Staunton River State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Staunton River State Park clear sky chart from 2005-11-06 to 2024-11-25.

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% 6% 2 6% 4 4 4 4 6% 8% 43%	100959
	Night	14% 6% 2 6% 4 4 4 4 5% 7% 44%	98454
Transparency	Day	37% 7% 12% 22% 17% 4	104608
	Night	38% 6% 10% 21% 19% 5%	102944
Seeing	Day	17% 11% 25% 25% 16% 6%	15273
	Night	16% 10% 26% 30% 16% 2	25304

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% 5% 2 4 3 2 3 3 4 5% 52%	2836
	11th to 20th	Day	14% 7% 3 5% 3 2 3 3 4 5% 51%	2840
	21st to end	Day	20% 10% 3 6% 3 4 4 3 4 5% 40%	3124
February	1st to 10th	Day	13% 6% 2 6% 5% 5% 4 5% 5% 8% 42%	1710
	11th to 20th	Day	21% 6% 1 4 4 4 4 3 5% 5% 45%	1671
	21st to end	Day	19% 6% 2 6% 4 4 4 4 5% 7% 38%	1679
March	1st to 10th	Day	21% 8% 2 5% 4 4 3 3 5% 7% 36%	3435
	11th to 20th	Day	10% 5% 2 4 3 3 4 4 4 7% 54%	3480
	21st to end	Day	20% 6% 2 5% 4 4 4 3 5% 6% 40%	3815
April	1st to 10th	Day	10% 5% 2 4 3 3 4 4 6% 7% 53%	2226
	11th to 20th	Day	10% 6% 2 6% 4 4 5% 3 4 7% 50%	2254
	21st to end	Day	14% 6% 2 6% 4 4 4 4 5% 6% 45%	2280
May	1st to 10th	Day	13% 7% 2 8% 5% 5% 6% 4 7% 9% 33%	4072
	11th to 20th	Day	18% 6% 3 8% 4 4 4 4 7% 8% 33%	4081
	21st to end	Day	9% 4 2 5% 4 5% 4 4 6% 10% 47%	4476
June	1st to 10th	Day	9% 5% 2 5% 4 5% 5% 5% 7% 10% 43%	2608
	11th to 20th	Day	8% 4 2 6% 4 5% 5% 4 8% 9% 45%	2660
	21st to end	Day	7% 4 2 5% 5% 5% 6% 5% 7% 11% 41%	2511
July	1st to 10th	Day	6% 4 2 7% 5% 6% 6% 5% 9% 12% 38%	4120
	11th to 20th	Day	11% 5% 2 6% 4 5% 6% 5% 8% 12% 36%	4120
	21st to end	Day	11% 7% 3 8% 6% 6% 6% 5% 8% 9% 30%	4466
August	1st to 10th	Day	16% 8% 3 7% 5% 5% 5% 5% 7% 11% 27%	4104
	11th to 20th	Day	8% 7% 2 6% 5% 5% 5% 5% 7% 11% 37%	3926
	21st to end	Day	7% 4 2 5% 4 4 5% 3 5% 10% 51%	4180
September	1st to 10th	Day	10% 5% 2 5% 4 5% 5% 4 6% 8% 46%	2280
	11th to 20th	Day	13% 6% 2 6% 5% 4 5% 4 6% 7% 42%	2179
	21st to end	Day	21% 7% 2 6% 4 4 4 4 4 6% 38%	2035
October	1st to 10th	Day	15% 5% 3 5% 3 3 3 2 3 6% 51%	1900
	11th to 20th	Day	14% 4 2 4 3 3 3 2 4 5% 56%	1900
	21st to end	Day	11% 4 2 6% 3 4 3 3 3 6% 55%	2090
November	1st to 10th	Day	12% 5% 2 4 3 4 3 3 4 6% 54%	1957
	11th to 20th	Day	14% 5% 2 4 3 3 4 3 5% 6% 50%	1930
	21st to end	Day	15% 5% 2 4 3 4 3 4 6% 6% 51%	1552
December	1st to 10th	Day	17% 7% 2 5% 3 4 5% 4 5% 7% 40%	1520
	11th to 20th	Day	17% 5% 1 4 2 2 3 3 3 6% 55%	1910
	21st to end	Day	18% 5% 2 4 4 3 5% 4 6% 8% 42%	3032
January	1st to 10th	Night	14% 7% 2 6% 3 4 4 3 4 6% 48%	4109
	11th to 20th	Night	15% 7% 3 6% 4 3 3 3 4 5% 48%	4120
	21st to end	Night	20% 8% 3 6% 4 3 3 3 4 4 43%	4532
February	1st to 10th	Night	16% 6% 2 5% 4 4 4 3 6% 6% 46%	2470
	11th to 20th	Night	19% 7% 3 5% 3 3 4 4 4 6% 43%	2394
	21st to end	Night	15% 8% 1 5% 4 4 3 3 5% 5% 45%	1770
March	1st to 10th	Night	21% 8% 2 7% 4 5% 4 4 4 5% 36%	3418
	11th to 20th	Night	13% 5% 2 5% 4 3 3 3 4 6% 53%	3480
	21st to end	Night	17% 5% 2 5% 3 3 3 3 4 6% 49%	3817
April	1st to 10th	Night	13% 7% 2 6% 4 4 4 3 5% 6% 47%	1952
	11th to 20th	Night	11% 5% 2 4 4 4 4 3 5% 7% 51%	1875
	21st to end	Night	13% 5% 2 5% 5% 4 5% 4 5% 6% 47%	1900
May	1st to 10th	Night	14% 7% 3 8% 5% 4 5% 4 5% 7% 37%	2852
	11th to 20th	Night	22% 8% 3 6% 4 4 3 3 5% 6% 36%	2812
	21st to end	Night	9% 4 2 6% 4 3 4 4 6% 10% 47%	3079
June	1st to 10th	Night	10% 4 2 5% 4 5% 4 4 7% 11% 44%	1563
	11th to 20th	Night	9% 5% 2 5% 6% 4 5% 5% 7% 12% 41%	1520
	21st to end	Night	7% 4 2 5% 5% 6% 6% 5% 7% 11% 41%	1657
July	1st to 10th	Night	6% 5% 3 7% 6% 6% 6% 6% 8% 10% 36%	2840
	11th to 20th	Night	10% 7% 3 7% 6% 5% 6% 6% 8% 10% 33%	2840
	21st to end	Night	14% 8% 4 9% 7% 5% 6% 4 7% 8% 28%	3087
August	1st to 10th	Night	17% 7% 3 8% 6% 5% 5% 5% 7% 10% 28%	2825
	11th to 20th	Night	7% 5% 3 7% 5% 5% 5% 5% 7% 11% 41%	2871
	21st to end	Night	8% 5% 2 5% 6% 5% 4 4 7% 10% 45%	3476
September	1st to 10th	Night	11% 7% 3 5% 4 4 4 3 6% 7% 46%	1900
	11th to 20th	Night	14% 7% 3 7% 4 4 4 4 6% 6% 43%	1998
	21st to end	Night	22% 8% 2 6% 4 4 4 4 4 5% 38%	2143
October	1st to 10th	Night	15% 6% 1 6% 5% 3 4 3 5% 6% 46%	2280
	11th to 20th	Night	13% 6% 2 5% 4 4 3 2 3 6% 53%	2280
	21st to end	Night	12% 4 1 4 3 3 4 3 4 6% 54%	2508
November	1st to 10th	Night	12% 7% 2 5% 4 3 3 3 5% 5% 52%	2341
	11th to 20th	Night	13% 6% 2 4 3 3 3 4 5% 5% 50%	2460
	21st to end	Night	13% 4 2 5% 3 3 3 3 5% 6% 52%	2723
December	1st to 10th	Night	17% 8% 2 6% 5% 4 4 4 4 5% 42%	2660
	11th to 20th	Night	16% 6% 2 5% 4 3 3 3 4 5% 48%	3285
	21st to end	Night	17% 7% 2 5% 3 3 3 4 5% 7% 42%	4617

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	36% 3 6% 28% 21% 5%	2837
	11th to 20th	Day	36% 4 6% 21% 27% 6%	2840
	21st to end	Day	47% 4 7% 20% 17% 4	3124
February	1st to 10th	Day	40% 5% 11% 22% 18% 4	1710
	11th to 20th	Day	42% 4 6% 21% 20% 6%	1680
	21st to end	Day	45% 6% 11% 15% 17% 6%	1679
March	1st to 10th	Day	47% 5% 8% 20% 13% 7%	3435
	11th to 20th	Day	30% 6% 9% 21% 23% 11%	3480
	21st to end	Day	44% 5% 9% 20% 19% 3	3815
April	1st to 10th	Day	29% 5% 12% 24% 22% 9%	2226
	11th to 20th	Day	35% 5% 11% 22% 21% 7%	2254
	21st to end	Day	39% 6% 12% 23% 16% 5%	2280
May	1st to 10th	Day	44% 9% 14% 21% 11% 2	4110
	11th to 20th	Day	47% 8% 10% 24% 9% 2	4085
	21st to end	Day	30% 9% 16% 23% 19% 3	4489
June	1st to 10th	Day	33% 9% 15% 26% 15% 1	2608
	11th to 20th	Day	32% 9% 17% 24% 15% 2	2660
	21st to end	Day	33% 11% 16% 23% 15% 2	2511
July	1st to 10th	Day	36% 12% 18% 19% 11% 4	4055
	11th to 20th	Day	38% 10% 23% 22% 7% 1	4051
	21st to end	Day	48% 10% 13% 18% 12%	4324
August	1st to 10th	Day	48% 8% 17% 21% 5%	4091
	11th to 20th	Day	38% 9% 21% 21% 10% 1	3965
	21st to end	Day	29% 6% 16% 31% 16% 2	4180
September	1st to 10th	Day	35% 9% 14% 17% 21% 4	2280
	11th to 20th	Day	40% 7% 10% 21% 20% 3	2179
	21st to end	Day	46% 6% 8% 19% 17% 3	2035
October	1st to 10th	Day	34% 4 7% 19% 28% 7%	3160
	11th to 20th	Day	21% 3 5% 22% 30% 18%	3140
	21st to end	Day	24% 3 7% 27% 26% 12%	3428
November	1st to 10th	Day	33% 5% 7% 24% 26% 6%	1957
	11th to 20th	Day	35% 4 10% 21% 23% 8%	1930
	21st to end	Day	33% 5% 8% 24% 25% 5%	1552
December	1st to 10th	Day	42% 6% 10% 22% 17% 3	1520
	11th to 20th	Day	33% 4 8% 25% 22% 8%	1906
	21st to end	Day	38% 6% 12% 24% 18% 2	3032
January	1st to 10th	Night	37% 4 7% 22% 25% 6%	4109
	11th to 20th	Night	40% 4 7% 19% 26% 5%	4120
	21st to end	Night	45% 4 5% 21% 18% 6%	4532
February	1st to 10th	Night	39% 4 10% 23% 19% 4	2470
	11th to 20th	Night	42% 4 7% 20% 20% 6%	2396
	21st to end	Night	41% 5% 7% 22% 18% 7%	1770
March	1st to 10th	Night	50% 6% 9% 16% 16% 4	3418
	11th to 20th	Night	33% 4 6% 17% 26% 13%	3480
	21st to end	Night	37% 5% 8% 25% 20% 5%	3817
April	1st to 10th	Night	38% 6% 10% 17% 24% 7%	1952
	11th to 20th	Night	32% 5% 10% 24% 22% 7%	1875
	21st to end	Night	36% 5% 11% 24% 19% 5%	1900
May	1st to 10th	Night	44% 8% 13% 21% 11% 2	2879
	11th to 20th	Night	48% 7% 10% 20% 13% 2	2813
	21st to end	Night	30% 9% 15% 26% 17% 3	3087
June	1st to 10th	Night	34% 9% 15% 25% 17% 1	1563
	11th to 20th	Night	34% 9% 17% 21% 16% 2	1520
	21st to end	Night	35% 10% 13% 22% 16% 3	1657
July	1st to 10th	Night	39% 13% 15% 18% 12% 2	2795
	11th to 20th	Night	42% 11% 21% 18% 5% 2	2786
	21st to end	Night	51% 9% 13% 18% 9%	2988
August	1st to 10th	Night	49% 9% 18% 17% 7%	2814
	11th to 20th	Night	34% 9% 20% 26% 10% 1	2898
	21st to end	Night	34% 7% 11% 29% 18% 2	3476
September	1st to 10th	Night	36% 8% 12% 21% 18% 6%	1900
	11th to 20th	Night	40% 8% 9% 19% 21% 3	1998
	21st to end	Night	49% 6% 9% 16% 16% 4	2143
October	1st to 10th	Night	39% 5% 9% 18% 24% 5%	3800
	11th to 20th	Night	25% 3 6% 22% 28% 15%	3779
	21st to end	Night	23% 3 6% 29% 25% 14%	4120
November	1st to 10th	Night	35% 4 8% 21% 25% 7%	2341
	11th to 20th	Night	34% 5% 8% 17% 24% 11%	2460
	21st to end	Night	33% 4 8% 22% 25% 7%	2723
December	1st to 10th	Night	44% 5% 8% 21% 18% 4	2660
	11th to 20th	Night	38% 4 8% 21% 22% 7%	3288
	21st to end	Night	40% 4 8% 25% 20% 2	4617

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	27% 26% 30% 13% 5%	270
	11th to 20th	Day	27% 24% 37% 10% 1	270
	21st to end	Day	24% 22% 38% 14% 3	297
February	1st to 10th	Day	20% 22% 40% 16% 3	270
	11th to 20th	Day	37% 24% 29% 8% 3	278
	21st to end	Day	27% 21% 32% 17% 2	382
March	1st to 10th	Day	23% 19% 33% 18% 6%	460
	11th to 20th	Day	21% 23% 35% 15% 5% 1	460
	21st to end	Day	22% 17% 36% 19% 5% 1	506
April	1st to 10th	Day	17% 21% 33% 20% 8% 1	460
	11th to 20th	Day	17% 15% 33% 22% 10% 4	452
	21st to end	Day	19% 14% 33% 23% 10% 2	460
May	1st to 10th	Day	18% 15% 33% 23% 10% 2	463
	11th to 20th	Day	16% 11% 24% 29% 16% 3	487
	21st to end	Day	18% 4 23% 27% 21% 7%	529
June	1st to 10th	Day	10% 6% 27% 30% 21% 7%	490
	11th to 20th	Day	10% 5% 22% 31% 24% 8%	490
	21st to end	Day	10% 4 21% 34% 24% 7%	490
July	1st to 10th	Day	9% 2 14% 33% 31% 11%	485
	11th to 20th	Day	5% 2 13% 33% 34% 12%	484
	21st to end	Day	9% 2 17% 36% 26% 10%	532
August	1st to 10th	Day	13% 4 18% 28% 26% 12%	486
	11th to 20th	Day	11% 4 14% 31% 28% 11%	479
	21st to end	Day	9% 2 12% 30% 30% 17%	539
September	1st to 10th	Day	12% 5% 15% 25% 26% 16%	490
	11th to 20th	Day	16% 6% 14% 29% 23% 12%	490
	21st to end	Day	27% 8% 20% 26% 14% 5%	490
October	1st to 10th	Day	18% 7% 22% 24% 22% 7%	490
	11th to 20th	Day	14% 10% 25% 27% 19% 5%	490
	21st to end	Day	14% 11% 27% 31% 13% 4	539
November	1st to 10th	Day	17% 9% 29% 27% 14% 4	495
	11th to 20th	Day	18% 14% 29% 25% 12% 1	450
	21st to end	Day	19% 19% 23% 27% 10% 2	188
December	1st to 10th	Day	24% 18% 34% 16% 5% 2	180
	11th to 20th	Day	24% 15% 29% 24% 6% 1	180
	21st to end	Day	24% 16% 38% 13% 8% 2	272
January	1st to 10th	Night	20% 19% 35% 22% 4	760
	11th to 20th	Night	20% 17% 33% 26% 4	760
	21st to end	Night	19% 16% 36% 25% 3	836
February	1st to 10th	Night	19% 15% 36% 25% 4	760
	11th to 20th	Night	26% 19% 37% 17% 1	743
	21st to end	Night	20% 16% 39% 23% 3	628
March	1st to 10th	Night	18% 16% 34% 27% 4	760
	11th to 20th	Night	20% 17% 34% 23% 7%	760
	21st to end	Night	19% 13% 42% 21% 5%	836
April	1st to 10th	Night	17% 18% 36% 23% 6%	760
	11th to 20th	Night	14% 14% 35% 26% 11%	751
	21st to end	Night	15% 8% 36% 33% 8%	760
May	1st to 10th	Night	14% 11% 32% 31% 11%	596
	11th to 20th	Night	20% 6% 25% 31% 18%	561
	21st to end	Night	14% 3 16% 35% 29% 3	617
June	1st to 10th	Night	10% 3 20% 42% 24% 1	423
	11th to 20th	Night	12% 2 17% 41% 26% 3	380
	21st to end	Night	8% 3 15% 45% 28% 2	517
July	1st to 10th	Night	9% 1 14% 36% 35% 5%	555
	11th to 20th	Night	6% 2 10% 38% 39% 6%	552
	21st to end	Night	7% 2 16% 40% 31% 3	624
August	1st to 10th	Night	13% 2 10% 40% 29% 5%	567
	11th to 20th	Night	11% 3 11% 37% 34% 4	611
	21st to end	Night	10% 1 12% 33% 37% 6%	836
September	1st to 10th	Night	14% 2 13% 33% 33% 6%	760
	11th to 20th	Night	16% 4 15% 29% 32% 4	760
	21st to end	Night	26% 4 17% 33% 20% 1	760
October	1st to 10th	Night	18% 4 18% 30% 25% 5%	760
	11th to 20th	Night	16% 9% 25% 30% 19% 1	760
	21st to end	Night	14% 9% 25% 33% 17% 2	836
November	1st to 10th	Night	16% 8% 26% 33% 16% 2	780
	11th to 20th	Night	16% 11% 29% 33% 11%	800
	21st to end	Night	15% 11% 30% 32% 10% 1	779
December	1st to 10th	Night	21% 13% 33% 24% 8%	760
	11th to 20th	Night	19% 10% 35% 31% 5%	760
	21st to end	Night	23% 14% 26% 31% 5%	836

Page generated at 2024-11-22 08:02:27. Version ac07

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