Camp Tres Ritos
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camp Tres Ritos clear sky chart from 2005-11-06 to 2024-12-09.

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 5% 4 4 5% 4 6% 8% 55%	105154
	Night	2 4 2 4 3 3 4 3 6% 8% 60%	103340
Transparency	Day	25% 5% 11% 20% 25% 15%	104908
	Night	19% 4 13% 23% 26% 14%	103176
Seeing	Day	13% 22% 29% 23% 11% 2	15331
	Night	8% 19% 31% 28% 13% 2	25455

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 6% 2 4 4 3 5% 8% 61%	2643
	11th to 20th	Day	1 3 1 7% 4 3 3 3 4 7% 66%	2860
	21st to end	Day	1 8% 2 6% 3 4 4 3 7% 7% 53%	3146
February	1st to 10th	Day	4 2 7% 4 3 4 4 5% 9% 58%	1763
	11th to 20th	Day	4 2 6% 4 4 4 3 4 7% 63%	1849
	21st to end	Day	4 2 5% 3 5% 4 4 6% 7% 59%	1570
March	1st to 10th	Day	1 6% 3 4 2 3 3 2 4 8% 65%	3191
	11th to 20th	Day	2 14% 8% 7% 4 3 4 3 5% 6% 43%	3490
	21st to end	Day	1 6% 2 5% 3 4 5% 3 6% 7% 58%	4006
April	1st to 10th	Day	1 5% 1 4 4 3 3 4 6% 8% 60%	2280
	11th to 20th	Day	3 7% 2 5% 3 3 3 4 5% 7% 59%	2251
	21st to end	Day	3 6% 2 4 4 4 4 3 5% 9% 57%	2280
May	1st to 10th	Day	2 8% 2 3 3 3 3 3 5% 6% 62%	3800
	11th to 20th	Day	8% 6% 2 4 3 4 5% 4 6% 8% 49%	4039
	21st to end	Day	2 3 1 3 2 3 3 3 4 7% 70%	4825
June	1st to 10th	Day	2 4 2 5% 3 4 5% 5% 6% 9% 56%	2660
	11th to 20th	Day	2 2 1 3 3 3 4 4 5% 8% 63%	2660
	21st to end	Day	6% 4 2 5% 5% 5% 6% 5% 8% 8% 47%	2660
July	1st to 10th	Day	4 3 1 5% 5% 5% 6% 5% 8% 8% 48%	4430
	11th to 20th	Day	3 4 1 5% 5% 7% 9% 7% 11% 9% 36%	4252
	21st to end	Day	8% 6% 3 9% 7% 7% 7% 6% 9% 9% 29%	4454
August	1st to 10th	Day	6% 5% 2 7% 7% 8% 9% 7% 9% 9% 31%	3943
	11th to 20th	Day	5% 4 2 7% 5% 5% 6% 5% 7% 7% 47%	3726
	21st to end	Day	6% 5% 2 7% 6% 7% 7% 6% 8% 10% 36%	4180
September	1st to 10th	Day	8% 7% 2 7% 6% 4 6% 3 6% 7% 45%	2280
	11th to 20th	Day	7% 5% 2 5% 4 4 4 3 6% 7% 53%	2271
	21st to end	Day	5% 4 2 5% 3 3 4 3 4 6% 62%	2090
October	1st to 10th	Day	5% 4 2 4 3 3 3 3 4 5% 62%	3180
	11th to 20th	Day	5% 6% 2 6% 3 3 4 3 5% 7% 57%	3150
	21st to end	Day	2 3 1 2 1 1 2 2 3 5% 78%	3438
November	1st to 10th	Day	1 4 1 2 2 3 2 3 6% 7% 69%	1823
	11th to 20th	Day	1 4 1 3 2 2 3 3 5% 8% 69%	1800
	21st to end	Day	1 5% 2 4 4 3 3 2 5% 7% 64%	1800
December	1st to 10th	Day	1 4 2 4 1 3 3 3 5% 9% 67%	1644
	11th to 20th	Day	1 4 2 5% 4 4 4 4 6% 10% 58%	1926
	21st to end	Day	4 2 5% 3 3 3 3 5% 7% 65%	2794
January	1st to 10th	Night	2 2 7% 3 5% 5% 3 5% 7% 61%	4339
	11th to 20th	Night	1 2 1 4 3 3 4 4 6% 7% 65%	4110
	21st to end	Night	4 2 5% 4 4 4 3 6% 10% 58%	4521
February	1st to 10th	Night	3 2 5% 4 3 4 3 5% 9% 62%	2414
	11th to 20th	Night	1 4 3 5% 3 2 4 4 5% 8% 62%	2218
	21st to end	Night	1 3 1 6% 2 3 3 3 5% 7% 66%	1884
March	1st to 10th	Night	4 1 3 2 3 3 2 4 8% 69%	3659
	11th to 20th	Night	1 11% 6% 7% 3 3 2 3 4 5% 55%	3490
	21st to end	Night	1 3 2 5% 3 4 4 3 5% 7% 62%	3640
April	1st to 10th	Night	1 3 2 3 3 3 3 3 5% 7% 67%	1900
	11th to 20th	Night	1 6% 2 4 3 3 3 3 5% 7% 63%	1877
	21st to end	Night	3 5% 1 4 3 3 3 3 4 8% 64%	1900
May	1st to 10th	Night	2 7% 1 2 2 2 3 2 4 5% 69%	3170
	11th to 20th	Night	5% 9% 1 4 3 3 3 3 6% 9% 52%	2845
	21st to end	Night	3 2 1 3 2 2 3 2 4 6% 71%	2762
June	1st to 10th	Night	2 4 1 4 4 5% 5% 5% 7% 10% 54%	1520
	11th to 20th	Night	1 2 1 2 3 3 4 4 7% 6% 67%	1520
	21st to end	Night	7% 4 1 4 3 5% 5% 5% 7% 9% 50%	1520
July	1st to 10th	Night	3 4 2 8% 6% 6% 6% 5% 8% 8% 42%	2540
	11th to 20th	Night	3 3 1 5% 5% 4 7% 6% 11% 14% 41%	2714
	21st to end	Night	7% 6% 2 5% 4 5% 4 5% 7% 11% 44%	3109
August	1st to 10th	Night	5% 4 1 6% 5% 6% 8% 7% 12% 15% 31%	2994
	11th to 20th	Night	4 2 1 4 4 5% 6% 5% 9% 14% 45%	3113
	21st to end	Night	3 3 2 5% 4 5% 7% 7% 13% 14% 37%	3487
September	1st to 10th	Night	5% 4 2 4 4 3 6% 4 6% 9% 54%	1900
	11th to 20th	Night	4 4 1 4 2 3 4 3 7% 7% 60%	1908
	21st to end	Night	4 3 1 3 3 2 3 3 5% 7% 65%	2090
October	1st to 10th	Night	3 2 1 2 2 2 2 2 3 4 75%	3786
	11th to 20th	Night	4 6% 2 3 2 2 2 2 4 6% 68%	3778
	21st to end	Night	2 3 1 2 2 2 2 2 4 6% 76%	4120
November	1st to 10th	Night	1 2 1 2 2 2 2 2 4 6% 75%	2454
	11th to 20th	Night	2 1 2 1 2 2 2 5% 8% 74%	2600
	21st to end	Night	1 4 2 4 3 3 3 3 6% 7% 64%	2600
December	1st to 10th	Night	1 3 2 3 3 3 2 3 4 8% 70%	2714
	11th to 20th	Night	1 3 2 5% 3 5% 4 3 6% 10% 57%	3271
	21st to end	Night	1 3 1 4 3 3 4 3 5% 8% 65%	4873

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	16% 3 11% 26% 33% 11%	2644
	11th to 20th	Day	13% 2 12% 35% 30% 7%	2860
	21st to end	Day	25% 4 12% 24% 26% 10%	3146
February	1st to 10th	Day	22% 4 13% 23% 24% 15%	1763
	11th to 20th	Day	20% 4 9% 27% 26% 16%	1859
	21st to end	Day	20% 2 9% 18% 32% 20%	1570
March	1st to 10th	Day	17% 3 5% 17% 35% 22%	3191
	11th to 20th	Day	36% 4 8% 20% 26% 6%	3490
	21st to end	Day	21% 4 9% 26% 34% 8%	4006
April	1st to 10th	Day	19% 3 10% 25% 26% 16%	2280
	11th to 20th	Day	23% 3 7% 23% 29% 16%	2254
	21st to end	Day	22% 4 9% 24% 30% 10%	2280
May	1st to 10th	Day	22% 3 9% 17% 28% 22%	3800
	11th to 20th	Day	30% 6% 10% 16% 25% 12%	4043
	21st to end	Day	15% 4 7% 13% 28% 33%	4825
June	1st to 10th	Day	23% 6% 13% 21% 23% 14%	2660
	11th to 20th	Day	18% 6% 7% 16% 24% 29%	2660
	21st to end	Day	31% 7% 11% 17% 18% 16%	2660
July	1st to 10th	Day	28% 10% 12% 12% 17% 21%	4361
	11th to 20th	Day	33% 12% 16% 27% 8% 3	4178
	21st to end	Day	43% 10% 16% 20% 7% 4	4314
August	1st to 10th	Day	41% 11% 19% 16% 9% 4	3929
	11th to 20th	Day	31% 8% 14% 21% 16% 10%	3762
	21st to end	Day	37% 8% 18% 22% 13% 2	4179
September	1st to 10th	Day	35% 8% 12% 19% 19% 8%	2280
	11th to 20th	Day	28% 6% 10% 18% 23% 14%	2271
	21st to end	Day	22% 5% 7% 21% 32% 13%	2090
October	1st to 10th	Day	20% 5% 6% 15% 32% 22%	3180
	11th to 20th	Day	26% 3 7% 17% 31% 17%	3150
	21st to end	Day	12% 1 4 15% 40% 28%	3438
November	1st to 10th	Day	13% 2 9% 20% 36% 20%	1823
	11th to 20th	Day	12% 3 8% 27% 34% 16%	1800
	21st to end	Day	18% 3 7% 21% 29% 23%	1800
December	1st to 10th	Day	15% 3 15% 27% 27% 14%	1644
	11th to 20th	Day	19% 3 13% 22% 27% 15%	1924
	21st to end	Day	17% 2 9% 19% 32% 20%	2794
January	1st to 10th	Night	20% 3 11% 24% 31% 11%	4339
	11th to 20th	Night	13% 2 18% 33% 27% 8%	4110
	21st to end	Night	20% 2 16% 25% 27% 10%	4521
February	1st to 10th	Night	18% 2 15% 25% 25% 15%	2414
	11th to 20th	Night	18% 4 11% 29% 25% 14%	2218
	21st to end	Night	16% 1 10% 20% 34% 19%	1884
March	1st to 10th	Night	14% 2 7% 19% 37% 21%	3659
	11th to 20th	Night	29% 4 9% 26% 24% 9%	3490
	21st to end	Night	19% 3 11% 30% 33% 5%	3640
April	1st to 10th	Night	14% 3 12% 27% 30% 15%	1900
	11th to 20th	Night	20% 3 9% 24% 30% 15%	1877
	21st to end	Night	18% 4 12% 29% 29% 9%	1900
May	1st to 10th	Night	19% 3 7% 19% 32% 20%	3170
	11th to 20th	Night	27% 4 13% 24% 21% 11%	2846
	21st to end	Night	13% 4 9% 13% 27% 35%	2762
June	1st to 10th	Night	21% 7% 17% 20% 20% 15%	1520
	11th to 20th	Night	14% 4 8% 18% 26% 29%	1520
	21st to end	Night	28% 7% 13% 17% 19% 15%	1520
July	1st to 10th	Night	32% 13% 12% 12% 13% 17%	2500
	11th to 20th	Night	25% 10% 27% 28% 6% 4	2665
	21st to end	Night	32% 7% 23% 26% 10% 1	3011
August	1st to 10th	Night	33% 13% 24% 17% 8% 5%	2985
	11th to 20th	Night	25% 8% 22% 22% 16% 7%	3143
	21st to end	Night	28% 10% 28% 22% 10% 2	3487
September	1st to 10th	Night	24% 7% 17% 26% 18% 8%	1900
	11th to 20th	Night	20% 5% 14% 18% 30% 12%	1908
	21st to end	Night	18% 4 10% 25% 31% 11%	2090
October	1st to 10th	Night	14% 3 7% 19% 39% 19%	3786
	11th to 20th	Night	19% 3 7% 21% 31% 18%	3778
	21st to end	Night	12% 2 4 17% 40% 25%	4120
November	1st to 10th	Night	11% 2 7% 26% 37% 17%	2454
	11th to 20th	Night	9% 3 9% 27% 34% 18%	2600
	21st to end	Night	16% 2 10% 23% 27% 21%	2600
December	1st to 10th	Night	14% 3 14% 30% 27% 12%	2714
	11th to 20th	Night	19% 3 14% 23% 27% 15%	3272
	21st to end	Night	16% 3 13% 22% 29% 17%	4873

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	15% 37% 25% 16% 7%	270
	11th to 20th	Day	23% 32% 26% 15% 4 1	270
	21st to end	Day	9% 35% 34% 15% 6% 1	297
February	1st to 10th	Day	18% 38% 27% 14% 3	270
	11th to 20th	Day	14% 44% 24% 13% 3	270
	21st to end	Day	36% 30% 27% 5% 1	225
March	1st to 10th	Day	23% 33% 27% 15% 2	305
	11th to 20th	Day	23% 28% 32% 12% 3 1	460
	21st to end	Day	28% 38% 25% 8% 1	506
April	1st to 10th	Day	18% 40% 31% 9% 3	460
	11th to 20th	Day	24% 39% 27% 8% 1	452
	21st to end	Day	20% 38% 31% 9% 1	460
May	1st to 10th	Day	16% 36% 37% 8% 2 1	463
	11th to 20th	Day	11% 24% 34% 21% 7% 1	613
	21st to end	Day	10% 23% 34% 25% 8%	734
June	1st to 10th	Day	3 14% 33% 34% 15% 1	680
	11th to 20th	Day	6% 18% 34% 27% 14% 1	680
	21st to end	Day	7% 13% 29% 30% 18% 3	680
July	1st to 10th	Day	6% 6% 24% 36% 24% 3	671
	11th to 20th	Day	7% 2 19% 38% 27% 8%	569
	21st to end	Day	9% 4 15% 37% 28% 6%	531
August	1st to 10th	Day	9% 6% 22% 40% 17% 5%	487
	11th to 20th	Day	6% 5% 30% 36% 19% 3	477
	21st to end	Day	9% 6% 28% 34% 20% 2	539
September	1st to 10th	Day	8% 7% 27% 39% 16% 2	490
	11th to 20th	Day	10% 10% 36% 31% 12% 1	481
	21st to end	Day	7% 17% 33% 30% 11% 3	300
October	1st to 10th	Day	9% 24% 29% 23% 11% 3	300
	11th to 20th	Day	12% 25% 33% 20% 7% 3	300
	21st to end	Day	19% 23% 30% 20% 7% 1	330
November	1st to 10th	Day	17% 31% 27% 22% 3	300
	11th to 20th	Day	13% 29% 31% 19% 7%	300
	21st to end	Day	16% 33% 29% 13% 8% 1	300
December	1st to 10th	Day	17% 28% 32% 15% 7% 1	294
	11th to 20th	Day	17% 35% 27% 16% 4	270
	21st to end	Day	23% 37% 27% 10% 3	297
January	1st to 10th	Night	9% 25% 31% 23% 10% 1	898
	11th to 20th	Night	9% 26% 33% 24% 6% 2	760
	21st to end	Night	5% 27% 37% 20% 9% 2	836
February	1st to 10th	Night	8% 28% 41% 18% 5%	760
	11th to 20th	Night	7% 33% 39% 17% 5%	744
	21st to end	Night	12% 34% 41% 12% 1	628
March	1st to 10th	Night	9% 31% 35% 19% 5% 1	760
	11th to 20th	Night	10% 21% 33% 26% 9%	760
	21st to end	Night	12% 27% 40% 17% 3	725
April	1st to 10th	Night	11% 28% 41% 18% 2	570
	11th to 20th	Night	11% 29% 33% 23% 4	563
	21st to end	Night	9% 27% 37% 22% 3	570
May	1st to 10th	Night	9% 19% 40% 22% 9% 1	570
	11th to 20th	Night	8% 19% 30% 29% 13% 1	561
	21st to end	Night	7% 17% 37% 31% 8%	617
June	1st to 10th	Night	4 7% 29% 43% 17%	570
	11th to 20th	Night	2 9% 38% 40% 10% 1	570
	21st to end	Night	4 7% 27% 36% 24% 2	570
July	1st to 10th	Night	3 3 17% 43% 31% 3	555
	11th to 20th	Night	3 1 10% 41% 40% 6%	552
	21st to end	Night	5% 1 11% 32% 41% 9%	624
August	1st to 10th	Night	5% 2 10% 40% 35% 9%	567
	11th to 20th	Night	6% 2 14% 45% 29% 3	564
	21st to end	Night	3 2 15% 43% 33% 4	627
September	1st to 10th	Night	6% 2 19% 45% 26% 3	570
	11th to 20th	Night	5% 4 22% 45% 22% 2	570
	21st to end	Night	5% 10% 25% 43% 16% 1	570
October	1st to 10th	Night	5% 13% 33% 35% 12% 1	746
	11th to 20th	Night	7% 19% 31% 31% 10% 3	760
	21st to end	Night	10% 21% 28% 25% 12% 4	836
November	1st to 10th	Night	8% 20% 32% 29% 11% 1	894
	11th to 20th	Night	7% 23% 33% 26% 10% 2	1000
	21st to end	Night	10% 25% 31% 23% 11% 1	1000
December	1st to 10th	Night	12% 24% 37% 20% 7% 1	993
	11th to 20th	Night	9% 30% 32% 22% 6% 1	950
	21st to end	Night	12% 28% 36% 20% 4 1	1045

Page generated at 2024-12-06 01:54:49. Version ac07

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