Lake Brownwood State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Brownwood State Park clear sky chart from 2005-11-06 to 2024-11-12.

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	8% 5% 2 4 3 3 4 3 5% 7% 56%	101093
	Night	8% 4 2 4 3 3 3 3 5% 7% 59%	98211
Transparency	Day	27% 5% 10% 22% 25% 11%	104937
	Night	25% 4 10% 22% 25% 14%	102494
Seeing	Day	9% 7% 23% 29% 24% 9%	15040
	Night	9% 6% 30% 38% 15% 1	24941

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	10% 7% 2 5% 3 2 2 2 4 5% 58%	2847
	11th to 20th	Day	8% 5% 2 4 3 2 3 3 4 6% 61%	2850
	21st to end	Day	14% 7% 2 5% 3 3 3 2 4 5% 52%	3363
February	1st to 10th	Day	11% 6% 3 5% 3 3 3 3 4 7% 52%	1900
	11th to 20th	Day	14% 7% 2 5% 3 3 2 2 4 5% 53%	1849
	21st to end	Day	14% 6% 2 5% 3 3 3 2 2 5% 56%	1570
March	1st to 10th	Day	11% 7% 2 5% 4 3 3 3 4 5% 51%	3275
	11th to 20th	Day	15% 7% 3 5% 4 4 4 3 4 7% 45%	3480
	21st to end	Day	7% 5% 2 6% 5% 4 5% 4 6% 7% 49%	3814
April	1st to 10th	Day	8% 6% 2 5% 4 4 4 4 5% 7% 53%	2090
	11th to 20th	Day	11% 5% 2 5% 4 3 3 2 5% 6% 52%	2216
	21st to end	Day	9% 6% 2 5% 4 3 3 3 5% 6% 56%	2400
May	1st to 10th	Day	12% 5% 2 7% 5% 4 4 3 5% 6% 48%	4082
	11th to 20th	Day	13% 6% 2 5% 4 3 3 2 5% 5% 51%	4082
	21st to end	Day	10% 5% 2 6% 4 4 4 4 6% 8% 46%	4477
June	1st to 10th	Day	5% 3 1 3 3 4 5% 3 6% 7% 59%	2470
	11th to 20th	Day	3 3 1 4 4 4 4 4 6% 8% 60%	2470
	21st to end	Day	5% 3 1 4 4 4 4 3 6% 8% 58%	2470
July	1st to 10th	Day	4 3 1 5% 4 4 5% 4 6% 7% 57%	4120
	11th to 20th	Day	3 2 1 3 3 3 3 4 6% 9% 64%	4120
	21st to end	Day	4 3 2 4 4 4 5% 4 5% 10% 55%	4465
August	1st to 10th	Day	1 1 2 2 3 3 3 4 7% 73%	4051
	11th to 20th	Day	5% 2 1 3 2 3 3 3 5% 9% 64%	3726
	21st to end	Day	2 2 1 5% 4 4 4 4 6% 9% 60%	4149
September	1st to 10th	Day	9% 5% 2 5% 5% 4 4 4 4 5% 54%	2090
	11th to 20th	Day	10% 5% 2 6% 3 4 5% 3 5% 7% 50%	2090
	21st to end	Day	7% 4 1 5% 3 3 3 4 4 6% 59%	2090
October	1st to 10th	Day	5% 3 1 3 3 3 3 3 5% 6% 65%	2090
	11th to 20th	Day	9% 3 1 3 2 3 2 3 3 5% 65%	1999
	21st to end	Day	11% 5% 2 3 2 2 2 2 3 4 64%	2090
November	1st to 10th	Day	11% 4 2 4 3 3 2 3 4 5% 59%	1873
	11th to 20th	Day	5% 4 2 4 3 3 4 3 5% 8% 61%	1719
	21st to end	Day	14% 6% 2 5% 4 2 3 3 4 4 55%	1710
December	1st to 10th	Day	12% 5% 2 5% 4 3 3 3 3 6% 54%	1710
	11th to 20th	Day	11% 5% 2 5% 3 3 4 4 6% 6% 51%	2161
	21st to end	Day	12% 7% 1 4 2 2 3 2 3 5% 58%	3135
January	1st to 10th	Night	12% 5% 2 3 2 2 2 2 4 6% 59%	4108
	11th to 20th	Night	10% 6% 1 3 2 2 2 1 3 4 67%	4120
	21st to end	Night	13% 7% 2 4 3 3 4 3 4 5% 52%	4331
February	1st to 10th	Night	10% 6% 2 5% 3 3 3 3 4 5% 55%	2280
	11th to 20th	Night	13% 6% 2 5% 2 3 3 3 3 6% 54%	2218
	21st to end	Night	11% 7% 2 3 4 3 3 2 4 5% 56%	1884
March	1st to 10th	Night	9% 6% 2 5% 3 3 3 4 4 5% 55%	3581
	11th to 20th	Night	14% 5% 2 5% 3 3 3 4 6% 7% 48%	3480
	21st to end	Night	7% 6% 2 5% 4 4 5% 4 6% 7% 51%	3817
April	1st to 10th	Night	6% 4 2 4 4 3 3 4 7% 8% 56%	2090
	11th to 20th	Night	10% 5% 1 5% 4 4 4 4 5% 6% 52%	1909
	21st to end	Night	7% 4 2 4 3 3 2 3 5% 6% 61%	1777
May	1st to 10th	Night	16% 7% 1 4 3 3 3 3 4 6% 48%	2823
	11th to 20th	Night	8% 6% 2 6% 3 3 3 3 4 6% 56%	2823
	21st to end	Night	9% 4 1 4 3 4 4 3 5% 9% 53%	3090
June	1st to 10th	Night	3 2 1 3 3 3 4 3 6% 9% 63%	1710
	11th to 20th	Night	3 2 1 2 3 3 3 3 6% 9% 66%	1710
	21st to end	Night	4 3 1 3 3 2 3 3 6% 8% 64%	1710
July	1st to 10th	Night	3 3 1 3 3 3 3 2 5% 8% 65%	2850
	11th to 20th	Night	2 1 1 2 2 2 2 3 4 9% 73%	2850
	21st to end	Night	2 2 1 4 4 3 4 4 6% 9% 60%	3098
August	1st to 10th	Night	1 1 1 2 2 2 2 1 5% 7% 76%	2884
	11th to 20th	Night	3 2 1 3 2 3 3 2 5% 9% 67%	3113
	21st to end	Night	2 2 2 3 3 4 4 4 6% 9% 62%	3514
September	1st to 10th	Night	6% 5% 2 4 4 4 4 3 5% 8% 56%	2090
	11th to 20th	Night	9% 5% 2 4 3 3 3 4 6% 7% 53%	2090
	21st to end	Night	7% 3 1 3 3 3 3 2 6% 8% 60%	2090
October	1st to 10th	Night	5% 3 1 3 2 2 3 2 4 7% 69%	2090
	11th to 20th	Night	9% 3 1 3 2 3 2 2 4 5% 65%	2161
	21st to end	Night	11% 4 1 3 2 2 2 2 4 5% 64%	2508
November	1st to 10th	Night	10% 4 1 4 3 3 3 3 4 4 61%	2420
	11th to 20th	Night	5% 3 1 4 2 3 4 3 4 7% 63%	2484
	21st to end	Night	14% 5% 2 5% 3 3 3 2 4 5% 54%	2470
December	1st to 10th	Night	11% 4 1 4 3 3 3 3 5% 6% 57%	2470
	11th to 20th	Night	10% 6% 2 5% 3 3 4 4 5% 6% 53%	3036
	21st to end	Night	12% 6% 2 4 3 3 3 2 4 6% 55%	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	29% 2 6% 15% 32% 15%	2848
	11th to 20th	Day	26% 2 7% 19% 31% 15%	2850
	21st to end	Day	36% 3 6% 15% 28% 12%	3363
February	1st to 10th	Day	33% 4 6% 17% 22% 18%	1900
	11th to 20th	Day	35% 3 6% 20% 21% 15%	1859
	21st to end	Day	34% 3 5% 13% 25% 20%	1570
March	1st to 10th	Day	35% 4 6% 10% 27% 18%	3275
	11th to 20th	Day	41% 5% 13% 13% 19% 9%	3480
	21st to end	Day	32% 6% 11% 16% 24% 11%	3814
April	1st to 10th	Day	31% 6% 9% 20% 18% 16%	2090
	11th to 20th	Day	33% 5% 8% 16% 23% 14%	2216
	21st to end	Day	30% 5% 8% 18% 28% 10%	2400
May	1st to 10th	Day	37% 7% 9% 17% 20% 10%	4120
	11th to 20th	Day	36% 5% 8% 18% 28% 4	4086
	21st to end	Day	34% 9% 13% 23% 13% 8%	4489
June	1st to 10th	Day	23% 7% 14% 29% 22% 5%	2470
	11th to 20th	Day	21% 6% 13% 30% 21% 8%	2470
	21st to end	Day	24% 8% 12% 26% 23% 8%	2470
July	1st to 10th	Day	25% 7% 14% 39% 14% 1	4056
	11th to 20th	Day	17% 4 16% 36% 24% 3	4051
	21st to end	Day	23% 7% 13% 35% 20% 2	4325
August	1st to 10th	Day	13% 4 11% 33% 36% 4	4037
	11th to 20th	Day	19% 4 15% 34% 23% 4	3762
	21st to end	Day	21% 8% 16% 29% 22% 4	4148
September	1st to 10th	Day	32% 5% 10% 20% 23% 11%	2090
	11th to 20th	Day	33% 7% 11% 19% 24% 7%	2090
	21st to end	Day	25% 5% 9% 20% 25% 15%	2090
October	1st to 10th	Day	13% 3 7% 13% 32% 33%	3480
	11th to 20th	Day	18% 3 6% 22% 28% 23%	3304
	21st to end	Day	19% 3 3 22% 38% 15%	3428
November	1st to 10th	Day	30% 3 8% 21% 25% 14%	1873
	11th to 20th	Day	22% 4 8% 22% 27% 16%	1719
	21st to end	Day	34% 3 5% 19% 25% 14%	1710
December	1st to 10th	Day	34% 3 6% 17% 28% 12%	1710
	11th to 20th	Day	33% 5% 8% 14% 25% 15%	2159
	21st to end	Day	30% 3 5% 18% 28% 16%	3135
January	1st to 10th	Night	29% 2 5% 16% 33% 16%	4108
	11th to 20th	Night	24% 2 5% 19% 29% 21%	4120
	21st to end	Night	35% 4 6% 15% 25% 15%	4331
February	1st to 10th	Night	32% 4 8% 16% 22% 19%	2280
	11th to 20th	Night	32% 3 7% 16% 24% 18%	2218
	21st to end	Night	31% 4 5% 14% 22% 23%	1884
March	1st to 10th	Night	30% 4 8% 13% 27% 18%	3581
	11th to 20th	Night	34% 5% 13% 20% 17% 11%	3480
	21st to end	Night	30% 5% 12% 19% 25% 8%	3817
April	1st to 10th	Night	25% 6% 11% 20% 19% 20%	2090
	11th to 20th	Night	32% 6% 9% 15% 21% 16%	1909
	21st to end	Night	24% 5% 13% 21% 27% 10%	1777
May	1st to 10th	Night	37% 6% 9% 21% 16% 11%	2850
	11th to 20th	Night	30% 7% 11% 22% 23% 8%	2824
	21st to end	Night	28% 8% 13% 28% 16% 7%	3099
June	1st to 10th	Night	19% 6% 17% 32% 22% 4	1710
	11th to 20th	Night	16% 4 15% 34% 23% 8%	1710
	21st to end	Night	19% 6% 12% 29% 27% 8%	1710
July	1st to 10th	Night	18% 6% 14% 42% 17% 3	2805
	11th to 20th	Night	10% 3 14% 39% 30% 5%	2796
	21st to end	Night	19% 6% 13% 38% 22% 1	2999
August	1st to 10th	Night	10% 2 11% 31% 39% 5%	2874
	11th to 20th	Night	16% 4 17% 38% 22% 3	3143
	21st to end	Night	17% 7% 21% 28% 22% 4	3514
September	1st to 10th	Night	27% 6% 10% 23% 22% 12%	2090
	11th to 20th	Night	29% 6% 14% 21% 22% 9%	2090
	21st to end	Night	22% 4 9% 23% 24% 17%	2090
October	1st to 10th	Night	11% 3 7% 16% 26% 37%	3480
	11th to 20th	Night	17% 4 7% 17% 32% 23%	3582
	21st to end	Night	19% 2 3 23% 38% 15%	4120
November	1st to 10th	Night	26% 4 8% 20% 23% 19%	2420
	11th to 20th	Night	22% 5% 7% 22% 26% 18%	2484
	21st to end	Night	34% 3 6% 16% 25% 16%	2470
December	1st to 10th	Night	27% 5% 8% 20% 26% 14%	2470
	11th to 20th	Night	33% 4 6% 15% 26% 17%	3037
	21st to end	Night	31% 3 5% 15% 26% 19%	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	10% 14% 39% 30% 6% 1	270
	11th to 20th	Day	15% 14% 29% 31% 9% 2	270
	21st to end	Day	12% 12% 39% 26% 10% 1	297
February	1st to 10th	Day	15% 17% 38% 21% 9%	270
	11th to 20th	Day	22% 12% 39% 21% 5% 1	270
	21st to end	Day	20% 14% 44% 20% 1 1	225
March	1st to 10th	Day	12% 17% 39% 26% 6%	270
	11th to 20th	Day	15% 14% 37% 24% 7% 1	270
	21st to end	Day	9% 14% 47% 22% 7%	297
April	1st to 10th	Day	11% 16% 43% 21% 8%	270
	11th to 20th	Day	13% 14% 47% 21% 4	414
	21st to end	Day	10% 13% 43% 25% 8% 1	580
May	1st to 10th	Day	9% 12% 38% 35% 7%	653
	11th to 20th	Day	13% 8% 29% 31% 15% 4	675
	21st to end	Day	10% 7% 30% 34% 18% 2	734
June	1st to 10th	Day	5% 2 16% 42% 27% 7%	680
	11th to 20th	Day	3 1 18% 46% 26% 5%	680
	21st to end	Day	3 1 10% 36% 38% 11%	680
July	1st to 10th	Day	5% 1 8% 32% 40% 14%	671
	11th to 20th	Day	2 4 27% 48% 18%	668
	21st to end	Day	2 1 4 26% 47% 20%	739
August	1st to 10th	Day	1 3 26% 47% 22%	649
	11th to 20th	Day	8% 1 5% 25% 42% 19%	477
	21st to end	Day	2 1 4 28% 37% 27%	521
September	1st to 10th	Day	11% 1 6% 17% 36% 29%	300
	11th to 20th	Day	4 6% 22% 41% 26%	300
	21st to end	Day	11% 2 6% 26% 33% 22%	300
October	1st to 10th	Day	3 3 11% 35% 34% 14%	300
	11th to 20th	Day	10% 3 28% 31% 25% 4	300
	21st to end	Day	16% 10% 25% 21% 23% 4	330
November	1st to 10th	Day	14% 6% 30% 32% 12% 6%	300
	11th to 20th	Day	8% 12% 27% 32% 18% 4	273
	21st to end	Day	16% 15% 30% 26% 11% 2	270
December	1st to 10th	Day	15% 9% 29% 33% 12% 4	270
	11th to 20th	Day	10% 14% 41% 25% 10%	270
	21st to end	Day	22% 8% 35% 27% 7% 1	297
January	1st to 10th	Night	12% 8% 37% 36% 7%	950
	11th to 20th	Night	14% 9% 33% 36% 8%	950
	21st to end	Night	13% 11% 35% 35% 7%	922
February	1st to 10th	Night	14% 9% 42% 30% 5%	760
	11th to 20th	Night	16% 9% 42% 30% 3	744
	21st to end	Night	16% 12% 48% 22% 3	628
March	1st to 10th	Night	13% 12% 43% 28% 4	672
	11th to 20th	Night	13% 9% 45% 28% 5%	570
	21st to end	Night	9% 11% 47% 30% 4	627
April	1st to 10th	Night	6% 11% 54% 26% 4	570
	11th to 20th	Night	10% 10% 51% 26% 3	563
	21st to end	Night	7% 9% 53% 24% 7%	570
May	1st to 10th	Night	9% 11% 44% 32% 4	570
	11th to 20th	Night	8% 6% 40% 35% 11%	561
	21st to end	Night	8% 4 39% 38% 11% 1	617
June	1st to 10th	Night	3 2 26% 49% 19% 1	570
	11th to 20th	Night	3 1 26% 56% 14%	570
	21st to end	Night	4 1 16% 52% 26% 1	570
July	1st to 10th	Night	6% 1 8% 51% 30% 3	555
	11th to 20th	Night	4 7% 55% 33% 1	552
	21st to end	Night	2 5% 52% 39% 2	624
August	1st to 10th	Night	1 6% 51% 41% 2	567
	11th to 20th	Night	6% 1 6% 45% 39% 3	564
	21st to end	Night	3 1 5% 42% 44% 5%	627
September	1st to 10th	Night	7% 1 10% 47% 32% 4	570
	11th to 20th	Night	11% 1 8% 43% 36% 1	570
	21st to end	Night	7% 1 13% 45% 32% 2	570
October	1st to 10th	Night	5% 1 19% 47% 26% 2	570
	11th to 20th	Night	9% 5% 27% 42% 16% 1	641
	21st to end	Night	12% 8% 27% 35% 17% 1	836
November	1st to 10th	Night	10% 5% 28% 41% 15%	860
	11th to 20th	Night	6% 7% 32% 42% 13% 1	956
	21st to end	Night	16% 7% 34% 33% 10% 1	950
December	1st to 10th	Night	11% 7% 34% 39% 8% 1	950
	11th to 20th	Night	15% 7% 34% 37% 7%	950
	21st to end	Night	12% 8% 38% 34% 8%	1045

Page generated at 2024-11-08 21:45:34. Version ac07

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