Mustang Island State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mustang Island State Park clear sky chart from 2005-11-06 to 2024-11-02.

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	12% 6% 2 5% 4 4 4 4 6% 9% 44%	100895
	Night	13% 6% 2 5% 4 4 4 4 6% 8% 46%	98175
Transparency	Day	35% 9% 18% 22% 12% 4	100706
	Night	35% 8% 16% 21% 14% 6%	98035
Seeing	Day	11% 3 11% 25% 35% 15%	14517
	Night	14% 4 13% 30% 32% 8%	24436

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	18% 7% 3 7% 3 4 4 4 6% 7% 38%	2847
	11th to 20th	Day	15% 8% 2 5% 4 4 3 3 5% 7% 44%	2850
	21st to end	Day	22% 7% 2 6% 4 4 5% 4 5% 5% 36%	3373
February	1st to 10th	Day	21% 9% 2 6% 4 3 3 4 5% 5% 38%	1900
	11th to 20th	Day	19% 7% 3 6% 3 3 3 2 5% 7% 42%	1849
	21st to end	Day	18% 7% 3 5% 4 3 3 4 5% 5% 43%	1646
March	1st to 10th	Day	22% 11% 3 8% 4 4 4 4 5% 6% 30%	3436
	11th to 20th	Day	25% 9% 4 8% 5% 4 4 3 5% 6% 28%	3480
	21st to end	Day	11% 4 2 6% 3 4 4 3 5% 6% 51%	3814
April	1st to 10th	Day	14% 7% 2 5% 4 5% 5% 4 6% 8% 41%	2090
	11th to 20th	Day	15% 7% 3 6% 5% 4 3 3 5% 7% 42%	2066
	21st to end	Day	12% 6% 2 5% 5% 4 4 4 6% 7% 46%	2256
May	1st to 10th	Day	16% 8% 2 6% 5% 4 4 4 7% 10% 34%	4034
	11th to 20th	Day	12% 6% 2 7% 5% 5% 5% 4 7% 8% 40%	4082
	21st to end	Day	7% 4 1 4 4 5% 5% 4 7% 10% 47%	4477
June	1st to 10th	Day	4 2 1 4 3 3 4 4 8% 12% 55%	2470
	11th to 20th	Day	3 3 1 3 4 4 4 4 8% 12% 54%	2470
	21st to end	Day	5% 4 1 4 5% 4 5% 5% 9% 14% 44%	2470
July	1st to 10th	Day	6% 4 2 6% 4 4 4 5% 7% 11% 47%	4120
	11th to 20th	Day	5% 5% 3 8% 6% 6% 7% 6% 8% 12% 34%	4120
	21st to end	Day	9% 6% 2 6% 4 5% 5% 4 7% 11% 42%	4465
August	1st to 10th	Day	1 1 2 2 2 2 3 5% 8% 74%	4104
	11th to 20th	Day	2 2 1 3 3 3 5% 5% 9% 15% 52%	3713
	21st to end	Day	4 2 1 4 4 5% 7% 5% 8% 14% 44%	3828
September	1st to 10th	Day	9% 6% 2 7% 5% 5% 6% 4 8% 10% 37%	2090
	11th to 20th	Day	10% 6% 2 6% 5% 5% 6% 4 6% 8% 42%	2090
	21st to end	Day	9% 4 2 5% 4 4 4 4 7% 10% 47%	2090
October	1st to 10th	Day	5% 4 1 5% 5% 4 4 4 5% 9% 54%	2090
	11th to 20th	Day	10% 5% 2 5% 4 4 4 4 4 7% 53%	1926
	21st to end	Day	10% 4 2 4 4 4 3 2 5% 7% 56%	2090
November	1st to 10th	Day	11% 5% 2 4 3 4 5% 4 6% 8% 47%	1868
	11th to 20th	Day	16% 7% 3 5% 4 3 4 3 5% 6% 46%	1900
	21st to end	Day	17% 6% 2 5% 4 4 4 3 4 6% 43%	1785
December	1st to 10th	Day	21% 7% 2 6% 3 3 4 4 5% 7% 39%	1710
	11th to 20th	Day	16% 8% 2 7% 4 5% 4 3 5% 6% 40%	2161
	21st to end	Day	17% 7% 2 6% 3 3 4 3 5% 7% 41%	3135
January	1st to 10th	Night	21% 7% 2 6% 3 4 4 3 4 6% 40%	4108
	11th to 20th	Night	16% 6% 2 5% 3 3 3 3 5% 6% 48%	4120
	21st to end	Night	23% 7% 3 7% 4 4 3 3 6% 6% 34%	4309
February	1st to 10th	Night	19% 7% 3 5% 4 4 4 3 5% 6% 41%	2280
	11th to 20th	Night	19% 6% 2 4 3 3 4 4 5% 6% 44%	2218
	21st to end	Night	18% 9% 2 5% 4 4 3 4 3 7% 42%	1806
March	1st to 10th	Night	21% 10% 3 6% 3 3 3 4 5% 8% 34%	3419
	11th to 20th	Night	20% 11% 4 9% 5% 5% 5% 3 5% 6% 27%	3480
	21st to end	Night	12% 6% 2 4 2 3 2 2 5% 6% 56%	3817
April	1st to 10th	Night	14% 8% 2 6% 4 4 4 4 6% 8% 39%	2090
	11th to 20th	Night	16% 7% 2 5% 4 5% 4 2 5% 8% 41%	2063
	21st to end	Night	13% 8% 2 6% 5% 3 4 4 6% 8% 40%	1923
May	1st to 10th	Night	22% 6% 1 4 3 3 4 4 6% 8% 38%	2864
	11th to 20th	Night	14% 7% 2 6% 4 5% 4 5% 6% 8% 39%	2823
	21st to end	Night	9% 5% 2 6% 4 5% 5% 4 7% 10% 43%	3090
June	1st to 10th	Night	4 2 1 3 3 3 5% 4 9% 10% 54%	1710
	11th to 20th	Night	4 3 1 5% 3 4 5% 4 8% 14% 49%	1710
	21st to end	Night	6% 4 1 5% 4 4 5% 6% 7% 12% 46%	1710
July	1st to 10th	Night	5% 4 2 4 4 4 4 4 7% 10% 53%	2850
	11th to 20th	Night	3 4 2 6% 5% 6% 7% 5% 9% 13% 40%	2850
	21st to end	Night	6% 6% 2 5% 4 4 5% 4 7% 12% 45%	3098
August	1st to 10th	Night	1 1 1 2 2 2 4 9% 78%	2836
	11th to 20th	Night	2 2 1 3 3 3 4 4 8% 14% 55%	3120
	21st to end	Night	2 2 1 3 3 3 4 4 7% 13% 58%	3828
September	1st to 10th	Night	7% 5% 2 5% 4 5% 6% 5% 7% 10% 43%	2090
	11th to 20th	Night	9% 7% 2 5% 5% 4 4 4 5% 9% 43%	2090
	21st to end	Night	8% 3 2 5% 4 4 4 4 6% 9% 51%	2090
October	1st to 10th	Night	4 3 2 4 3 4 4 4 6% 8% 57%	2090
	11th to 20th	Night	9% 4 1 4 3 3 3 2 5% 7% 58%	2232
	21st to end	Night	10% 4 1 4 3 3 3 3 5% 6% 60%	2508
November	1st to 10th	Night	11% 4 1 4 3 3 3 4 5% 8% 54%	2244
	11th to 20th	Night	16% 6% 2 5% 4 3 3 3 4 5% 50%	2280
	21st to end	Night	17% 7% 2 6% 3 4 4 3 5% 6% 43%	2391
December	1st to 10th	Night	19% 7% 2 5% 4 3 3 3 4 7% 45%	2470
	11th to 20th	Night	18% 8% 3 5% 4 4 4 3 6% 6% 39%	3036
	21st to end	Night	15% 7% 2 6% 4 4 4 4 6% 6% 41%	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	42% 9% 10% 16% 14% 9%	2848
	11th to 20th	Day	38% 10% 10% 16% 15% 10%	2850
	21st to end	Day	49% 5% 8% 14% 17% 7%	3373
February	1st to 10th	Day	47% 7% 8% 13% 16% 9%	1900
	11th to 20th	Day	43% 5% 11% 18% 16% 7%	1859
	21st to end	Day	42% 6% 11% 20% 13% 7%	1646
March	1st to 10th	Day	53% 9% 11% 16% 8% 3	3436
	11th to 20th	Day	55% 8% 10% 13% 10% 5%	3480
	21st to end	Day	31% 7% 15% 21% 16% 10%	3814
April	1st to 10th	Day	39% 7% 16% 17% 13% 7%	2090
	11th to 20th	Day	41% 7% 14% 18% 13% 8%	2066
	21st to end	Day	34% 9% 14% 23% 12% 7%	2256
May	1st to 10th	Day	40% 13% 19% 16% 8% 4	4072
	11th to 20th	Day	36% 11% 14% 20% 14% 3	4086
	21st to end	Day	25% 11% 18% 36% 9%	4489
June	1st to 10th	Day	19% 9% 21% 35% 16%	2470
	11th to 20th	Day	20% 9% 19% 35% 15% 1	2470
	21st to end	Day	26% 12% 27% 27% 7% 1	2470
July	1st to 10th	Day	30% 9% 31% 27% 3	4056
	11th to 20th	Day	39% 13% 27% 17% 4	4051
	21st to end	Day	36% 10% 30% 22% 2	4325
August	1st to 10th	Day	10% 7% 26% 46% 11%	4090
	11th to 20th	Day	19% 10% 39% 29% 3	3749
	21st to end	Day	27% 13% 26% 27% 6% 1	3827
September	1st to 10th	Day	39% 13% 17% 20% 9% 2	2090
	11th to 20th	Day	37% 11% 16% 22% 12% 2	2090
	21st to end	Day	31% 11% 14% 25% 14% 6%	2090
October	1st to 10th	Day	27% 8% 13% 23% 23% 6%	2090
	11th to 20th	Day	31% 7% 13% 21% 19% 9%	1926
	21st to end	Day	27% 6% 10% 22% 24% 11%	2090
November	1st to 10th	Day	32% 8% 15% 22% 18% 5%	1868
	11th to 20th	Day	41% 6% 11% 17% 17% 8%	1900
	21st to end	Day	43% 7% 11% 19% 13% 7%	1785
December	1st to 10th	Day	46% 5% 12% 18% 14% 4	1710
	11th to 20th	Day	42% 8% 10% 12% 17% 11%	2159
	21st to end	Day	42% 7% 9% 20% 16% 6%	3135
January	1st to 10th	Night	44% 7% 8% 12% 14% 15%	4108
	11th to 20th	Night	36% 6% 10% 18% 20% 12%	4120
	21st to end	Night	51% 5% 7% 12% 16% 9%	4309
February	1st to 10th	Night	44% 5% 10% 13% 15% 13%	2280
	11th to 20th	Night	41% 6% 11% 14% 19% 8%	2218
	21st to end	Night	43% 6% 7% 19% 18% 8%	1806
March	1st to 10th	Night	46% 7% 14% 17% 12% 4	3419
	11th to 20th	Night	56% 8% 12% 9% 9% 6%	3480
	21st to end	Night	28% 6% 13% 20% 24% 9%	3817
April	1st to 10th	Night	42% 7% 13% 17% 14% 7%	2090
	11th to 20th	Night	42% 6% 11% 16% 15% 9%	2063
	21st to end	Night	39% 8% 12% 18% 14% 8%	1923
May	1st to 10th	Night	42% 8% 16% 20% 9% 5%	2891
	11th to 20th	Night	38% 10% 16% 20% 12% 4	2824
	21st to end	Night	31% 9% 17% 33% 9%	3099
June	1st to 10th	Night	20% 7% 20% 34% 17% 1	1710
	11th to 20th	Night	25% 8% 14% 33% 18% 1	1710
	21st to end	Night	28% 9% 25% 30% 7% 1	1710
July	1st to 10th	Night	27% 7% 29% 33% 4	2805
	11th to 20th	Night	31% 12% 33% 18% 5%	2796
	21st to end	Night	31% 9% 34% 23% 3	2999
August	1st to 10th	Night	6% 5% 25% 51% 12%	2826
	11th to 20th	Night	18% 10% 39% 31% 2	3150
	21st to end	Night	17% 11% 33% 30% 9% 1	3828
September	1st to 10th	Night	32% 13% 23% 19% 10% 3	2090
	11th to 20th	Night	37% 9% 16% 24% 12% 2	2090
	21st to end	Night	30% 8% 14% 25% 17% 6%	2090
October	1st to 10th	Night	24% 9% 13% 25% 19% 10%	2090
	11th to 20th	Night	26% 6% 12% 25% 19% 11%	2232
	21st to end	Night	27% 4 8% 22% 26% 13%	2508
November	1st to 10th	Night	30% 8% 13% 23% 21% 6%	2244
	11th to 20th	Night	39% 5% 11% 19% 18% 8%	2280
	21st to end	Night	42% 6% 10% 21% 14% 8%	2391
December	1st to 10th	Night	42% 5% 11% 22% 14% 6%	2470
	11th to 20th	Night	42% 8% 10% 14% 14% 12%	3037
	21st to end	Night	42% 8% 10% 13% 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	20% 7% 26% 30% 18% 1	270
	11th to 20th	Day	19% 6% 21% 34% 17% 3	270
	21st to end	Day	21% 8% 23% 34% 13% 1	297
February	1st to 10th	Day	23% 4 20% 36% 14% 2	270
	11th to 20th	Day	24% 7% 18% 31% 19% 1	270
	21st to end	Day	21% 4 25% 42% 7% 1	225
March	1st to 10th	Day	19% 6% 23% 37% 14%	270
	11th to 20th	Day	23% 7% 19% 39% 12%	270
	21st to end	Day	12% 6% 25% 45% 12%	297
April	1st to 10th	Day	14% 6% 26% 38% 15%	270
	11th to 20th	Day	17% 4 23% 37% 16% 3	264
	21st to end	Day	12% 5% 25% 37% 19% 1	436
May	1st to 10th	Day	10% 5% 20% 47% 17% 1	618
	11th to 20th	Day	10% 3 13% 46% 25% 2	675
	21st to end	Day	5% 3 12% 38% 40% 3	734
June	1st to 10th	Day	5% 1 5% 24% 54% 11%	680
	11th to 20th	Day	5% 1 4 25% 54% 12%	680
	21st to end	Day	7% 1 3 18% 49% 21%	680
July	1st to 10th	Day	5% 1 3 16% 45% 30%	671
	11th to 20th	Day	4 1 6% 51% 36%	668
	21st to end	Day	5% 2 6% 55% 32%	739
August	1st to 10th	Day	1 1 6% 53% 39%	676
	11th to 20th	Day	3 1 1 6% 44% 45%	477
	21st to end	Day	7% 1 2 7% 31% 52%	330
September	1st to 10th	Day	11% 2 3 11% 40% 33%	300
	11th to 20th	Day	10% 2 9% 38% 40%	300
	21st to end	Day	7% 1 3 11% 45% 32%	300
October	1st to 10th	Day	8% 1 3 16% 54% 18%	300
	11th to 20th	Day	11% 2 5% 20% 46% 16%	300
	21st to end	Day	13% 3 15% 26% 35% 8%	330
November	1st to 10th	Day	14% 4 7% 22% 46% 7%	273
	11th to 20th	Day	25% 4 9% 26% 29% 7%	270
	21st to end	Day	27% 4 19% 30% 17% 4	270
December	1st to 10th	Day	24% 3 13% 30% 24% 6%	270
	11th to 20th	Day	20% 9% 18% 33% 19% 1	270
	21st to end	Day	19% 4 21% 37% 16% 3	297
January	1st to 10th	Night	23% 6% 19% 35% 15% 2	950
	11th to 20th	Night	20% 6% 21% 37% 16% 1	950
	21st to end	Night	22% 5% 25% 33% 15% 1	913
February	1st to 10th	Night	22% 7% 21% 36% 14% 1	760
	11th to 20th	Night	22% 7% 20% 36% 14% 1	744
	21st to end	Night	23% 6% 19% 40% 11%	550
March	1st to 10th	Night	17% 5% 21% 38% 18% 1	570
	11th to 20th	Night	16% 6% 21% 41% 15% 1	570
	21st to end	Night	13% 5% 20% 47% 15% 1	627
April	1st to 10th	Night	17% 4 21% 42% 16%	570
	11th to 20th	Night	18% 6% 20% 39% 17%	563
	21st to end	Night	14% 5% 21% 41% 18% 1	570
May	1st to 10th	Night	14% 4 18% 45% 19%	570
	11th to 20th	Night	11% 2 14% 48% 23% 2	561
	21st to end	Night	6% 2 10% 41% 39% 1	617
June	1st to 10th	Night	4 1 3 30% 56% 6%	570
	11th to 20th	Night	4 1 3 33% 56% 3	570
	21st to end	Night	6% 1 5% 21% 51% 16%	570
July	1st to 10th	Night	5% 1 4 20% 51% 19%	555
	11th to 20th	Night	3 1 2 9% 59% 27%	552
	21st to end	Night	4 1 1 11% 61% 22%	624
August	1st to 10th	Night	1 7% 61% 30%	567
	11th to 20th	Night	2 1 1 7% 60% 29%	564
	21st to end	Night	5% 1 10% 49% 35%	627
September	1st to 10th	Night	7% 1 1 12% 54% 24%	570
	11th to 20th	Night	10% 1 4 14% 49% 22%	570
	21st to end	Night	9% 1 4 15% 54% 16%	570
October	1st to 10th	Night	5% 1 6% 18% 55% 15%	570
	11th to 20th	Night	10% 2 7% 28% 46% 7%	712
	21st to end	Night	11% 3 11% 34% 34% 6%	836
November	1st to 10th	Night	10% 2 10% 27% 44% 6%	748
	11th to 20th	Night	19% 3 14% 28% 33% 4	760
	21st to end	Night	18% 4 18% 32% 24% 3	871
December	1st to 10th	Night	20% 5% 18% 28% 24% 5%	950
	11th to 20th	Night	20% 6% 20% 34% 19% 2	950
	21st to end	Night	21% 7% 22% 32% 17% 2	1045

Page generated at 2024-10-30 12:19:24. Version ac07

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