Lake Casa Blanca International State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Casa Blanca International 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
Cloud Cover	Day	9% 5% 2 5% 4 4 4 3 5% 8% 51%	100911
	Night	10% 5% 2 4 3 3 3 3 5% 7% 54%	98347
Transparency	Day	30% 6% 12% 23% 19% 10%	104825
	Night	28% 6% 13% 23% 18% 12%	102560
Seeing	Day	9% 4 18% 35% 26% 8%	14477
	Night	11% 4 27% 44% 13% 1	24464

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	14% 5% 2 6% 3 3 3 2 3 6% 53%	2847
	11th to 20th	Day	12% 4 1 3 2 2 3 3 4 6% 59%	3110
	21st to end	Day	17% 6% 2 6% 4 4 4 4 6% 7% 40%	3487
February	1st to 10th	Day	13% 8% 2 7% 5% 3 3 3 3 5% 47%	1900
	11th to 20th	Day	15% 6% 2 5% 3 3 3 3 3 5% 52%	1849
	21st to end	Day	13% 6% 1 4 4 3 2 3 5% 6% 53%	1570
March	1st to 10th	Day	14% 7% 2 6% 4 4 5% 4 7% 7% 41%	3298
	11th to 20th	Day	23% 8% 3 6% 3 3 3 3 5% 6% 37%	3480
	21st to end	Day	9% 4 1 3 3 3 3 3 4 7% 60%	3814
April	1st to 10th	Day	12% 5% 1 6% 3 4 4 4 4 7% 51%	2090
	11th to 20th	Day	12% 5% 3 6% 4 3 3 4 5% 7% 48%	2145
	21st to end	Day	9% 6% 2 6% 4 4 4 4 5% 7% 49%	2280
May	1st to 10th	Day	12% 6% 2 6% 4 3 4 4 6% 8% 45%	4019
	11th to 20th	Day	10% 6% 2 6% 4 4 4 3 5% 7% 48%	4082
	21st to end	Day	5% 4 1 5% 4 4 4 3 6% 8% 55%	4477
June	1st to 10th	Day	3 2 1 4 3 4 4 3 5% 10% 59%	2470
	11th to 20th	Day	3 3 1 3 3 4 4 3 5% 9% 62%	2470
	21st to end	Day	5% 3 2 5% 5% 5% 6% 4 6% 10% 49%	2470
July	1st to 10th	Day	5% 4 2 4 5% 4 4 4 6% 9% 53%	4120
	11th to 20th	Day	5% 6% 2 7% 5% 6% 6% 5% 7% 9% 42%	4120
	21st to end	Day	4 4 2 5% 4 5% 5% 5% 8% 10% 49%	4229
August	1st to 10th	Day	1 1 1 2 2 2 2 2 3 7% 79%	3785
	11th to 20th	Day	2 1 1 3 2 3 4 4 6% 11% 62%	3726
	21st to end	Day	4 2 1 4 4 4 4 5% 6% 11% 55%	4089
September	1st to 10th	Day	9% 7% 3 8% 6% 6% 5% 4 5% 7% 41%	2090
	11th to 20th	Day	10% 5% 2 6% 5% 6% 5% 4 7% 8% 42%	2090
	21st to end	Day	7% 4 2 6% 4 5% 5% 3 6% 8% 50%	2090
October	1st to 10th	Day	6% 3 2 5% 3 4 4 3 5% 6% 58%	2090
	11th to 20th	Day	11% 5% 2 5% 3 4 4 3 5% 6% 52%	2090
	21st to end	Day	10% 3 1 3 4 3 3 2 4 5% 61%	2102
November	1st to 10th	Day	11% 6% 3 6% 4 3 4 3 5% 5% 50%	1958
	11th to 20th	Day	14% 7% 2 6% 3 3 2 3 3 6% 51%	1758
	21st to end	Day	16% 6% 2 4 4 4 3 2 5% 5% 47%	1710
December	1st to 10th	Day	17% 6% 2 4 3 4 4 2 5% 6% 46%	1710
	11th to 20th	Day	17% 7% 2 5% 4 3 4 3 5% 5% 44%	2161
	21st to end	Day	12% 6% 2 6% 4 3 3 3 5% 7% 49%	3135
January	1st to 10th	Night	15% 4 2 3 2 2 3 3 4 6% 54%	4108
	11th to 20th	Night	12% 4 1 3 2 2 2 1 4 7% 61%	3889
	21st to end	Night	20% 6% 2 6% 4 3 4 3 5% 6% 41%	4180
February	1st to 10th	Night	12% 5% 2 5% 4 3 3 3 5% 6% 52%	2280
	11th to 20th	Night	17% 5% 1 5% 3 2 2 3 4 6% 51%	2218
	21st to end	Night	11% 5% 1 4 3 3 3 3 5% 6% 55%	1884
March	1st to 10th	Night	14% 6% 2 5% 4 4 4 4 5% 6% 46%	3557
	11th to 20th	Night	22% 7% 3 7% 4 4 4 3 5% 5% 36%	3480
	21st to end	Night	11% 3 1 3 2 2 2 3 5% 6% 62%	3817
April	1st to 10th	Night	10% 4 1 4 3 4 4 3 6% 9% 51%	2090
	11th to 20th	Night	12% 5% 2 4 3 3 4 3 5% 7% 51%	1979
	21st to end	Night	13% 5% 2 5% 4 4 3 3 5% 6% 50%	1900
May	1st to 10th	Night	10% 5% 2 5% 4 3 3 4 6% 8% 51%	2869
	11th to 20th	Night	9% 5% 2 4 3 4 4 4 5% 7% 53%	2823
	21st to end	Night	6% 4 2 6% 4 4 4 3 5% 9% 54%	3090
June	1st to 10th	Night	2 2 1 3 3 2 3 4 6% 9% 66%	1710
	11th to 20th	Night	2 2 1 3 3 2 3 3 5% 9% 66%	1710
	21st to end	Night	3 3 1 4 3 5% 5% 5% 6% 11% 54%	1710
July	1st to 10th	Night	4 4 2 3 3 3 3 5% 6% 9% 58%	2850
	11th to 20th	Night	6% 5% 2 7% 4 4 5% 4 6% 9% 47%	2850
	21st to end	Night	4 4 2 5% 4 3 5% 4 6% 9% 55%	3314
August	1st to 10th	Night	1 1 1 1 1 1 1 3 5% 85%	3155
	11th to 20th	Night	1 2 1 3 3 4 5% 4 7% 12% 59%	3113
	21st to end	Night	2 2 1 4 3 3 3 3 5% 11% 61%	3574
September	1st to 10th	Night	8% 7% 2 6% 4 4 4 5% 7% 9% 45%	2090
	11th to 20th	Night	8% 5% 2 5% 4 4 4 5% 7% 10% 46%	2090
	21st to end	Night	7% 4 1 4 3 3 3 3 6% 8% 57%	2090
October	1st to 10th	Night	5% 3 2 4 3 2 4 3 4 6% 63%	2090
	11th to 20th	Night	11% 4 1 4 3 3 2 3 4 7% 58%	2090
	21st to end	Night	10% 4 1 3 2 2 3 2 2 4 68%	2475
November	1st to 10th	Night	12% 4 1 3 3 2 3 2 4 6% 58%	2340
	11th to 20th	Night	13% 5% 2 4 3 3 3 3 4 6% 55%	2424
	21st to end	Night	16% 6% 1 4 4 3 3 3 4 5% 51%	2470
December	1st to 10th	Night	17% 6% 2 4 3 2 3 3 4 6% 51%	2470
	11th to 20th	Night	17% 7% 2 4 3 2 3 3 5% 6% 49%	3036
	21st to end	Night	10% 6% 2 6% 4 3 4 4 5% 8% 49%	4532

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	34% 4 5% 10% 29% 18%	2848
	11th to 20th	Day	28% 3 6% 20% 25% 19%	3110
	21st to end	Day	42% 5% 8% 15% 22% 8%	3487
February	1st to 10th	Day	40% 5% 8% 12% 18% 17%	1900
	11th to 20th	Day	36% 4 6% 20% 18% 16%	1859
	21st to end	Day	33% 5% 9% 17% 23% 13%	1570
March	1st to 10th	Day	37% 7% 12% 19% 16% 9%	3298
	11th to 20th	Day	47% 6% 8% 11% 14% 13%	3480
	21st to end	Day	24% 5% 12% 21% 19% 20%	3814
April	1st to 10th	Day	33% 6% 11% 18% 19% 13%	2090
	11th to 20th	Day	34% 7% 10% 16% 17% 15%	2145
	21st to end	Day	33% 6% 10% 18% 18% 15%	2280
May	1st to 10th	Day	34% 8% 14% 21% 15% 8%	4056
	11th to 20th	Day	33% 8% 12% 20% 17% 10%	4086
	21st to end	Day	24% 8% 10% 40% 16% 3	4489
June	1st to 10th	Day	20% 7% 14% 29% 26% 5%	2470
	11th to 20th	Day	20% 5% 12% 27% 28% 8%	2470
	21st to end	Day	29% 9% 15% 25% 18% 3	2470
July	1st to 10th	Day	26% 7% 16% 40% 10% 1	4056
	11th to 20th	Day	36% 9% 17% 23% 13% 3	4051
	21st to end	Day	26% 9% 21% 31% 12% 1	4096
August	1st to 10th	Day	9% 4 13% 42% 31% 2	3772
	11th to 20th	Day	16% 7% 22% 42% 12% 1	3762
	21st to end	Day	22% 8% 20% 28% 19% 2	4088
September	1st to 10th	Day	41% 9% 13% 17% 14% 6%	2090
	11th to 20th	Day	38% 9% 14% 20% 16% 4	2090
	21st to end	Day	30% 8% 13% 22% 16% 12%	2090
October	1st to 10th	Day	19% 4 6% 11% 25% 35%	3480
	11th to 20th	Day	28% 6% 8% 18% 16% 24%	3458
	21st to end	Day	21% 3 7% 16% 38% 15%	3440
November	1st to 10th	Day	35% 5% 10% 18% 22% 10%	1958
	11th to 20th	Day	37% 4 8% 19% 20% 12%	1758
	21st to end	Day	39% 5% 7% 20% 15% 15%	1710
December	1st to 10th	Day	38% 6% 10% 20% 17% 10%	1710
	11th to 20th	Day	40% 7% 8% 12% 14% 19%	2159
	21st to end	Day	34% 5% 8% 20% 24% 10%	3135
January	1st to 10th	Night	30% 5% 7% 13% 23% 23%	4108
	11th to 20th	Night	25% 3 4 18% 24% 25%	3889
	21st to end	Night	43% 5% 8% 14% 20% 10%	4180
February	1st to 10th	Night	33% 6% 7% 18% 17% 20%	2280
	11th to 20th	Night	34% 5% 9% 17% 18% 16%	2218
	21st to end	Night	29% 6% 10% 19% 21% 14%	1884
March	1st to 10th	Night	36% 8% 12% 20% 13% 10%	3557
	11th to 20th	Night	49% 8% 10% 11% 13% 10%	3480
	21st to end	Night	23% 4 12% 25% 21% 15%	3817
April	1st to 10th	Night	29% 6% 14% 20% 18% 13%	2090
	11th to 20th	Night	31% 7% 14% 18% 16% 14%	1979
	21st to end	Night	33% 7% 13% 18% 17% 12%	1900
May	1st to 10th	Night	29% 9% 16% 23% 15% 9%	2896
	11th to 20th	Night	28% 8% 15% 20% 17% 10%	2824
	21st to end	Night	25% 8% 13% 39% 14% 2	3099
June	1st to 10th	Night	14% 7% 19% 32% 24% 3	1710
	11th to 20th	Night	15% 7% 13% 31% 29% 5%	1710
	21st to end	Night	24% 9% 18% 30% 16% 3	1710
July	1st to 10th	Night	21% 7% 23% 41% 7% 1	2805
	11th to 20th	Night	33% 9% 23% 22% 11% 2	2796
	21st to end	Night	24% 7% 27% 33% 9% 1	3209
August	1st to 10th	Night	6% 3 16% 47% 27% 1	3144
	11th to 20th	Night	17% 7% 31% 35% 9% 1	3143
	21st to end	Night	17% 8% 26% 34% 13% 2	3574
September	1st to 10th	Night	33% 12% 19% 18% 15% 5%	2090
	11th to 20th	Night	31% 9% 17% 25% 13% 3	2090
	21st to end	Night	24% 7% 15% 27% 16% 10%	2090
October	1st to 10th	Night	18% 5% 8% 16% 20% 33%	3480
	11th to 20th	Night	21% 4 12% 18% 21% 23%	3460
	21st to end	Night	20% 4 8% 18% 32% 19%	4075
November	1st to 10th	Night	27% 5% 9% 21% 26% 12%	2340
	11th to 20th	Night	31% 5% 11% 20% 20% 14%	2424
	21st to end	Night	36% 5% 8% 20% 18% 13%	2470
December	1st to 10th	Night	35% 5% 9% 17% 22% 11%	2470
	11th to 20th	Night	36% 6% 7% 18% 16% 18%	3037
	21st to end	Night	32% 7% 10% 15% 19% 16%	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	21% 5% 23% 36% 12% 3	270
	11th to 20th	Day	16% 7% 22% 36% 17% 2	270
	21st to end	Day	20% 7% 31% 25% 15% 2	297
February	1st to 10th	Day	16% 8% 29% 26% 20% 2	270
	11th to 20th	Day	18% 9% 32% 27% 12% 2	270
	21st to end	Day	16% 9% 30% 35% 9%	225
March	1st to 10th	Day	19% 6% 31% 30% 13% 1	270
	11th to 20th	Day	13% 7% 35% 34% 9% 1	270
	21st to end	Day	8% 9% 38% 38% 7%	297
April	1st to 10th	Day	12% 9% 36% 34% 9%	270
	11th to 20th	Day	9% 10% 33% 35% 12% 1	343
	21st to end	Day	9% 8% 39% 34% 9% 1	460
May	1st to 10th	Day	9% 6% 34% 38% 12% 1	615
	11th to 20th	Day	12% 3 31% 40% 12% 1	675
	21st to end	Day	7% 4 27% 46% 15% 1	734
June	1st to 10th	Day	3 1 11% 51% 30% 4	680
	11th to 20th	Day	3 1 11% 54% 28% 3	680
	21st to end	Day	6% 1 10% 43% 32% 9%	680
July	1st to 10th	Day	6% 2 8% 37% 36% 11%	671
	11th to 20th	Day	3 6% 36% 47% 7%	668
	21st to end	Day	3 1 4 41% 38% 12%	604
August	1st to 10th	Day	1 4 36% 46% 14%	487
	11th to 20th	Day	3 1 2 33% 44% 17%	477
	21st to end	Day	4 2 3 27% 34% 30%	487
September	1st to 10th	Day	10% 1 6% 18% 42% 22%	300
	11th to 20th	Day	5% 1 4 14% 33% 42%	300
	21st to end	Day	6% 6% 16% 45% 27%	300
October	1st to 10th	Day	9% 2 6% 20% 40% 23%	300
	11th to 20th	Day	13% 2 7% 29% 33% 16%	300
	21st to end	Day	12% 7% 17% 29% 25% 10%	330
November	1st to 10th	Day	12% 5% 14% 34% 25% 10%	300
	11th to 20th	Day	21% 4 14% 23% 31% 7%	270
	21st to end	Day	20% 8% 22% 29% 17% 5%	270
December	1st to 10th	Day	16% 4 23% 22% 27% 9%	270
	11th to 20th	Day	19% 10% 21% 26% 22% 2	270
	21st to end	Day	18% 5% 21% 32% 20% 5%	297
January	1st to 10th	Night	18% 5% 22% 42% 12% 1	950
	11th to 20th	Night	20% 4 28% 41% 8%	810
	21st to end	Night	17% 7% 27% 42% 8%	836
February	1st to 10th	Night	14% 7% 34% 39% 6% 1	760
	11th to 20th	Night	20% 6% 36% 33% 5%	744
	21st to end	Night	16% 6% 42% 33% 4	628
March	1st to 10th	Night	14% 11% 41% 31% 4	661
	11th to 20th	Night	12% 10% 44% 31% 3	570
	21st to end	Night	10% 7% 53% 28% 2	627
April	1st to 10th	Night	9% 7% 50% 33% 2	570
	11th to 20th	Night	12% 7% 49% 30% 2	563
	21st to end	Night	9% 9% 51% 27% 3	570
May	1st to 10th	Night	8% 7% 49% 32% 3	570
	11th to 20th	Night	8% 6% 46% 37% 3	561
	21st to end	Night	6% 4 47% 39% 5%	617
June	1st to 10th	Night	2 2 27% 59% 9%	570
	11th to 20th	Night	3 1 35% 54% 6% 1	570
	21st to end	Night	4 1 25% 54% 15% 1	570
July	1st to 10th	Night	7% 2 15% 60% 14% 2	555
	11th to 20th	Night	2 1 11% 71% 15%	552
	21st to end	Night	4 1 14% 66% 15%	624
August	1st to 10th	Night	2 1 11% 66% 19% 1	567
	11th to 20th	Night	3 1 12% 66% 17% 1	564
	21st to end	Night	4 1 6% 61% 26% 3	627
September	1st to 10th	Night	10% 1 9% 49% 27% 4	570
	11th to 20th	Night	9% 1 8% 43% 35% 5%	570
	21st to end	Night	8% 1 10% 45% 32% 5%	570
October	1st to 10th	Night	5% 1 12% 51% 29% 1	570
	11th to 20th	Night	11% 1 16% 49% 22% 1	570
	21st to end	Night	10% 4 22% 43% 21% 1	803
November	1st to 10th	Night	11% 4 22% 42% 21% 1	780
	11th to 20th	Night	13% 4 18% 43% 20% 2	900
	21st to end	Night	17% 5% 22% 39% 16% 1	950
December	1st to 10th	Night	18% 4 20% 42% 14% 1	950
	11th to 20th	Night	21% 5% 24% 40% 10% 1	950
	21st to end	Night	15% 4 26% 41% 13%	1045

Page generated at 2024-11-08 05:44:46. Version ac07

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