Estero Llano Grande State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Estero Llano Grande State Park clear sky chart from 2005-11-06 to 2024-11-11.

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
Transparency	Day	35% 7% 15% 23% 15% 6%	104747
	Night	34% 7% 17% 22% 14% 7%	102643
Seeing	Day	10% 5% 23% 34% 21% 7%	14292
	Night	13% 4 24% 37% 20% 2	24292

By Month

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	38% 5% 8% 19% 18% 12%	2848
	11th to 20th	Day	39% 6% 9% 19% 17% 10%	2982
	21st to end	Day	46% 6% 10% 15% 17% 7%	3487
February	1st to 10th	Day	43% 5% 9% 16% 16% 12%	1900
	11th to 20th	Day	37% 6% 10% 21% 18% 8%	1859
	21st to end	Day	36% 5% 11% 21% 19% 8%	1607
March	1st to 10th	Day	47% 6% 12% 20% 11% 5%	3436
	11th to 20th	Day	55% 5% 11% 12% 12% 5%	3480
	21st to end	Day	27% 5% 10% 25% 17% 16%	3814
April	1st to 10th	Day	37% 6% 13% 21% 14% 9%	2090
	11th to 20th	Day	39% 7% 13% 21% 15% 6%	2066
	21st to end	Day	35% 7% 12% 20% 18% 8%	2147
May	1st to 10th	Day	31% 7% 21% 26% 9% 5%	4120
	11th to 20th	Day	32% 8% 15% 24% 14% 7%	4086
	21st to end	Day	22% 6% 12% 38% 20% 2	4489
June	1st to 10th	Day	24% 7% 15% 30% 21% 3	2470
	11th to 20th	Day	27% 8% 13% 24% 24% 3	2470
	21st to end	Day	35% 10% 18% 25% 10% 1	2470
July	1st to 10th	Day	36% 9% 20% 29% 6%	4056
	11th to 20th	Day	40% 10% 26% 17% 7%	4051
	21st to end	Day	37% 8% 24% 25% 6%	4306
August	1st to 10th	Day	13% 6% 22% 47% 11%	3772
	11th to 20th	Day	22% 11% 37% 25% 5%	3762
	21st to end	Day	28% 11% 24% 27% 10% 1	3845
September	1st to 10th	Day	45% 10% 15% 17% 11% 2	2090
	11th to 20th	Day	46% 12% 14% 16% 9% 2	2090
	21st to end	Day	37% 10% 15% 22% 12% 5%	2090
October	1st to 10th	Day	28% 5% 8% 14% 27% 18%	3480
	11th to 20th	Day	27% 6% 11% 17% 27% 12%	3312
	21st to end	Day	27% 5% 10% 22% 27% 10%	3428
November	1st to 10th	Day	35% 7% 10% 22% 19% 6%	1958
	11th to 20th	Day	44% 4 9% 17% 17% 8%	1900
	21st to end	Day	40% 4 12% 19% 17% 9%	1782
December	1st to 10th	Day	43% 4 11% 21% 14% 7%	1710
	11th to 20th	Day	42% 6% 12% 13% 15% 13%	2159
	21st to end	Day	43% 5% 8% 21% 19% 5%	3135
January	1st to 10th	Night	40% 4 8% 18% 16% 14%	4108
	11th to 20th	Night	40% 6% 7% 19% 19% 11%	4017
	21st to end	Night	53% 5% 7% 13% 14% 7%	4180
February	1st to 10th	Night	42% 5% 11% 16% 14% 12%	2280
	11th to 20th	Night	41% 5% 11% 19% 17% 8%	2218
	21st to end	Night	40% 5% 9% 20% 18% 8%	1845
March	1st to 10th	Night	47% 6% 13% 20% 11% 4	3419
	11th to 20th	Night	56% 6% 14% 10% 9% 4	3480
	21st to end	Night	27% 5% 12% 24% 21% 11%	3817
April	1st to 10th	Night	39% 6% 17% 21% 12% 6%	2090
	11th to 20th	Night	43% 6% 14% 17% 13% 7%	2063
	21st to end	Night	40% 8% 14% 17% 13% 7%	2023
May	1st to 10th	Night	42% 10% 19% 17% 9% 3	2850
	11th to 20th	Night	45% 9% 16% 19% 9% 3	2824
	21st to end	Night	32% 9% 18% 32% 9%	3099
June	1st to 10th	Night	19% 7% 21% 32% 20% 2	1710
	11th to 20th	Night	23% 8% 14% 34% 18% 3	1710
	21st to end	Night	24% 11% 24% 30% 10% 1	1710
July	1st to 10th	Night	30% 9% 31% 26% 4	2805
	11th to 20th	Night	33% 10% 33% 19% 4	2796
	21st to end	Night	28% 9% 34% 25% 4	3012
August	1st to 10th	Night	7% 5% 28% 52% 8%	3144
	11th to 20th	Night	18% 8% 44% 28% 2	3143
	21st to end	Night	15% 9% 34% 32% 10% 1	3797
September	1st to 10th	Night	31% 10% 24% 24% 9% 2	2090
	11th to 20th	Night	34% 11% 20% 24% 10% 2	2090
	21st to end	Night	27% 9% 17% 27% 14% 5%	2090
October	1st to 10th	Night	18% 4 9% 20% 27% 22%	3480
	11th to 20th	Night	23% 5% 11% 20% 24% 17%	3573
	21st to end	Night	25% 4 8% 23% 31% 9%	4120
November	1st to 10th	Night	28% 7% 12% 24% 22% 7%	2340
	11th to 20th	Night	38% 6% 12% 20% 16% 8%	2287
	21st to end	Night	39% 4 13% 20% 15% 10%	2394
December	1st to 10th	Night	41% 4 11% 20% 16% 7%	2470
	11th to 20th	Night	38% 6% 10% 19% 13% 14%	3037
	21st to end	Night	43% 4 11% 14% 18% 9%	4532

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% 11% 29% 26% 10% 4	270
	11th to 20th	Day	21% 7% 32% 30% 9% 1	270
	21st to end	Day	21% 10% 36% 20% 10% 2	297
February	1st to 10th	Day	18% 11% 34% 23% 13% 1	270
	11th to 20th	Day	20% 10% 38% 24% 7%	270
	21st to end	Day	16% 11% 48% 20% 5%	225
March	1st to 10th	Day	21% 9% 34% 30% 5%	270
	11th to 20th	Day	21% 10% 37% 27% 5% 1	270
	21st to end	Day	11% 12% 48% 26% 3	297
April	1st to 10th	Day	15% 11% 40% 25% 7% 1	270
	11th to 20th	Day	12% 11% 41% 27% 8% 2	264
	21st to end	Day	11% 10% 43% 28% 7% 2	327
May	1st to 10th	Day	8% 8% 47% 26% 10% 1	653
	11th to 20th	Day	8% 7% 42% 33% 10% 1	675
	21st to end	Day	6% 3 35% 42% 12% 1	734
June	1st to 10th	Day	3 2 19% 42% 26% 8%	680
	11th to 20th	Day	5% 2 15% 51% 22% 4	680
	21st to end	Day	7% 2 13% 41% 28% 10%	680
July	1st to 10th	Day	9% 1 11% 39% 32% 8%	671
	11th to 20th	Day	5% 1 6% 40% 38% 10%	668
	21st to end	Day	6% 1 5% 42% 36% 10%	732
August	1st to 10th	Day	6% 52% 27% 14%	487
	11th to 20th	Day	2 6% 47% 33% 11%	477
	21st to end	Day	2 1 8% 23% 37% 28%	348
September	1st to 10th	Day	13% 2 5% 26% 36% 18%	300
	11th to 20th	Day	9% 4 26% 33% 29%	300
	21st to end	Day	5% 1 9% 22% 40% 23%	300
October	1st to 10th	Day	8% 1 9% 28% 36% 18%	300
	11th to 20th	Day	8% 13% 28% 35% 16%	300
	21st to end	Day	11% 5% 21% 33% 23% 8%	330
November	1st to 10th	Day	13% 3 15% 35% 30% 5%	300
	11th to 20th	Day	27% 4 14% 23% 21% 9%	270
	21st to end	Day	24% 8% 29% 19% 13% 6%	270
December	1st to 10th	Day	21% 5% 21% 28% 18% 7%	270
	11th to 20th	Day	16% 10% 26% 28% 15% 4	270
	21st to end	Day	21% 8% 26% 31% 10% 3	297
January	1st to 10th	Night	22% 6% 27% 32% 12% 1	950
	11th to 20th	Night	22% 7% 28% 35% 8%	886
	21st to end	Night	23% 6% 27% 35% 9%	836
February	1st to 10th	Night	21% 6% 34% 33% 7% 1	760
	11th to 20th	Night	21% 8% 33% 33% 5%	744
	21st to end	Night	19% 9% 41% 26% 6%	589
March	1st to 10th	Night	17% 11% 35% 32% 5%	570
	11th to 20th	Night	16% 9% 40% 31% 4	570
	21st to end	Night	13% 8% 48% 27% 4	627
April	1st to 10th	Night	14% 8% 45% 29% 5%	570
	11th to 20th	Night	16% 8% 40% 31% 6%	563
	21st to end	Night	14% 7% 44% 30% 5%	570
May	1st to 10th	Night	11% 7% 49% 28% 6%	570
	11th to 20th	Night	11% 5% 38% 40% 6%	561
	21st to end	Night	6% 4 34% 43% 12% 1	617
June	1st to 10th	Night	4 1 16% 53% 26% 1	570
	11th to 20th	Night	2 2 17% 56% 22% 1	570
	21st to end	Night	5% 2 15% 45% 31% 3	570
July	1st to 10th	Night	8% 1 8% 52% 27% 3	555
	11th to 20th	Night	4 1 7% 50% 36% 2	552
	21st to end	Night	4 1 4 52% 37% 2	624
August	1st to 10th	Night	1 5% 49% 42% 4	567
	11th to 20th	Night	2 5% 44% 44% 4	564
	21st to end	Night	5% 3 31% 53% 7%	627
September	1st to 10th	Night	7% 1 4 31% 49% 9%	570
	11th to 20th	Night	11% 1 5% 23% 51% 9%	570
	21st to end	Night	7% 1 6% 31% 45% 10%	570
October	1st to 10th	Night	4 2 6% 35% 46% 7%	570
	11th to 20th	Night	11% 2 10% 40% 34% 3	632
	21st to end	Night	8% 4 22% 42% 22% 2	836
November	1st to 10th	Night	11% 4 18% 43% 23% 2	780
	11th to 20th	Night	18% 3 19% 37% 21% 2	763
	21st to end	Night	19% 5% 25% 35% 15% 1	874
December	1st to 10th	Night	19% 4 24% 36% 15% 2	950
	11th to 20th	Night	20% 6% 26% 34% 13% 1	950
	21st to end	Night	19% 6% 28% 34% 12%	1045

Page generated at 2024-11-08 05:44:45. Version ac07

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