Martin Dies, Jr. State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Martin Dies, Jr. State Park clear sky chart from 2005-11-06 to 2024-11-04.

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	13% 7% 2 7% 5% 5% 5% 4 6% 7% 40%	100982
	Night	14% 7% 2 5% 4 4 4 3 5% 7% 45%	98105
Transparency	Day	41% 6% 11% 18% 17% 6%	104628
	Night	37% 6% 11% 19% 19% 9%	102599
Seeing	Day	15% 8% 21% 25% 22% 10%	14961
	Night	16% 7% 23% 32% 19% 3	24751

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	21% 8% 2 5% 3 3 4 3 5% 5% 40%	2847
	11th to 20th	Day	20% 7% 2 5% 3 2 3 2 3 5% 50%	2850
	21st to end	Day	23% 8% 2 6% 3 3 3 3 4 7% 37%	3135
February	1st to 10th	Day	20% 9% 3 7% 6% 5% 4 3 3 5% 37%	1710
	11th to 20th	Day	23% 9% 3 5% 4 3 2 3 3 4 40%	1892
	21st to end	Day	20% 9% 3 7% 4 4 3 3 4 6% 37%	1727
March	1st to 10th	Day	20% 12% 4 9% 5% 4 4 3 4 6% 29%	3436
	11th to 20th	Day	19% 8% 3 8% 6% 5% 5% 4 6% 7% 31%	3480
	21st to end	Day	18% 9% 3 7% 4 4 4 3 4 5% 40%	3814
April	1st to 10th	Day	14% 7% 3 8% 6% 5% 5% 4 5% 5% 39%	2141
	11th to 20th	Day	16% 7% 3 7% 5% 5% 5% 4 6% 6% 37%	2254
	21st to end	Day	11% 6% 3 6% 5% 5% 4 3 6% 7% 43%	2280
May	1st to 10th	Day	19% 8% 3 8% 6% 5% 5% 4 5% 7% 29%	3765
	11th to 20th	Day	14% 6% 2 7% 5% 4 4 3 6% 6% 43%	4003
	21st to end	Day	10% 6% 2 7% 6% 6% 6% 5% 8% 10% 33%	4477
June	1st to 10th	Day	8% 5% 2 7% 6% 6% 6% 6% 8% 10% 36%	2470
	11th to 20th	Day	6% 4 2 6% 6% 7% 7% 5% 8% 11% 38%	2470
	21st to end	Day	8% 6% 3 6% 6% 7% 7% 6% 9% 11% 31%	2470
July	1st to 10th	Day	8% 6% 2 8% 7% 7% 7% 5% 9% 11% 31%	4120
	11th to 20th	Day	7% 7% 3 9% 7% 7% 7% 6% 8% 10% 28%	4120
	21st to end	Day	17% 9% 3 8% 6% 5% 6% 5% 6% 8% 27%	4465
August	1st to 10th	Day	2 2 1 3 3 4 4 4 6% 8% 61%	4104
	11th to 20th	Day	3 2 1 4 3 5% 6% 5% 8% 12% 52%	3764
	21st to end	Day	9% 4 2 7% 6% 6% 7% 5% 7% 9% 39%	4180
September	1st to 10th	Day	9% 6% 3 7% 5% 6% 6% 5% 6% 8% 40%	2239
	11th to 20th	Day	14% 6% 2 7% 6% 5% 5% 4 6% 7% 39%	2090
	21st to end	Day	9% 3 2 5% 4 5% 4 4 5% 7% 50%	2082
October	1st to 10th	Day	8% 3 2 5% 4 3 4 2 4 6% 58%	1900
	11th to 20th	Day	11% 4 2 4 4 3 3 3 4 7% 54%	1900
	21st to end	Day	15% 5% 2 5% 3 3 4 2 4 5% 53%	2090
November	1st to 10th	Day	11% 6% 2 6% 5% 3 4 3 5% 7% 49%	1888
	11th to 20th	Day	11% 7% 2 7% 4 3 4 3 4 5% 50%	1900
	21st to end	Day	17% 7% 3 7% 4 3 4 3 4 4 44%	1900
December	1st to 10th	Day	17% 9% 3 6% 4 4 4 3 5% 5% 42%	1723
	11th to 20th	Day	16% 10% 3 7% 5% 4 4 4 4 4 40%	2161
	21st to end	Day	17% 8% 3 5% 5% 4 3 3 5% 6% 42%	3135
January	1st to 10th	Night	17% 8% 2 5% 3 3 3 3 4 6% 47%	4108
	11th to 20th	Night	20% 8% 2 5% 2 2 2 2 3 4 50%	4120
	21st to end	Night	25% 11% 2 5% 3 2 3 2 3 6% 37%	4532
February	1st to 10th	Night	18% 9% 3 5% 4 4 3 3 5% 6% 40%	2470
	11th to 20th	Night	22% 9% 3 4 3 3 2 2 4 5% 42%	2187
	21st to end	Night	20% 9% 3 6% 4 4 3 3 4 4 40%	1727
March	1st to 10th	Night	24% 12% 3 7% 4 4 4 3 4 5% 31%	3419
	11th to 20th	Night	22% 8% 4 7% 4 4 4 3 5% 6% 33%	3480
	21st to end	Night	14% 7% 3 6% 5% 4 4 4 4 6% 43%	3817
April	1st to 10th	Night	14% 6% 2 6% 4 5% 5% 3 5% 8% 42%	2038
	11th to 20th	Night	16% 6% 2 5% 4 3 4 3 6% 6% 44%	1875
	21st to end	Night	14% 5% 2 6% 4 4 3 3 5% 7% 47%	1900
May	1st to 10th	Night	22% 10% 3 7% 4 4 4 3 5% 8% 30%	3130
	11th to 20th	Night	16% 6% 3 7% 4 4 4 3 5% 6% 43%	2895
	21st to end	Night	11% 6% 2 6% 4 5% 5% 4 8% 10% 37%	3090
June	1st to 10th	Night	5% 5% 2 5% 4 4 4 5% 6% 10% 50%	1710
	11th to 20th	Night	4 3 1 3 3 3 5% 3 7% 10% 57%	1710
	21st to end	Night	7% 5% 2 5% 4 4 5% 4 8% 10% 45%	1710
July	1st to 10th	Night	7% 6% 2 6% 5% 5% 5% 5% 8% 12% 40%	2850
	11th to 20th	Night	6% 4 2 6% 5% 4 6% 5% 9% 11% 41%	2850
	21st to end	Night	13% 7% 3 7% 5% 4 4 4 6% 10% 35%	3098
August	1st to 10th	Night	2 2 1 2 2 2 3 2 5% 9% 70%	2836
	11th to 20th	Night	2 2 1 3 2 3 3 4 8% 12% 60%	3063
	21st to end	Night	8% 4 2 5% 5% 5% 5% 4 9% 11% 42%	3476
September	1st to 10th	Night	7% 4 2 6% 4 4 5% 4 7% 10% 47%	1935
	11th to 20th	Night	12% 6% 3 6% 4 5% 4 3 7% 7% 45%	2090
	21st to end	Night	9% 5% 2 4 3 3 3 3 5% 6% 55%	2090
October	1st to 10th	Night	5% 3 2 4 4 3 4 4 4 6% 62%	2266
	11th to 20th	Night	10% 4 2 4 3 3 3 3 5% 6% 58%	2280
	21st to end	Night	12% 5% 1 4 3 3 3 2 4 4 58%	2508
November	1st to 10th	Night	11% 6% 2 5% 3 4 3 3 4 6% 53%	2263
	11th to 20th	Night	11% 6% 1 5% 4 4 3 3 5% 6% 52%	2280
	21st to end	Night	16% 8% 2 6% 4 3 3 3 5% 6% 46%	2280
December	1st to 10th	Night	21% 9% 2 5% 3 3 3 3 5% 5% 42%	2454
	11th to 20th	Night	17% 9% 2 6% 4 4 4 3 4 5% 44%	3036
	21st to end	Night	18% 8% 2 5% 3 3 4 3 4 6% 44%	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	45% 4 5% 17% 22% 8%	2848
	11th to 20th	Day	40% 3 5% 17% 30% 6%	2850
	21st to end	Day	48% 3 4 16% 18% 10%	3135
February	1st to 10th	Day	51% 4 5% 12% 18% 10%	1710
	11th to 20th	Day	49% 3 5% 15% 17% 10%	1902
	21st to end	Day	49% 4 7% 13% 16% 10%	1727
March	1st to 10th	Day	56% 5% 8% 12% 15% 5%	3436
	11th to 20th	Day	51% 6% 7% 17% 14% 5%	3480
	21st to end	Day	47% 5% 7% 15% 22% 4	3814
April	1st to 10th	Day	47% 5% 7% 15% 18% 8%	2141
	11th to 20th	Day	46% 5% 9% 14% 16% 10%	2254
	21st to end	Day	40% 7% 8% 18% 23% 5%	2280
May	1st to 10th	Day	52% 7% 10% 17% 10% 4	3800
	11th to 20th	Day	40% 6% 9% 18% 24% 2	4007
	21st to end	Day	42% 10% 12% 25% 10% 1	4489
June	1st to 10th	Day	40% 9% 14% 20% 15% 1	2470
	11th to 20th	Day	37% 9% 15% 23% 14% 2	2470
	21st to end	Day	43% 9% 17% 20% 10% 1	2470
July	1st to 10th	Day	44% 8% 25% 19% 4	4056
	11th to 20th	Day	48% 7% 18% 20% 7%	4051
	21st to end	Day	53% 8% 15% 18% 5% 1	4325
August	1st to 10th	Day	20% 6% 15% 34% 25% 1	4090
	11th to 20th	Day	24% 8% 26% 35% 7% 1	3800
	21st to end	Day	41% 8% 16% 18% 16% 1	4179
September	1st to 10th	Day	39% 8% 14% 17% 15% 6%	2239
	11th to 20th	Day	44% 8% 12% 16% 14% 6%	2090
	21st to end	Day	33% 6% 10% 21% 18% 11%	2082
October	1st to 10th	Day	19% 3 6% 14% 21% 37%	3160
	11th to 20th	Day	21% 3 4 20% 32% 21%	3140
	21st to end	Day	28% 3 4 11% 42% 13%	3428
November	1st to 10th	Day	35% 6% 9% 18% 21% 11%	1888
	11th to 20th	Day	38% 4 6% 16% 25% 12%	1900
	21st to end	Day	44% 4 5% 18% 20% 9%	1900
December	1st to 10th	Day	45% 5% 8% 17% 17% 8%	1723
	11th to 20th	Day	48% 3 6% 14% 20% 9%	2159
	21st to end	Day	43% 4 7% 14% 25% 8%	3135
January	1st to 10th	Night	39% 3 6% 19% 24% 8%	4108
	11th to 20th	Night	41% 2 5% 17% 28% 8%	4120
	21st to end	Night	50% 3 4 17% 16% 10%	4532
February	1st to 10th	Night	46% 3 7% 15% 17% 12%	2470
	11th to 20th	Night	47% 3 6% 15% 20% 10%	2187
	21st to end	Night	48% 5% 6% 12% 16% 13%	1727
March	1st to 10th	Night	55% 4 7% 13% 14% 6%	3419
	11th to 20th	Night	52% 6% 9% 14% 14% 5%	3480
	21st to end	Night	42% 6% 9% 14% 24% 6%	3817
April	1st to 10th	Night	41% 7% 8% 18% 16% 10%	2038
	11th to 20th	Night	39% 6% 10% 18% 15% 12%	1875
	21st to end	Night	37% 6% 9% 19% 24% 6%	1900
May	1st to 10th	Night	51% 8% 10% 16% 11% 4	3160
	11th to 20th	Night	41% 6% 10% 18% 23% 3	2896
	21st to end	Night	38% 10% 17% 24% 10% 1	3099
June	1st to 10th	Night	28% 10% 17% 28% 16% 1	1710
	11th to 20th	Night	22% 8% 17% 34% 16% 3	1710
	21st to end	Night	30% 9% 22% 26% 12% 1	1710
July	1st to 10th	Night	35% 9% 33% 19% 4	2805
	11th to 20th	Night	33% 10% 27% 23% 7%	2796
	21st to end	Night	44% 9% 22% 19% 5%	2999
August	1st to 10th	Night	13% 6% 18% 35% 28% 1	2826
	11th to 20th	Night	16% 7% 31% 38% 8% 1	3093
	21st to end	Night	34% 12% 18% 19% 15% 2	3476
September	1st to 10th	Night	31% 9% 19% 19% 15% 7%	1935
	11th to 20th	Night	38% 6% 14% 19% 16% 7%	2090
	21st to end	Night	29% 5% 12% 22% 19% 13%	2090
October	1st to 10th	Night	16% 4 6% 17% 18% 39%	3786
	11th to 20th	Night	17% 2 5% 21% 31% 24%	3779
	21st to end	Night	25% 3 4 13% 38% 18%	4120
November	1st to 10th	Night	32% 4 11% 18% 23% 11%	2263
	11th to 20th	Night	33% 4 9% 18% 25% 11%	2280
	21st to end	Night	40% 4 8% 16% 21% 10%	2280
December	1st to 10th	Night	45% 5% 7% 18% 16% 9%	2454
	11th to 20th	Night	44% 4 5% 12% 22% 14%	3037
	21st to end	Night	42% 5% 7% 14% 26% 7%	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	24% 19% 38% 13% 5% 1	270
	11th to 20th	Day	27% 15% 31% 21% 5% 1	270
	21st to end	Day	27% 21% 32% 17% 3	297
February	1st to 10th	Day	26% 19% 35% 16% 3 1	270
	11th to 20th	Day	35% 15% 32% 16% 2	270
	21st to end	Day	28% 29% 33% 9% 1	225
March	1st to 10th	Day	28% 19% 31% 17% 6%	270
	11th to 20th	Day	21% 24% 36% 15% 4 1	270
	21st to end	Day	24% 14% 42% 16% 3 1	297
April	1st to 10th	Day	15% 18% 42% 19% 4 1	321
	11th to 20th	Day	25% 17% 25% 23% 9% 1	452
	21st to end	Day	17% 13% 32% 26% 10% 2	460
May	1st to 10th	Day	19% 11% 33% 25% 11% 1	463
	11th to 20th	Day	13% 7% 25% 34% 18% 3	622
	21st to end	Day	9% 6% 28% 32% 19% 5%	734
June	1st to 10th	Day	10% 3 16% 31% 28% 11%	680
	11th to 20th	Day	6% 2 17% 38% 28% 8%	680
	21st to end	Day	10% 2 13% 26% 33% 16%	680
July	1st to 10th	Day	7% 2 8% 28% 37% 17%	671
	11th to 20th	Day	7% 1 6% 25% 42% 18%	668
	21st to end	Day	9% 6% 27% 39% 19%	739
August	1st to 10th	Day	5% 1 5% 23% 43% 23%	676
	11th to 20th	Day	6% 2 1 16% 48% 28%	502
	21st to end	Day	12% 2 7% 18% 35% 26%	539
September	1st to 10th	Day	8% 2 8% 23% 38% 21%	449
	11th to 20th	Day	9% 2 12% 31% 29% 15%	300
	21st to end	Day	13% 2 11% 30% 29% 13%	300
October	1st to 10th	Day	7% 2 21% 37% 26% 7%	300
	11th to 20th	Day	9% 6% 22% 37% 18% 7%	300
	21st to end	Day	23% 8% 25% 23% 15% 6%	330
November	1st to 10th	Day	13% 7% 29% 28% 19% 3	279
	11th to 20th	Day	16% 13% 33% 30% 8% 1	270
	21st to end	Day	25% 14% 32% 20% 6% 3	270
December	1st to 10th	Day	20% 11% 34% 24% 6% 4	270
	11th to 20th	Day	25% 12% 35% 22% 5%	270
	21st to end	Day	27% 16% 34% 18% 4 2	297
January	1st to 10th	Night	23% 13% 30% 28% 6%	950
	11th to 20th	Night	26% 12% 28% 27% 7%	950
	21st to end	Night	24% 12% 31% 29% 4	1045
February	1st to 10th	Night	25% 13% 32% 26% 4	950
	11th to 20th	Night	29% 13% 32% 23% 4	712
	21st to end	Night	27% 18% 31% 23% 1	471
March	1st to 10th	Night	27% 10% 31% 26% 5%	570
	11th to 20th	Night	21% 12% 34% 28% 5% 1	570
	21st to end	Night	18% 10% 38% 26% 9%	627
April	1st to 10th	Night	18% 9% 40% 27% 6%	570
	11th to 20th	Night	20% 10% 32% 28% 10%	563
	21st to end	Night	16% 7% 37% 29% 10% 1	570
May	1st to 10th	Night	18% 8% 32% 32% 10% 1	570
	11th to 20th	Night	15% 4 27% 39% 15% 1	561
	21st to end	Night	8% 5% 26% 36% 22% 3	617
June	1st to 10th	Night	6% 2 13% 39% 35% 5%	570
	11th to 20th	Night	4 1 18% 45% 27% 5%	570
	21st to end	Night	9% 1 10% 34% 38% 7%	570
July	1st to 10th	Night	5% 1 6% 39% 38% 11%	555
	11th to 20th	Night	5% 2 6% 37% 42% 8%	552
	21st to end	Night	5% 1 7% 35% 46% 6%	624
August	1st to 10th	Night	3 1 5% 38% 46% 7%	567
	11th to 20th	Night	4 1 4 37% 45% 10%	564
	21st to end	Night	10% 1 5% 29% 44% 11%	627
September	1st to 10th	Night	8% 1 6% 31% 43% 11%	570
	11th to 20th	Night	14% 1 9% 29% 41% 7%	570
	21st to end	Night	11% 3 11% 33% 34% 8%	570
October	1st to 10th	Night	6% 2 12% 38% 37% 5%	746
	11th to 20th	Night	12% 4 21% 41% 20% 2	760
	21st to end	Night	14% 7% 25% 32% 20% 2	836
November	1st to 10th	Night	13% 5% 24% 35% 21% 2	755
	11th to 20th	Night	14% 9% 24% 38% 13%	760
	21st to end	Night	19% 10% 30% 29% 12% 1	760
December	1st to 10th	Night	26% 9% 25% 29% 11% 1	934
	11th to 20th	Night	25% 9% 30% 29% 6%	950
	21st to end	Night	24% 10% 31% 28% 6%	1045

Page generated at 2024-11-01 21:47:39. Version ac07

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