Bonham State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bonham State Park clear sky chart from 2005-11-06 to 2025-02-06.

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% 5% 2 5% 4 4 4 3 5% 7% 50%	109141
	Night	11% 5% 2 4 3 3 3 3 5% 6% 55%	109337
Transparency	Day	35% 3 9% 25% 22% 7%	112845
	Night	31% 2 8% 24% 25% 10%	113747
Seeing	Day	13% 5% 22% 29% 23% 8%	15502
	Night	13% 6% 27% 35% 17% 2	25507

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% 6% 3 5% 3 3 2 2 3 6% 52%	4077
	11th to 20th	Day	9% 5% 2 4 2 2 2 2 4 5% 64%	4080
	21st to end	Day	21% 7% 2 6% 3 2 2 2 3 4 46%	4488
February	1st to 10th	Day	18% 8% 3 7% 3 3 3 2 3 5% 44%	1793
	11th to 20th	Day	17% 7% 3 5% 4 3 3 3 5% 5% 46%	1849
	21st to end	Day	21% 8% 2 4 3 3 2 2 3 3 49%	1632
March	1st to 10th	Day	15% 6% 2 5% 3 3 3 3 4 6% 49%	3436
	11th to 20th	Day	16% 7% 3 6% 4 4 4 4 5% 5% 42%	3480
	21st to end	Day	17% 8% 3 6% 4 4 4 4 5% 7% 39%	3814
April	1st to 10th	Day	13% 6% 2 6% 5% 3 4 4 5% 5% 48%	2090
	11th to 20th	Day	15% 6% 2 6% 5% 3 3 3 5% 7% 45%	2216
	21st to end	Day	13% 6% 2 5% 5% 4 3 4 6% 6% 45%	2366
May	1st to 10th	Day	18% 7% 2 6% 5% 4 4 3 5% 6% 39%	4082
	11th to 20th	Day	15% 6% 2 5% 4 4 3 3 5% 5% 48%	4082
	21st to end	Day	16% 8% 3 7% 6% 5% 4 3 6% 6% 35%	4477
June	1st to 10th	Day	6% 5% 2 6% 5% 5% 5% 5% 8% 9% 45%	2470
	11th to 20th	Day	5% 4 1 6% 5% 5% 6% 4 7% 7% 49%	2470
	21st to end	Day	5% 3 1 5% 4 4 5% 4 7% 9% 53%	2470
July	1st to 10th	Day	6% 5% 2 6% 5% 4 4 4 6% 9% 48%	4120
	11th to 20th	Day	3 3 1 3 3 3 4 4 7% 10% 58%	4120
	21st to end	Day	6% 6% 3 6% 5% 6% 6% 5% 8% 10% 40%	4465
August	1st to 10th	Day	2 2 1 4 3 3 3 3 6% 7% 66%	4104
	11th to 20th	Day	5% 3 1 4 3 4 5% 4 6% 9% 56%	4041
	21st to end	Day	3 3 2 4 4 4 6% 5% 8% 10% 50%	4185
September	1st to 10th	Day	9% 4 2 5% 5% 5% 4 3 4 7% 53%	2090
	11th to 20th	Day	10% 4 2 7% 4 4 5% 4 5% 7% 47%	2090
	21st to end	Day	7% 3 2 4 3 3 3 3 6% 7% 59%	2090
October	1st to 10th	Day	5% 3 2 5% 4 3 3 4 5% 6% 60%	1993
	11th to 20th	Day	12% 4 2 4 2 2 2 2 3 5% 62%	1900
	21st to end	Day	14% 5% 2 5% 2 3 3 2 3 4 57%	2090
November	1st to 10th	Day	13% 4 2 4 3 4 3 3 5% 6% 54%	1958
	11th to 20th	Day	8% 4 2 5% 3 4 3 3 4 6% 59%	1904
	21st to end	Day	13% 7% 2 5% 3 3 2 2 3 4 55%	1800
December	1st to 10th	Day	17% 7% 2 4 3 2 2 2 3 5% 53%	2940
	11th to 20th	Day	18% 8% 3 6% 3 3 3 2 3 4 46%	3391
	21st to end	Day	21% 8% 2 4 2 3 3 2 4 5% 47%	4488
January	1st to 10th	Night	16% 5% 1 4 3 3 3 2 4 5% 55%	5888
	11th to 20th	Night	7% 4 1 3 2 2 2 2 3 5% 70%	5900
	21st to end	Night	23% 7% 2 5% 3 2 2 2 3 4 47%	6490
February	1st to 10th	Night	15% 6% 2 6% 3 3 3 3 3 5% 50%	2515
	11th to 20th	Night	16% 7% 3 5% 4 2 4 4 4 5% 48%	2218
	21st to end	Night	18% 6% 2 4 3 3 3 2 3 4 53%	1822
March	1st to 10th	Night	16% 8% 2 6% 4 4 4 3 5% 6% 43%	3419
	11th to 20th	Night	13% 7% 2 5% 4 4 3 2 5% 6% 48%	3480
	21st to end	Night	14% 7% 2 6% 4 4 3 3 5% 6% 46%	3817
April	1st to 10th	Night	10% 5% 2 4 4 3 3 4 5% 7% 52%	2090
	11th to 20th	Night	13% 6% 2 5% 4 4 4 3 5% 6% 49%	1911
	21st to end	Night	12% 4 2 5% 3 3 3 3 5% 7% 54%	1810
May	1st to 10th	Night	17% 8% 2 6% 4 4 4 3 6% 6% 39%	2823
	11th to 20th	Night	12% 6% 2 6% 3 3 3 3 5% 8% 49%	2823
	21st to end	Night	11% 6% 2 5% 4 4 5% 4 7% 8% 44%	3090
June	1st to 10th	Night	5% 3 1 4 2 4 3 4 6% 10% 58%	1710
	11th to 20th	Night	4 3 1 3 3 3 3 3 5% 10% 62%	1710
	21st to end	Night	2 2 1 3 3 3 3 3 5% 11% 62%	1710
July	1st to 10th	Night	5% 3 1 4 3 3 4 4 8% 11% 54%	2850
	11th to 20th	Night	3 2 1 3 2 2 3 3 6% 10% 64%	2850
	21st to end	Night	3 4 2 5% 4 3 4 4 7% 9% 54%	3098
August	1st to 10th	Night	2 1 1 2 1 2 2 3 5% 8% 73%	2836
	11th to 20th	Night	3 2 1 3 2 2 2 3 6% 11% 66%	2798
	21st to end	Night	2 2 1 3 3 3 4 3 7% 10% 60%	3466
September	1st to 10th	Night	6% 5% 2 4 4 2 3 3 5% 7% 58%	2090
	11th to 20th	Night	10% 5% 1 4 3 3 3 3 5% 6% 55%	2090
	21st to end	Night	6% 3 2 3 3 2 3 3 6% 6% 64%	2090
October	1st to 10th	Night	6% 3 1 4 2 3 3 3 4 5% 66%	2166
	11th to 20th	Night	11% 4 1 3 2 3 3 2 4 5% 62%	2280
	21st to end	Night	14% 5% 2 4 3 2 2 1 3 4 60%	2508
November	1st to 10th	Night	11% 4 1 5% 3 3 3 3 3 4 59%	2340
	11th to 20th	Night	7% 4 2 3 3 3 3 3 5% 7% 59%	2493
	21st to end	Night	14% 6% 2 4 3 2 3 3 4 6% 54%	2600
December	1st to 10th	Night	14% 7% 2 5% 2 3 3 3 3 4 54%	4250
	11th to 20th	Night	16% 6% 3 6% 3 3 3 2 3 3 51%	4816
	21st to end	Night	16% 8% 3 5% 3 3 2 2 3 4 50%	6490

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	37% 2 6% 28% 24% 3	4078
	11th to 20th	Day	25% 1 6% 23% 37% 7%	4080
	21st to end	Day	45% 1 3 17% 22% 12%	4488
February	1st to 10th	Day	45% 3 6% 19% 21% 7%	1793
	11th to 20th	Day	42% 2 7% 24% 18% 8%	1859
	21st to end	Day	42% 2 4 16% 26% 10%	1632
March	1st to 10th	Day	38% 2 6% 18% 26% 10%	3436
	11th to 20th	Day	45% 2 11% 22% 17% 4	3480
	21st to end	Day	46% 2 8% 22% 19% 3	3814
April	1st to 10th	Day	38% 4 8% 23% 19% 9%	2090
	11th to 20th	Day	39% 3 10% 20% 20% 8%	2216
	21st to end	Day	39% 4 8% 23% 22% 4	2366
May	1st to 10th	Day	48% 3 7% 23% 16% 4	4120
	11th to 20th	Day	39% 3 10% 28% 20% 1	4086
	21st to end	Day	49% 3 11% 19% 13% 4	4489
June	1st to 10th	Day	34% 5% 14% 27% 17% 3	2470
	11th to 20th	Day	32% 4 13% 27% 20% 4	2470
	21st to end	Day	26% 5% 11% 32% 23% 3	2470
July	1st to 10th	Day	33% 4 15% 36% 12% 1	4056
	11th to 20th	Day	21% 4 10% 40% 24% 2	4051
	21st to end	Day	37% 3 13% 33% 13%	4325
August	1st to 10th	Day	18% 2 12% 28% 30% 10%	4090
	11th to 20th	Day	25% 3 15% 39% 17% 2	4080
	21st to end	Day	26% 4 18% 36% 13% 2	4184
September	1st to 10th	Day	32% 3 9% 24% 20% 12%	2090
	11th to 20th	Day	35% 4 10% 21% 21% 8%	2090
	21st to end	Day	25% 3 8% 23% 30% 11%	2090
October	1st to 10th	Day	16% 2 6% 13% 35% 28%	3305
	11th to 20th	Day	20% 1 3 19% 36% 21%	3140
	21st to end	Day	28% 2 4 32% 26% 9%	3428
November	1st to 10th	Day	32% 2 8% 23% 25% 9%	1958
	11th to 20th	Day	29% 2 7% 21% 29% 12%	1904
	21st to end	Day	35% 1 5% 19% 30% 9%	1800
December	1st to 10th	Day	37% 1 5% 30% 23% 4	2940
	11th to 20th	Day	44% 1 3 16% 27% 8%	3389
	21st to end	Day	43% 2 3 23% 22% 6%	4488
January	1st to 10th	Night	34% 2 5% 27% 27% 5%	5888
	11th to 20th	Night	21% 1 7% 21% 36% 14%	5900
	21st to end	Night	45% 1 4 14% 24% 12%	6490
February	1st to 10th	Night	38% 3 7% 20% 23% 10%	2515
	11th to 20th	Night	40% 3 6% 20% 23% 9%	2218
	21st to end	Night	37% 2 6% 17% 23% 15%	1822
March	1st to 10th	Night	43% 2 6% 16% 20% 12%	3419
	11th to 20th	Night	39% 2 9% 23% 18% 9%	3480
	21st to end	Night	40% 3 8% 19% 28% 3	3817
April	1st to 10th	Night	32% 3 10% 23% 19% 14%	2090
	11th to 20th	Night	37% 3 7% 21% 20% 12%	1911
	21st to end	Night	31% 3 11% 23% 26% 5%	1810
May	1st to 10th	Night	46% 3 9% 20% 15% 7%	2850
	11th to 20th	Night	34% 3 14% 25% 22% 2	2824
	21st to end	Night	38% 4 16% 23% 13% 7%	3099
June	1st to 10th	Night	22% 4 16% 33% 21% 4	1710
	11th to 20th	Night	20% 3 14% 34% 23% 7%	1710
	21st to end	Night	18% 4 13% 32% 27% 5%	1710
July	1st to 10th	Night	24% 4 18% 37% 16% 2	2805
	11th to 20th	Night	16% 3 9% 43% 26% 3	2796
	21st to end	Night	26% 3 16% 35% 19% 1	2999
August	1st to 10th	Night	11% 2 9% 31% 39% 7%	2826
	11th to 20th	Night	15% 2 14% 42% 21% 6%	2825
	21st to end	Night	20% 4 17% 36% 20% 3	3466
September	1st to 10th	Night	26% 3 11% 23% 26% 11%	2090
	11th to 20th	Night	30% 4 9% 23% 23% 10%	2090
	21st to end	Night	22% 2 8% 24% 29% 15%	2090
October	1st to 10th	Night	13% 2 5% 14% 33% 33%	3608
	11th to 20th	Night	18% 2 4 15% 36% 25%	3779
	21st to end	Night	27% 2 3 29% 25% 15%	4120
November	1st to 10th	Night	31% 3 6% 21% 25% 15%	2340
	11th to 20th	Night	27% 2 8% 21% 27% 15%	2493
	21st to end	Night	33% 2 7% 19% 29% 10%	2600
December	1st to 10th	Night	35% 2 5% 24% 26% 7%	4250
	11th to 20th	Night	42% 1 4 15% 24% 14%	4817
	21st to end	Night	40% 2 5% 20% 26% 7%	6490

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% 11% 34% 24% 7%	300
	11th to 20th	Day	18% 14% 41% 20% 6% 1	300
	21st to end	Day	21% 10% 38% 22% 8% 1	330
February	1st to 10th	Day	24% 10% 36% 24% 5% 1	285
	11th to 20th	Day	23% 15% 41% 17% 4	270
	21st to end	Day	29% 15% 42% 11% 3	225
March	1st to 10th	Day	24% 10% 39% 22% 5%	270
	11th to 20th	Day	21% 15% 37% 21% 4 2	270
	21st to end	Day	18% 14% 42% 18% 7%	297
April	1st to 10th	Day	15% 14% 37% 29% 4 1	270
	11th to 20th	Day	23% 9% 35% 24% 8%	414
	21st to end	Day	19% 11% 37% 24% 7% 2	546
May	1st to 10th	Day	15% 8% 32% 34% 10% 1	653
	11th to 20th	Day	16% 4 27% 35% 14% 4	675
	21st to end	Day	16% 4 24% 33% 18% 4	734
June	1st to 10th	Day	9% 2 12% 36% 33% 9%	680
	11th to 20th	Day	8% 2 14% 40% 28% 9%	680
	21st to end	Day	5% 1 10% 37% 34% 13%	680
July	1st to 10th	Day	6% 1 7% 32% 37% 16%	671
	11th to 20th	Day	4 1 5% 31% 46% 13%	668
	21st to end	Day	5% 1 4 30% 42% 18%	739
August	1st to 10th	Day	3 5% 30% 47% 14%	676
	11th to 20th	Day	10% 4 32% 41% 12%	665
	21st to end	Day	6% 4 25% 41% 23%	544
September	1st to 10th	Day	9% 3 22% 41% 25%	300
	11th to 20th	Day	4 1 7% 28% 40% 21%	300
	21st to end	Day	10% 1 9% 30% 32% 18%	300
October	1st to 10th	Day	3 2 19% 32% 34% 10%	300
	11th to 20th	Day	14% 4 23% 37% 20% 3	300
	21st to end	Day	22% 6% 26% 27% 17% 2	330
November	1st to 10th	Day	19% 6% 31% 26% 14% 4	300
	11th to 20th	Day	13% 9% 32% 30% 13% 2	300
	21st to end	Day	17% 12% 36% 23% 11% 2	300
December	1st to 10th	Day	20% 10% 32% 27% 11% 1	300
	11th to 20th	Day	22% 8% 39% 25% 7%	300
	21st to end	Day	22% 14% 36% 22% 5% 1	330
January	1st to 10th	Night	15% 9% 38% 31% 7%	1000
	11th to 20th	Night	16% 14% 36% 28% 6% 1	1000
	21st to end	Night	17% 8% 37% 31% 6%	1100
February	1st to 10th	Night	19% 10% 38% 28% 5%	955
	11th to 20th	Night	21% 11% 39% 26% 3	744
	21st to end	Night	24% 13% 40% 21% 2	566
March	1st to 10th	Night	20% 11% 35% 28% 7%	570
	11th to 20th	Night	16% 9% 40% 28% 8%	570
	21st to end	Night	15% 12% 37% 31% 5%	627
April	1st to 10th	Night	13% 11% 42% 29% 6%	570
	11th to 20th	Night	16% 9% 38% 31% 7%	563
	21st to end	Night	13% 7% 41% 30% 9% 1	570
May	1st to 10th	Night	12% 7% 36% 36% 8% 1	570
	11th to 20th	Night	12% 4 30% 35% 18% 2	561
	21st to end	Night	8% 3 26% 42% 20% 1	617
June	1st to 10th	Night	7% 2 12% 44% 31% 4	570
	11th to 20th	Night	5% 1 19% 51% 23% 1	570
	21st to end	Night	3 15% 43% 35% 4	570
July	1st to 10th	Night	4 2 8% 43% 37% 7%	555
	11th to 20th	Night	4 7% 43% 41% 5%	552
	21st to end	Night	2 1 4 43% 44% 6%	624
August	1st to 10th	Night	3 5% 44% 43% 5%	567
	11th to 20th	Night	7% 5% 41% 41% 5%	564
	21st to end	Night	4 1 4 40% 44% 8%	627
September	1st to 10th	Night	9% 1 6% 38% 41% 5%	570
	11th to 20th	Night	12% 1 6% 41% 37% 4	570
	21st to end	Night	8% 12% 42% 32% 6%	570
October	1st to 10th	Night	7% 1 19% 42% 28% 2	646
	11th to 20th	Night	14% 4 25% 40% 16% 2	760
	21st to end	Night	17% 6% 30% 31% 14% 1	836
November	1st to 10th	Night	13% 3 28% 40% 14% 1	780
	11th to 20th	Night	9% 8% 33% 37% 12% 1	893
	21st to end	Night	17% 9% 35% 29% 10%	1000
December	1st to 10th	Night	16% 8% 34% 35% 7%	1000
	11th to 20th	Night	21% 7% 34% 32% 6%	1000
	21st to end	Night	19% 9% 36% 29% 7%	1100

Page generated at 2025-02-03 02:05:49. Version ac07

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