 34% 37% 18% 4 1	300
	21st to end	Day	17% 32% 33% 16% 2	330
January	1st to 10th	Night	5% 22% 36% 28% 9% 1	981
	11th to 20th	Night	7% 23% 33% 26% 9% 2	790
	21st to end	Night	3 18% 37% 32% 9% 1	836
February	1st to 10th	Night	5% 25% 44% 22% 4	760
	11th to 20th	Night	4 32% 41% 17% 6%	744
	21st to end	Night	10% 28% 43% 18% 1	628
March	1st to 10th	Night	8% 30% 36% 20% 5%	760
	11th to 20th	Night	6% 24% 38% 25% 7% 1	760
	21st to end	Night	8% 30% 37% 20% 4	713
April	1st to 10th	Night	9% 34% 38% 15% 3	570
	11th to 20th	Night	11% 26% 35% 23% 5%	563
	21st to end	Night	8% 25% 40% 21% 5%	570
May	1st to 10th	Night	10% 21% 36% 25% 8% 1	570
	11th to 20th	Night	7% 18% 35% 28% 11% 1	561
	21st to end	Night	9% 21% 31% 26% 12% 1	617
June	1st to 10th	Night	2 12% 32% 35% 17% 1	570
	11th to 20th	Night	2 15% 34% 36% 12% 1	570
	21st to end	Night	3 7% 29% 36% 23% 2	570
July	1st to 10th	Night	6% 3 21% 39% 28% 2	555
	11th to 20th	Night	4 2 12% 42% 36% 5%	552
	21st to end	Night	5% 1 13% 36% 38% 6%	624
August	1st to 10th	Night	5% 4 13% 37% 36% 5%	567
	11th to 20th	Night	5% 3 16% 49% 24% 4	564
	21st to end	Night	5% 4 19% 41% 26% 4	627
September	1st to 10th	Night	4 7% 19% 43% 22% 5%	570
	11th to 20th	Night	5% 9% 27% 36% 21% 3	570
	21st to end	Night	5% 14% 24% 40% 16% 2	570
October	1st to 10th	Night	6% 17% 30% 35% 11% 1	744
	11th to 20th	Night	4 18% 34% 29% 13% 3	760
	21st to end	Night	7% 19% 31% 28% 13% 2	836
November	1st to 10th	Night	7% 21% 31% 30% 12% 1	946
	11th to 20th	Night	4 22% 38% 25% 10% 1	1000
	21st to end	Night	7% 23% 29% 30% 10% 1	1000
December	1st to 10th	Night	7% 23% 35% 27% 8%	1000
	11th to 20th	Night	6% 27% 36% 24% 8%	1000
	21st to end	Night	8% 25% 36% 27% 4 1	1100

Page generated at 2025-01-04 01:24:04. Version ac07

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