Fort Parker State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Parker State Park clear sky chart from 2005-11-06 to 2025-01-22.

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 3 5% 7% 48%	105365
	Night	12% 5% 2 5% 3 3 3 3 5% 7% 53%	104125
Transparency	Day	35% 5% 10% 23% 20% 8%	109108
	Night	31% 4 9% 21% 22% 11%	108509
Seeing	Day	12% 6% 21% 28% 24% 9%	15255
	Night	13% 7% 26% 34% 17% 2	25241

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	13% 7% 2 5% 3 2 2 2 5% 7% 51%	2937
	11th to 20th	Day	16% 5% 2 3 2 2 3 2 4 6% 53%	2940
	21st to end	Day	23% 9% 4 6% 2 2 2 2 3 4 44%	3144
February	1st to 10th	Day	20% 7% 3 6% 3 3 3 2 4 6% 42%	1843
	11th to 20th	Day	18% 8% 2 5% 4 3 3 3 4 5% 44%	1849
	21st to end	Day	19% 7% 2 5% 3 3 3 2 3 4 48%	1632
March	1st to 10th	Day	16% 9% 3 7% 4 3 4 3 5% 6% 40%	3436
	11th to 20th	Day	18% 7% 2 7% 5% 5% 4 4 5% 6% 36%	3480
	21st to end	Day	15% 8% 2 7% 4 4 4 3 6% 7% 40%	3814
April	1st to 10th	Day	14% 7% 3 6% 4 4 4 4 6% 8% 42%	2090
	11th to 20th	Day	14% 7% 3 6% 5% 5% 4 4 6% 8% 40%	2161
	21st to end	Day	14% 5% 1 5% 4 4 4 4 5% 7% 47%	2336
May	1st to 10th	Day	20% 9% 3 7% 5% 4 5% 4 5% 7% 32%	4082
	11th to 20th	Day	15% 5% 2 7% 4 4 4 3 5% 7% 45%	4082
	21st to end	Day	12% 6% 2 8% 5% 5% 6% 4 8% 9% 35%	4477
June	1st to 10th	Day	5% 4 2 4 4 4 4 4 7% 11% 50%	2470
	11th to 20th	Day	5% 3 1 4 4 4 5% 4 7% 9% 52%	2470
	21st to end	Day	6% 4 2 4 5% 4 5% 4 7% 11% 49%	2470
July	1st to 10th	Day	7% 4 1 5% 4 4 5% 4 6% 9% 50%	4120
	11th to 20th	Day	3 3 1 4 3 4 4 4 7% 10% 57%	4120
	21st to end	Day	9% 8% 3 7% 5% 4 6% 4 8% 8% 38%	4465
August	1st to 10th	Day	2 1 1 2 2 2 3 3 6% 8% 70%	4104
	11th to 20th	Day	3 2 1 3 2 2 3 3 6% 9% 65%	4041
	21st to end	Day	4 3 1 4 4 4 6% 5% 7% 11% 51%	3977
September	1st to 10th	Day	9% 5% 3 6% 4 4 5% 4 6% 7% 48%	2090
	11th to 20th	Day	10% 4 2 6% 4 4 4 4 6% 7% 48%	2090
	21st to end	Day	7% 3 1 4 3 4 5% 4 5% 7% 56%	2090
October	1st to 10th	Day	6% 3 1 4 3 3 4 3 4 7% 62%	2033
	11th to 20th	Day	13% 4 1 3 3 2 3 2 4 5% 59%	1900
	21st to end	Day	14% 3 2 3 3 3 3 2 3 4 60%	2090
November	1st to 10th	Day	12% 7% 2 6% 4 3 4 3 4 6% 49%	1958
	11th to 20th	Day	9% 4 2 5% 4 3 4 4 4 6% 54%	1955
	21st to end	Day	16% 7% 2 5% 4 3 4 3 4 6% 48%	1800
December	1st to 10th	Day	19% 6% 2 5% 3 2 3 3 4 5% 47%	2940
	11th to 20th	Day	17% 8% 2 6% 4 4 3 3 5% 6% 41%	3391
	21st to end	Day	14% 9% 3 6% 4 3 3 2 3 5% 48%	4488
January	1st to 10th	Night	16% 5% 2 4 2 3 2 2 4 5% 57%	4238
	11th to 20th	Night	14% 5% 1 3 2 2 2 2 3 4 60%	4250
	21st to end	Night	20% 7% 3 6% 3 3 3 2 3 5% 45%	4546
February	1st to 10th	Night	18% 7% 2 5% 3 3 3 3 4 5% 47%	2352
	11th to 20th	Night	18% 7% 2 5% 4 3 3 2 3 5% 48%	2218
	21st to end	Night	18% 7% 2 5% 4 3 2 3 4 5% 48%	1819
March	1st to 10th	Night	16% 9% 3 7% 4 4 4 3 6% 6% 39%	3419
	11th to 20th	Night	17% 8% 2 6% 4 4 4 4 5% 6% 39%	3480
	21st to end	Night	13% 6% 3 6% 4 4 4 3 5% 6% 46%	3817
April	1st to 10th	Night	11% 6% 2 6% 3 3 3 4 5% 7% 51%	2090
	11th to 20th	Night	13% 5% 3 4 5% 4 3 3 5% 7% 48%	1965
	21st to end	Night	12% 5% 2 5% 4 3 3 3 6% 7% 51%	1838
May	1st to 10th	Night	18% 8% 2 6% 4 3 4 3 5% 8% 39%	2823
	11th to 20th	Night	12% 6% 2 6% 4 4 4 4 5% 6% 47%	2823
	21st to end	Night	10% 6% 2 6% 4 4 5% 4 6% 9% 45%	3090
June	1st to 10th	Night	5% 2 1 4 2 3 4 4 7% 9% 58%	1710
	11th to 20th	Night	4 2 1 3 2 2 3 3 5% 9% 65%	1710
	21st to end	Night	4 3 1 4 4 4 4 4 6% 8% 57%	1710
July	1st to 10th	Night	4 3 1 4 3 3 4 4 6% 11% 56%	2850
	11th to 20th	Night	3 2 1 3 3 2 4 4 6% 11% 62%	2850
	21st to end	Night	5% 8% 2 6% 4 4 5% 5% 7% 9% 44%	3098
August	1st to 10th	Night	1 1 1 1 1 1 2 4 9% 80%	2836
	11th to 20th	Night	4 2 1 3 2 2 3 4 6% 10% 64%	2798
	21st to end	Night	2 2 1 3 3 3 4 4 7% 12% 58%	3673
September	1st to 10th	Night	8% 4 2 4 4 3 4 3 6% 8% 54%	2090
	11th to 20th	Night	10% 5% 3 4 3 3 4 3 6% 6% 53%	2090
	21st to end	Night	6% 3 2 3 3 3 3 3 4 9% 61%	2090
October	1st to 10th	Night	5% 3 1 3 2 2 3 3 4 6% 68%	2127
	11th to 20th	Night	12% 4 1 3 3 3 3 2 4 6% 60%	2280
	21st to end	Night	13% 4 2 4 3 2 2 2 3 4 61%	2508
November	1st to 10th	Night	11% 6% 2 5% 2 3 3 2 3 6% 57%	2340
	11th to 20th	Night	9% 4 2 5% 3 3 4 3 4 6% 58%	2441
	21st to end	Night	17% 6% 2 4 3 3 4 3 4 5% 50%	2600
December	1st to 10th	Night	19% 6% 2 5% 3 2 3 2 4 5% 48%	4250
	11th to 20th	Night	19% 8% 3 6% 3 2 3 2 3 5% 46%	4816
	21st to end	Night	15% 7% 2 5% 3 2 2 2 3 4 55%	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	34% 4 5% 20% 30% 7%	2938
	11th to 20th	Day	33% 4 6% 23% 26% 7%	2940
	21st to end	Day	48% 2 3 16% 21% 10%	3144
February	1st to 10th	Day	45% 5% 5% 13% 21% 11%	1843
	11th to 20th	Day	44% 4 6% 16% 20% 10%	1859
	21st to end	Day	43% 3 4 16% 18% 15%	1632
March	1st to 10th	Day	44% 6% 6% 16% 22% 7%	3436
	11th to 20th	Day	48% 7% 10% 14% 15% 6%	3480
	21st to end	Day	42% 6% 9% 18% 20% 5%	3814
April	1st to 10th	Day	41% 7% 8% 19% 14% 11%	2090
	11th to 20th	Day	43% 5% 9% 16% 18% 9%	2161
	21st to end	Day	36% 5% 9% 20% 23% 6%	2336
May	1st to 10th	Day	51% 7% 9% 19% 11% 4	4120
	11th to 20th	Day	40% 7% 8% 19% 26% 1	4086
	21st to end	Day	41% 10% 12% 23% 12% 2	4489
June	1st to 10th	Day	27% 7% 15% 31% 17% 3	2470
	11th to 20th	Day	26% 7% 15% 30% 16% 5%	2470
	21st to end	Day	30% 7% 14% 28% 20% 2	2470
July	1st to 10th	Day	30% 6% 23% 32% 9%	4056
	11th to 20th	Day	23% 4 16% 37% 18% 2	4051
	21st to end	Day	41% 5% 15% 28% 10%	4325
August	1st to 10th	Day	12% 3 11% 39% 32% 2	4090
	11th to 20th	Day	16% 4 19% 42% 17% 2	4080
	21st to end	Day	27% 6% 21% 30% 14% 2	3976
September	1st to 10th	Day	35% 6% 12% 19% 18% 10%	2090
	11th to 20th	Day	35% 7% 12% 20% 18% 7%	2090
	21st to end	Day	27% 5% 9% 23% 21% 14%	2090
October	1st to 10th	Day	15% 3 7% 12% 24% 41%	3384
	11th to 20th	Day	18% 2 5% 19% 31% 24%	3140
	21st to end	Day	27% 2 3 24% 32% 11%	3428
November	1st to 10th	Day	37% 5% 8% 18% 22% 11%	1958
	11th to 20th	Day	31% 5% 8% 17% 24% 15%	1955
	21st to end	Day	40% 5% 6% 18% 20% 12%	1800
December	1st to 10th	Day	41% 3 6% 20% 23% 8%	2940
	11th to 20th	Day	45% 3 5% 12% 25% 10%	3389
	21st to end	Day	42% 2 4 16% 27% 10%	4488
January	1st to 10th	Night	32% 4 5% 18% 31% 12%	4238
	11th to 20th	Night	30% 4 5% 16% 31% 14%	4250
	21st to end	Night	44% 3 4 15% 23% 11%	4546
February	1st to 10th	Night	42% 4 5% 13% 20% 16%	2352
	11th to 20th	Night	41% 3 6% 15% 23% 13%	2218
	21st to end	Night	40% 4 8% 14% 18% 17%	1819
March	1st to 10th	Night	45% 7% 6% 13% 21% 9%	3419
	11th to 20th	Night	45% 7% 9% 18% 16% 6%	3480
	21st to end	Night	38% 5% 8% 18% 24% 7%	3817
April	1st to 10th	Night	32% 6% 9% 21% 18% 14%	2090
	11th to 20th	Night	36% 5% 11% 17% 18% 14%	1965
	21st to end	Night	33% 5% 10% 17% 26% 8%	1838
May	1st to 10th	Night	44% 7% 10% 21% 13% 5%	2850
	11th to 20th	Night	37% 6% 11% 19% 23% 3	2824
	21st to end	Night	34% 9% 13% 28% 11% 5%	3099
June	1st to 10th	Night	21% 8% 16% 32% 21% 3	1710
	11th to 20th	Night	17% 6% 15% 35% 21% 6%	1710
	21st to end	Night	25% 7% 14% 27% 23% 4	1710
July	1st to 10th	Night	23% 5% 25% 39% 7% 1	2805
	11th to 20th	Night	19% 4 19% 40% 16% 2	2796
	21st to end	Night	35% 6% 20% 30% 9% 1	2999
August	1st to 10th	Night	6% 3 12% 36% 38% 4	2826
	11th to 20th	Night	17% 4 21% 40% 14% 3	2825
	21st to end	Night	19% 7% 23% 33% 15% 3	3673
September	1st to 10th	Night	29% 6% 14% 22% 18% 11%	2090
	11th to 20th	Night	31% 6% 14% 20% 21% 9%	2090
	21st to end	Night	22% 5% 11% 22% 25% 15%	2090
October	1st to 10th	Night	13% 3 6% 15% 20% 44%	3543
	11th to 20th	Night	17% 2 4 17% 33% 27%	3779
	21st to end	Night	23% 2 3 21% 34% 17%	4120
November	1st to 10th	Night	31% 4 7% 19% 24% 14%	2340
	11th to 20th	Night	30% 4 7% 19% 24% 16%	2441
	21st to end	Night	38% 3 7% 17% 22% 13%	2600
December	1st to 10th	Night	40% 2 5% 19% 24% 9%	4250
	11th to 20th	Night	44% 2 6% 10% 25% 13%	4817
	21st to end	Night	36% 2 3 17% 29% 13%	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	20% 12% 36% 23% 9%	300
	11th to 20th	Day	22% 12% 34% 25% 7% 1	300
	21st to end	Day	22% 13% 37% 20% 7% 1	300
February	1st to 10th	Day	24% 17% 30% 24% 5%	270
	11th to 20th	Day	25% 18% 34% 18% 4	270
	21st to end	Day	26% 18% 38% 16% 2	225
March	1st to 10th	Day	21% 13% 38% 21% 6%	270
	11th to 20th	Day	18% 18% 38% 20% 5% 1	270
	21st to end	Day	15% 12% 45% 21% 6% 1	297
April	1st to 10th	Day	20% 17% 36% 21% 5%	270
	11th to 20th	Day	21% 14% 33% 22% 9% 1	359
	21st to end	Day	16% 10% 36% 29% 8% 1	516
May	1st to 10th	Day	12% 13% 34% 32% 8% 1	653
	11th to 20th	Day	16% 5% 24% 33% 18% 4	675
	21st to end	Day	13% 6% 26% 32% 19% 4	734
June	1st to 10th	Day	5% 2 13% 42% 27% 11%	680
	11th to 20th	Day	6% 15% 41% 30% 8%	680
	21st to end	Day	4 1 12% 31% 36% 15%	680
July	1st to 10th	Day	6% 1 8% 34% 35% 16%	671
	11th to 20th	Day	2 1 4 33% 45% 15%	668
	21st to end	Day	6% 4 28% 47% 15%	739
August	1st to 10th	Day	2 3 31% 45% 19%	676
	11th to 20th	Day	6% 3 26% 47% 16%	665
	21st to end	Day	6% 1 4 18% 40% 30%	427
September	1st to 10th	Day	9% 1 6% 22% 36% 27%	300
	11th to 20th	Day	6% 1 7% 23% 43% 22%	300
	21st to end	Day	8% 2 8% 27% 35% 20%	300
October	1st to 10th	Day	3 2 15% 30% 38% 12%	300
	11th to 20th	Day	11% 7% 18% 32% 25% 7%	300
	21st to end	Day	21% 9% 23% 24% 17% 6%	330
November	1st to 10th	Day	21% 4 25% 31% 14% 5%	300
	11th to 20th	Day	15% 7% 29% 29% 18% 3	300
	21st to end	Day	19% 14% 29% 25% 11% 2	300
December	1st to 10th	Day	18% 8% 27% 30% 14% 3	300
	11th to 20th	Day	23% 11% 33% 27% 5% 1	300
	21st to end	Day	22% 8% 39% 20% 8% 1	330
January	1st to 10th	Night	19% 11% 35% 29% 7%	1000
	11th to 20th	Night	19% 12% 34% 29% 6%	1000
	21st to end	Night	19% 12% 33% 31% 6%	1051
February	1st to 10th	Night	23% 13% 33% 27% 3	832
	11th to 20th	Night	24% 11% 39% 24% 3	744
	21st to end	Night	23% 17% 40% 18% 2	563
March	1st to 10th	Night	19% 14% 38% 25% 5%	570
	11th to 20th	Night	17% 9% 40% 27% 6%	570
	21st to end	Night	15% 12% 41% 27% 4	627
April	1st to 10th	Night	11% 12% 44% 29% 5%	570
	11th to 20th	Night	14% 14% 40% 25% 8%	563
	21st to end	Night	14% 8% 43% 25% 10% 1	570
May	1st to 10th	Night	11% 9% 41% 30% 8% 1	570
	11th to 20th	Night	12% 6% 33% 34% 14% 1	561
	21st to end	Night	8% 5% 30% 41% 15% 2	617
June	1st to 10th	Night	5% 2 18% 41% 31% 3	570
	11th to 20th	Night	5% 1 19% 55% 20% 1	570
	21st to end	Night	5% 1 13% 44% 33% 5%	570
July	1st to 10th	Night	4 10% 45% 37% 4	555
	11th to 20th	Night	3 8% 50% 35% 4	552
	21st to end	Night	3 5% 48% 41% 3	624
August	1st to 10th	Night	1 4 47% 43% 4	567
	11th to 20th	Night	8% 5% 45% 38% 4	564
	21st to end	Night	4 5% 38% 45% 8%	627
September	1st to 10th	Night	10% 1 7% 39% 38% 5%	570
	11th to 20th	Night	12% 1 6% 37% 40% 4	570
	21st to end	Night	8% 2 9% 38% 39% 5%	570
October	1st to 10th	Night	5% 2 14% 49% 25% 5%	607
	11th to 20th	Night	14% 3 22% 39% 20% 2	760
	21st to end	Night	14% 9% 28% 31% 17% 1	836
November	1st to 10th	Night	13% 5% 27% 37% 17% 2	780
	11th to 20th	Night	9% 9% 29% 39% 13% 1	841
	21st to end	Night	19% 10% 29% 30% 12% 1	1000
December	1st to 10th	Night	17% 8% 32% 33% 8% 1	1000
	11th to 20th	Night	22% 10% 30% 32% 7%	1000
	21st to end	Night	20% 9% 32% 30% 8%	1100

Page generated at 2025-01-19 02:06:46. Version ac07

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