Staunton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Staunton clear sky chart from 2005-11-05 to 2024-10-14.

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 6% 5% 5% 5% 4 6% 8% 41%	100708
	Night	13% 6% 2 6% 4 4 4 4 6% 7% 44%	97780
Transparency	Day	40% 8% 13% 22% 14% 3	100521
	Night	38% 7% 12% 23% 16% 3	97642
Seeing	Day	18% 14% 24% 24% 15% 5%	14922
	Night	16% 11% 25% 31% 15% 2	24743

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% 7% 2 6% 5% 5% 4 3 5% 5% 44%	2836
	11th to 20th	Day	13% 9% 3 8% 6% 5% 5% 4 5% 5% 40%	2840
	21st to end	Day	13% 10% 3 8% 5% 4 4 4 4 6% 40%	3124
February	1st to 10th	Day	11% 7% 2 8% 5% 4 6% 4 5% 7% 42%	1710
	11th to 20th	Day	14% 8% 2 7% 4 4 4 4 6% 7% 41%	1663
	21st to end	Day	14% 8% 3 6% 4 5% 5% 3 5% 6% 41%	1638
March	1st to 10th	Day	17% 10% 3 7% 4 4 3 3 5% 6% 37%	3435
	11th to 20th	Day	9% 5% 2 5% 4 4 4 4 6% 7% 51%	3480
	21st to end	Day	14% 9% 3 7% 5% 5% 4 4 5% 6% 38%	3815
April	1st to 10th	Day	8% 7% 2 6% 4 5% 5% 4 6% 7% 47%	2217
	11th to 20th	Day	12% 6% 2 5% 4 4 4 4 6% 8% 46%	2254
	21st to end	Day	14% 7% 2 6% 5% 4 4 3 5% 6% 42%	2356
May	1st to 10th	Day	15% 6% 3 8% 6% 6% 6% 5% 8% 8% 31%	4082
	11th to 20th	Day	20% 8% 3 7% 4 5% 4 4 5% 7% 34%	4081
	21st to end	Day	9% 5% 2 6% 4 5% 5% 4 7% 10% 43%	4592
June	1st to 10th	Day	11% 4 2 5% 5% 6% 5% 5% 6% 10% 42%	2660
	11th to 20th	Day	9% 6% 2 6% 6% 5% 6% 5% 7% 10% 38%	2660
	21st to end	Day	7% 4 2 5% 6% 4 5% 5% 7% 11% 43%	2652
July	1st to 10th	Day	7% 4 2 5% 5% 5% 6% 5% 9% 10% 42%	4120
	11th to 20th	Day	9% 4 2 6% 5% 5% 6% 5% 8% 12% 37%	4120
	21st to end	Day	12% 7% 3 9% 6% 7% 6% 5% 7% 9% 30%	4466
August	1st to 10th	Day	12% 5% 2 7% 6% 6% 6% 5% 9% 10% 34%	4104
	11th to 20th	Day	9% 4 2 6% 6% 5% 6% 5% 7% 10% 39%	4019
	21st to end	Day	9% 3 2 5% 4 4 5% 4 7% 9% 47%	4180
September	1st to 10th	Day	12% 6% 2 6% 4 5% 4 3 5% 5% 48%	2280
	11th to 20th	Day	12% 8% 2 6% 4 5% 4 3 5% 7% 44%	2153
	21st to end	Day	22% 6% 2 5% 4 3 4 4 6% 6% 37%	2051
October	1st to 10th	Day	15% 5% 2 6% 3 4 4 3 4 6% 48%	1900
	11th to 20th	Day	14% 5% 2 5% 3 3 3 3 5% 6% 50%	1830
	21st to end	Day	11% 6% 2 6% 4 3 4 4 4 6% 51%	1980
November	1st to 10th	Day	11% 5% 2 4 4 3 3 3 4 6% 55%	1857
	11th to 20th	Day	11% 6% 2 5% 3 4 4 4 5% 5% 50%	1699
	21st to end	Day	12% 5% 2 5% 4 3 3 4 5% 7% 50%	1520
December	1st to 10th	Day	13% 7% 3 6% 5% 5% 5% 4 5% 6% 40%	1520
	11th to 20th	Day	13% 5% 1 5% 3 3 3 3 5% 7% 53%	1910
	21st to end	Day	16% 7% 2 6% 5% 4 5% 5% 6% 8% 35%	2904
January	1st to 10th	Night	10% 7% 2 6% 4 4 4 4 5% 7% 47%	4109
	11th to 20th	Night	13% 8% 2 5% 3 4 4 3 4 6% 47%	4120
	21st to end	Night	14% 10% 3 6% 4 4 4 3 4 6% 42%	4532
February	1st to 10th	Night	10% 7% 3 5% 4 4 4 4 6% 7% 44%	2470
	11th to 20th	Night	17% 8% 2 6% 3 4 4 3 5% 6% 41%	2403
	21st to end	Night	12% 8% 2 5% 5% 3 5% 4 6% 7% 42%	1809
March	1st to 10th	Night	19% 8% 3 6% 4 4 4 4 5% 6% 36%	3418
	11th to 20th	Night	10% 6% 2 5% 4 3 4 4 6% 7% 50%	3480
	21st to end	Night	14% 7% 2 5% 4 3 3 3 5% 6% 47%	3817
April	1st to 10th	Night	11% 6% 3 6% 5% 4 4 4 5% 8% 43%	1962
	11th to 20th	Night	10% 5% 2 5% 4 4 4 4 6% 8% 48%	1875
	21st to end	Night	15% 4 2 5% 4 4 5% 3 5% 6% 45%	1838
May	1st to 10th	Night	16% 7% 3 6% 5% 5% 4 5% 6% 8% 35%	2813
	11th to 20th	Night	22% 8% 3 5% 4 3 4 3 6% 6% 35%	2812
	21st to end	Night	9% 4 2 6% 4 4 5% 4 7% 10% 44%	2958
June	1st to 10th	Night	10% 5% 2 6% 4 4 4 3 7% 11% 45%	1520
	11th to 20th	Night	8% 4 2 7% 4 4 5% 5% 7% 9% 45%	1520
	21st to end	Night	8% 4 2 3 5% 4 5% 4 7% 11% 48%	1522
July	1st to 10th	Night	6% 4 2 5% 4 4 6% 5% 8% 10% 47%	2840
	11th to 20th	Night	8% 5% 2 6% 5% 6% 6% 5% 8% 10% 38%	2840
	21st to end	Night	11% 7% 3 8% 6% 6% 6% 4 7% 8% 34%	3087
August	1st to 10th	Night	14% 5% 2 6% 4 5% 5% 4 8% 10% 36%	2825
	11th to 20th	Night	9% 5% 3 8% 5% 5% 5% 5% 8% 8% 39%	2785
	21st to end	Night	10% 5% 2 6% 4 4 4 4 6% 9% 46%	3466
September	1st to 10th	Night	12% 5% 2 6% 4 3 4 4 5% 7% 49%	1900
	11th to 20th	Night	13% 6% 2 5% 4 4 5% 3 5% 7% 46%	2023
	21st to end	Night	21% 7% 2 5% 4 3 4 3 5% 5% 41%	2128
October	1st to 10th	Night	17% 5% 2 5% 4 4 4 2 5% 6% 47%	2280
	11th to 20th	Night	13% 5% 2 5% 3 4 4 3 4 6% 51%	2203
	21st to end	Night	12% 4 2 6% 4 3 3 3 4 7% 51%	2376
November	1st to 10th	Night	10% 7% 2 5% 4 3 3 3 4 5% 53%	2221
	11th to 20th	Night	11% 6% 2 5% 4 4 3 3 5% 6% 51%	2476
	21st to end	Night	11% 6% 2 5% 4 4 4 3 5% 6% 50%	2660
December	1st to 10th	Night	12% 8% 2 7% 4 5% 5% 4 5% 6% 43%	2660
	11th to 20th	Night	13% 7% 2 5% 5% 4 4 3 5% 6% 46%	3285
	21st to end	Night	14% 6% 3 6% 4 4 5% 4 6% 8% 39%	4747

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	39% 4 10% 25% 16% 6%	2837
	11th to 20th	Day	45% 4 9% 18% 18% 6%	2840
	21st to end	Day	46% 5% 8% 22% 17% 3	3124
February	1st to 10th	Day	43% 6% 10% 22% 16% 3	1710
	11th to 20th	Day	41% 7% 10% 20% 17% 4	1672
	21st to end	Day	44% 7% 11% 16% 17% 5%	1638
March	1st to 10th	Day	48% 6% 9% 19% 13% 5%	3435
	11th to 20th	Day	31% 6% 9% 27% 20% 7%	3480
	21st to end	Day	46% 8% 9% 19% 14% 3	3815
April	1st to 10th	Day	35% 7% 11% 21% 18% 7%	2217
	11th to 20th	Day	36% 7% 12% 21% 20% 5%	2254
	21st to end	Day	43% 7% 12% 22% 13% 4	2356
May	1st to 10th	Day	47% 10% 13% 19% 10% 1	4120
	11th to 20th	Day	48% 8% 12% 21% 9% 1	4085
	21st to end	Day	32% 12% 17% 20% 17% 3	4606
June	1st to 10th	Day	37% 10% 15% 24% 13% 1	2660
	11th to 20th	Day	38% 12% 15% 20% 13% 1	2660
	21st to end	Day	33% 12% 17% 25% 13% 1	2652
July	1st to 10th	Day	33% 12% 20% 20% 9% 5%	4055
	11th to 20th	Day	36% 11% 19% 25% 8% 1	4051
	21st to end	Day	48% 10% 12% 19% 10% 1	4324
August	1st to 10th	Day	42% 10% 19% 22% 6%	4091
	11th to 20th	Day	36% 11% 14% 27% 11% 1	4058
	21st to end	Day	31% 10% 19% 26% 12% 1	4180
September	1st to 10th	Day	38% 8% 14% 17% 19% 4	2280
	11th to 20th	Day	40% 7% 9% 24% 18% 3	2153
	21st to end	Day	46% 7% 10% 18% 16% 2	2051
October	1st to 10th	Day	37% 6% 10% 24% 17% 5%	1900
	11th to 20th	Day	35% 5% 11% 24% 21% 4	1831
	21st to end	Day	35% 5% 9% 26% 20% 6%	1980
November	1st to 10th	Day	32% 4 9% 24% 26% 5%	1857
	11th to 20th	Day	35% 6% 10% 20% 22% 8%	1699
	21st to end	Day	34% 5% 11% 24% 22% 3	1520
December	1st to 10th	Day	43% 7% 12% 20% 15% 3	1520
	11th to 20th	Day	33% 5% 9% 27% 19% 7%	1906
	21st to end	Day	43% 7% 13% 23% 13% 2	2904
January	1st to 10th	Night	35% 5% 11% 24% 22% 4	4109
	11th to 20th	Night	38% 5% 10% 22% 20% 5%	4120
	21st to end	Night	44% 5% 7% 23% 17% 4	4532
February	1st to 10th	Night	38% 8% 11% 24% 17% 2	2470
	11th to 20th	Night	43% 5% 8% 20% 17% 6%	2405
	21st to end	Night	40% 7% 13% 22% 13% 6%	1809
March	1st to 10th	Night	47% 6% 10% 20% 13% 3	3418
	11th to 20th	Night	31% 5% 8% 24% 26% 5%	3480
	21st to end	Night	38% 6% 11% 22% 19% 4	3817
April	1st to 10th	Night	38% 8% 11% 19% 19% 5%	1962
	11th to 20th	Night	32% 8% 15% 20% 20% 5%	1875
	21st to end	Night	38% 7% 12% 25% 15% 3	1838
May	1st to 10th	Night	45% 10% 13% 19% 11% 2	2840
	11th to 20th	Night	48% 8% 12% 23% 8% 1	2813
	21st to end	Night	32% 12% 18% 25% 11% 3	2965
June	1st to 10th	Night	33% 10% 14% 28% 13% 1	1520
	11th to 20th	Night	34% 11% 18% 24% 12% 2	1520
	21st to end	Night	31% 11% 18% 21% 17% 2	1522
July	1st to 10th	Night	31% 12% 22% 19% 13% 3	2795
	11th to 20th	Night	37% 12% 19% 23% 9% 1	2786
	21st to end	Night	45% 12% 16% 20% 8%	2988
August	1st to 10th	Night	41% 10% 18% 24% 6% 1	2814
	11th to 20th	Night	39% 11% 15% 24% 11%	2812
	21st to end	Night	32% 9% 17% 31% 8% 2	3466
September	1st to 10th	Night	35% 9% 14% 20% 17% 5%	1900
	11th to 20th	Night	37% 7% 11% 25% 18% 3	2023
	21st to end	Night	45% 7% 10% 19% 16% 3	2128
October	1st to 10th	Night	39% 6% 12% 23% 17% 3	2280
	11th to 20th	Night	34% 5% 10% 25% 22% 4	2207
	21st to end	Night	33% 5% 10% 23% 25% 5%	2376
November	1st to 10th	Night	34% 5% 9% 21% 24% 7%	2221
	11th to 20th	Night	34% 5% 8% 22% 24% 6%	2476
	21st to end	Night	36% 5% 10% 24% 21% 5%	2660
December	1st to 10th	Night	42% 6% 10% 23% 15% 4	2660
	11th to 20th	Night	39% 5% 9% 22% 20% 6%	3288
	21st to end	Night	40% 6% 12% 22% 18% 2	4747

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	23% 34% 24% 14% 3	270
	11th to 20th	Day	30% 31% 25% 12% 1	270
	21st to end	Day	26% 28% 32% 13% 1	297
February	1st to 10th	Day	23% 31% 31% 13% 1	270
	11th to 20th	Day	39% 27% 27% 7%	270
	21st to end	Day	31% 23% 26% 17% 3	341
March	1st to 10th	Day	21% 27% 28% 18% 5%	460
	11th to 20th	Day	24% 25% 28% 17% 4 2	460
	21st to end	Day	22% 21% 31% 21% 5% 1	506
April	1st to 10th	Day	22% 25% 26% 18% 9%	460
	11th to 20th	Day	20% 17% 27% 21% 12% 3	452
	21st to end	Day	22% 18% 30% 19% 9% 2	460
May	1st to 10th	Day	19% 21% 28% 20% 8% 4	463
	11th to 20th	Day	22% 12% 26% 22% 14% 4	487
	21st to end	Day	18% 8% 22% 26% 19% 7%	529
June	1st to 10th	Day	12% 8% 28% 27% 18% 7%	490
	11th to 20th	Day	11% 8% 24% 29% 17% 10%	490
	21st to end	Day	8% 6% 29% 32% 18% 6%	490
July	1st to 10th	Day	11% 4 17% 30% 28% 10%	485
	11th to 20th	Day	5% 2 19% 36% 27% 11%	484
	21st to end	Day	10% 4 20% 31% 25% 10%	532
August	1st to 10th	Day	12% 5% 19% 27% 26% 12%	486
	11th to 20th	Day	11% 4 20% 26% 26% 12%	479
	21st to end	Day	10% 3 13% 34% 23% 17%	539
September	1st to 10th	Day	13% 5% 17% 26% 23% 16%	490
	11th to 20th	Day	14% 5% 15% 28% 27% 10%	490
	21st to end	Day	27% 10% 19% 23% 17% 4	490
October	1st to 10th	Day	19% 6% 22% 30% 19% 4	490
	11th to 20th	Day	16% 14% 24% 25% 18% 3	462
	21st to end	Day	17% 15% 32% 23% 10% 3	495
November	1st to 10th	Day	16% 13% 27% 28% 12% 3	455
	11th to 20th	Day	21% 15% 28% 24% 11% 1	304
	21st to end	Day	21% 18% 33% 21% 7% 1	180
December	1st to 10th	Day	23% 22% 35% 14% 5% 1	180
	11th to 20th	Day	23% 22% 26% 21% 8% 1	180
	21st to end	Day	20% 25% 32% 16% 6%	236
January	1st to 10th	Night	18% 21% 35% 22% 3	760
	11th to 20th	Night	19% 20% 30% 28% 3	760
	21st to end	Night	17% 20% 37% 24% 2	836
February	1st to 10th	Night	16% 20% 32% 29% 3	760
	11th to 20th	Night	24% 22% 34% 19% 1	743
	21st to end	Night	21% 18% 37% 22% 3	628
March	1st to 10th	Night	17% 20% 32% 27% 4	760
	11th to 20th	Night	23% 20% 29% 21% 6% 1	760
	21st to end	Night	20% 15% 32% 27% 5% 1	836
April	1st to 10th	Night	16% 20% 34% 24% 5%	760
	11th to 20th	Night	14% 16% 31% 28% 12% 1	751
	21st to end	Night	18% 10% 31% 32% 8% 1	698
May	1st to 10th	Night	18% 9% 26% 31% 14% 1	570
	11th to 20th	Night	19% 7% 23% 36% 15% 1	561
	21st to end	Night	15% 2 17% 39% 25% 2	547
June	1st to 10th	Night	10% 1 19% 48% 21% 2	380
	11th to 20th	Night	9% 3 17% 44% 25% 2	380
	21st to end	Night	7% 4 19% 46% 22% 2	382
July	1st to 10th	Night	10% 3 12% 35% 35% 5%	555
	11th to 20th	Night	5% 1 8% 38% 41% 7%	552
	21st to end	Night	7% 3 13% 40% 31% 6%	624
August	1st to 10th	Night	11% 2 10% 38% 35% 4	567
	11th to 20th	Night	12% 3 11% 39% 32% 4	564
	21st to end	Night	13% 2 11% 34% 36% 4	826
September	1st to 10th	Night	14% 3 10% 36% 32% 5%	760
	11th to 20th	Night	15% 3 13% 33% 31% 5%	760
	21st to end	Night	24% 5% 18% 31% 19% 2	760
October	1st to 10th	Night	18% 6% 17% 33% 22% 4	760
	11th to 20th	Night	15% 11% 25% 32% 15% 1	735
	21st to end	Night	16% 11% 27% 33% 12% 1	792
November	1st to 10th	Night	15% 9% 26% 34% 13% 2	740
	11th to 20th	Night	15% 14% 29% 32% 9% 1	760
	21st to end	Night	15% 16% 27% 32% 9% 1	760
December	1st to 10th	Night	19% 15% 32% 27% 6%	760
	11th to 20th	Night	15% 14% 32% 33% 6%	760
	21st to end	Night	17% 14% 31% 34% 4	836

Page generated at 2024-10-11 10:49:59. Version ac07

Copyright © 2024 Attilla Danko.