Uniontown
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Uniontown clear sky chart from 2005-11-06 to 2024-11-11.

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	17% 11% 4 8% 5% 4 4 4 5% 7% 31%	101126
	Night	18% 13% 4 8% 4 4 4 3 5% 6% 31%	97943
Transparency	Day	50% 7% 11% 20% 10% 1	104776
	Night	51% 7% 10% 19% 11% 2	102433
Seeing	Day	25% 16% 25% 20% 11% 4	14814
	Night	24% 14% 24% 26% 11% 1	24516

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	19% 21% 8% 12% 5% 4 3 2 3 5% 18%	2836
	11th to 20th	Day	13% 23% 10% 16% 8% 4 3 1 2 3 16%	2840
	21st to end	Day	23% 20% 9% 11% 7% 4 3 2 3 4 14%	3124
February	1st to 10th	Day	20% 19% 5% 10% 7% 5% 3 4 4 5% 21%	1710
	11th to 20th	Day	17% 17% 7% 12% 4 4 4 3 4 5% 22%	1663
	21st to end	Day	22% 17% 5% 9% 4 3 4 3 5% 4 25%	1588
March	1st to 10th	Day	19% 16% 5% 8% 4 4 4 2 4 6% 29%	3435
	11th to 20th	Day	16% 12% 5% 9% 4 4 4 3 4 6% 32%	3480
	21st to end	Day	21% 12% 3 8% 5% 4 4 3 4 5% 30%	3815
April	1st to 10th	Day	17% 15% 4 7% 4 5% 5% 4 6% 7% 29%	2199
	11th to 20th	Day	17% 12% 2 6% 5% 4 5% 4 4 7% 33%	2254
	21st to end	Day	23% 10% 3 6% 4 4 4 3 5% 7% 31%	2460
May	1st to 10th	Day	24% 10% 3 8% 5% 4 5% 3 5% 6% 27%	4082
	11th to 20th	Day	20% 9% 3 8% 5% 4 5% 4 6% 7% 29%	4081
	21st to end	Day	14% 7% 2 7% 5% 5% 5% 5% 7% 9% 35%	4715
June	1st to 10th	Day	16% 6% 2 7% 5% 5% 5% 5% 6% 9% 34%	2660
	11th to 20th	Day	14% 7% 3 8% 6% 5% 5% 4 7% 9% 34%	2660
	21st to end	Day	16% 6% 2 7% 5% 5% 5% 5% 7% 9% 34%	2660
July	1st to 10th	Day	11% 6% 3 6% 5% 6% 5% 5% 7% 7% 39%	4264
	11th to 20th	Day	12% 6% 3 7% 4 5% 5% 4 7% 9% 38%	4120
	21st to end	Day	15% 9% 3 7% 5% 4 5% 4 6% 8% 33%	4466
August	1st to 10th	Day	14% 9% 3 8% 5% 5% 6% 5% 7% 9% 30%	4104
	11th to 20th	Day	15% 6% 2 6% 5% 4 5% 5% 7% 8% 37%	4044
	21st to end	Day	9% 4 2 5% 5% 5% 5% 5% 7% 9% 43%	4262
September	1st to 10th	Day	16% 6% 2 5% 4 4 4 3 5% 7% 44%	2280
	11th to 20th	Day	14% 6% 2 5% 4 3 4 4 5% 9% 44%	2116
	21st to end	Day	20% 9% 3 7% 5% 4 4 3 5% 7% 33%	2076
October	1st to 10th	Day	17% 7% 2 7% 4 4 4 4 5% 6% 40%	1900
	11th to 20th	Day	20% 10% 2 7% 3 5% 3 3 4 6% 36%	1900
	21st to end	Day	25% 11% 2 6% 3 4 3 3 3 5% 36%	2090
November	1st to 10th	Day	13% 11% 2 6% 4 5% 3 3 4 5% 43%	1922
	11th to 20th	Day	16% 15% 5% 8% 4 4 4 3 5% 5% 32%	1587
	21st to end	Day	19% 19% 5% 7% 3 4 3 2 4 6% 28%	1520
December	1st to 10th	Day	21% 20% 8% 11% 5% 3 3 4 4 4 18%	1520
	11th to 20th	Day	20% 20% 8% 11% 3 2 3 3 4 5% 22%	1910
	21st to end	Day	21% 22% 6% 12% 5% 4 3 2 4 5% 16%	2783
January	1st to 10th	Night	17% 23% 8% 13% 4 4 3 3 3 4 18%	4109
	11th to 20th	Night	17% 20% 9% 14% 5% 6% 4 3 3 4 15%	4120
	21st to end	Night	26% 19% 9% 11% 6% 3 2 2 2 3 17%	4532
February	1st to 10th	Night	20% 16% 4 11% 5% 3 3 3 4 4 26%	2470
	11th to 20th	Night	19% 17% 5% 13% 4 5% 4 2 4 5% 22%	2403
	21st to end	Night	21% 16% 5% 10% 4 4 4 3 4 6% 23%	1861
March	1st to 10th	Night	22% 14% 4 7% 4 3 3 3 4 6% 30%	3418
	11th to 20th	Night	17% 17% 5% 8% 4 3 3 3 4 5% 31%	3480
	21st to end	Night	18% 12% 3 7% 4 4 4 3 4 5% 37%	3817
April	1st to 10th	Night	19% 16% 3 7% 5% 4 4 3 3 5% 32%	1979
	11th to 20th	Night	18% 9% 3 6% 4 3 4 4 5% 7% 36%	1875
	21st to end	Night	18% 9% 3 7% 4 4 3 3 5% 7% 37%	1734
May	1st to 10th	Night	26% 11% 4 8% 4 4 4 3 5% 5% 25%	2813
	11th to 20th	Night	20% 10% 3 7% 5% 4 4 3 5% 6% 34%	2812
	21st to end	Night	14% 10% 3 7% 4 4 5% 4 6% 8% 35%	2836
June	1st to 10th	Night	11% 7% 2 8% 5% 4 4 3 5% 8% 42%	1520
	11th to 20th	Night	13% 7% 2 7% 4 4 4 4 8% 11% 37%	1520
	21st to end	Night	12% 7% 3 5% 4 4 5% 5% 7% 9% 39%	1520
July	1st to 10th	Night	12% 9% 3 7% 5% 4 5% 3 6% 8% 38%	2677
	11th to 20th	Night	13% 7% 2 8% 5% 4 5% 4 6% 8% 38%	2840
	21st to end	Night	14% 9% 3 7% 4 4 5% 4 6% 6% 37%	3087
August	1st to 10th	Night	14% 8% 3 9% 5% 5% 5% 4 6% 10% 32%	2825
	11th to 20th	Night	17% 7% 3 7% 4 4 4 3 5% 7% 39%	2785
	21st to end	Night	8% 5% 2 6% 5% 5% 5% 4 7% 9% 44%	3348
September	1st to 10th	Night	14% 6% 2 6% 4 5% 4 3 6% 6% 45%	1900
	11th to 20th	Night	13% 5% 1 4 3 3 4 3 6% 7% 52%	2061
	21st to end	Night	16% 8% 3 6% 4 4 4 3 4 7% 40%	2104
October	1st to 10th	Night	18% 6% 2 6% 3 4 4 3 5% 6% 44%	2280
	11th to 20th	Night	19% 7% 2 6% 4 4 4 3 5% 7% 39%	2280
	21st to end	Night	25% 9% 2 5% 3 3 4 3 4 5% 37%	2508
November	1st to 10th	Night	14% 9% 3 6% 4 3 4 3 4 5% 46%	2373
	11th to 20th	Night	19% 15% 3 7% 4 3 4 3 5% 5% 31%	2596
	21st to end	Night	19% 16% 4 8% 4 4 4 3 4 5% 28%	2660
December	1st to 10th	Night	22% 20% 7% 10% 4 3 4 2 3 4 19%	2660
	11th to 20th	Night	20% 19% 7% 11% 5% 3 3 2 3 5% 22%	3285
	21st to end	Night	21% 22% 7% 10% 5% 4 3 3 4 5% 16%	4855

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	69% 6% 9% 11% 4 1	2837
	11th to 20th	Day	75% 5% 7% 9% 4	2840
	21st to end	Day	74% 5% 7% 10% 3	3124
February	1st to 10th	Day	65% 5% 10% 14% 6%	1710
	11th to 20th	Day	63% 7% 9% 13% 8%	1672
	21st to end	Day	63% 6% 9% 12% 9% 2	1588
March	1st to 10th	Day	55% 6% 10% 21% 6%	3435
	11th to 20th	Day	50% 8% 10% 23% 8% 1	3480
	21st to end	Day	53% 7% 9% 19% 11% 1	3815
April	1st to 10th	Day	54% 7% 10% 17% 11% 2	2199
	11th to 20th	Day	50% 7% 10% 14% 16% 2	2254
	21st to end	Day	51% 8% 10% 21% 9% 2	2460
May	1st to 10th	Day	56% 8% 8% 19% 7% 1	4120
	11th to 20th	Day	51% 9% 12% 20% 7% 1	4085
	21st to end	Day	40% 12% 16% 20% 11% 2	4729
June	1st to 10th	Day	45% 9% 13% 22% 11% 1	2660
	11th to 20th	Day	45% 10% 12% 22% 10% 1	2660
	21st to end	Day	44% 8% 14% 23% 10% 1	2660
July	1st to 10th	Day	40% 8% 13% 22% 14% 2	4199
	11th to 20th	Day	39% 8% 13% 27% 12% 1	4051
	21st to end	Day	47% 7% 10% 21% 13% 1	4324
August	1st to 10th	Day	47% 10% 13% 22% 8%	4091
	11th to 20th	Day	41% 7% 11% 30% 10%	4083
	21st to end	Day	34% 9% 15% 27% 14% 1	4262
September	1st to 10th	Day	39% 7% 11% 21% 19% 3	2280
	11th to 20th	Day	37% 6% 14% 27% 14% 3	2116
	21st to end	Day	49% 7% 12% 20% 13% 1	2076
October	1st to 10th	Day	35% 5% 9% 29% 19% 3	3160
	11th to 20th	Day	44% 5% 11% 21% 12% 7%	3140
	21st to end	Day	37% 5% 9% 28% 21% 1	3428
November	1st to 10th	Day	44% 5% 10% 21% 17% 4	1922
	11th to 20th	Day	53% 6% 10% 16% 12% 3	1587
	21st to end	Day	59% 5% 10% 15% 10%	1520
December	1st to 10th	Day	70% 6% 8% 11% 4 1	1520
	11th to 20th	Day	65% 4 8% 17% 5% 1	1906
	21st to end	Day	70% 5% 10% 11% 3	2783
January	1st to 10th	Night	70% 6% 8% 11% 4 1	4109
	11th to 20th	Night	72% 7% 10% 10% 2	4120
	21st to end	Night	74% 4 5% 13% 3 1	4532
February	1st to 10th	Night	62% 5% 9% 16% 7%	2470
	11th to 20th	Night	65% 5% 8% 15% 8%	2405
	21st to end	Night	62% 5% 9% 14% 8% 2	1861
March	1st to 10th	Night	55% 6% 8% 22% 7% 1	3418
	11th to 20th	Night	52% 9% 8% 24% 6% 1	3480
	21st to end	Night	47% 7% 8% 24% 12% 2	3817
April	1st to 10th	Night	54% 6% 9% 16% 12% 2	1979
	11th to 20th	Night	45% 7% 12% 17% 15% 3	1875
	21st to end	Night	46% 6% 13% 23% 9% 3	1734
May	1st to 10th	Night	59% 7% 9% 16% 8% 2	2840
	11th to 20th	Night	49% 9% 11% 21% 8% 1	2813
	21st to end	Night	41% 11% 15% 21% 9% 4	2843
June	1st to 10th	Night	39% 8% 13% 25% 13% 1	1520
	11th to 20th	Night	38% 9% 16% 23% 12% 1	1520
	21st to end	Night	38% 10% 14% 22% 15% 1	1520
July	1st to 10th	Night	43% 7% 11% 22% 14% 3	2633
	11th to 20th	Night	39% 9% 13% 24% 14% 1	2786
	21st to end	Night	44% 8% 11% 19% 16% 2	2988
August	1st to 10th	Night	46% 9% 17% 20% 8%	2814
	11th to 20th	Night	44% 7% 10% 22% 17% 1	2812
	21st to end	Night	33% 8% 13% 31% 12% 2	3348
September	1st to 10th	Night	38% 7% 12% 22% 17% 4	1900
	11th to 20th	Night	30% 7% 15% 25% 22% 1	2061
	21st to end	Night	43% 7% 12% 20% 17% 1	2104
October	1st to 10th	Night	36% 5% 9% 28% 18% 4	3800
	11th to 20th	Night	38% 5% 10% 23% 15% 9%	3779
	21st to end	Night	38% 3 7% 26% 23% 2	4120
November	1st to 10th	Night	41% 6% 11% 21% 18% 5%	2373
	11th to 20th	Night	54% 6% 8% 17% 13% 2	2596
	21st to end	Night	58% 6% 9% 18% 8% 1	2660
December	1st to 10th	Night	69% 5% 9% 13% 4 1	2660
	11th to 20th	Night	66% 5% 9% 15% 4 1	3288
	21st to end	Night	69% 7% 10% 10% 4	4855

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	33% 33% 20% 10% 4	270
	11th to 20th	Day	42% 26% 27% 4 1	270
	21st to end	Day	35% 33% 25% 4 3	297
February	1st to 10th	Day	38% 27% 29% 6% 1	270
	11th to 20th	Day	40% 31% 24% 4 1	270
	21st to end	Day	42% 26% 26% 5% 1	280
March	1st to 10th	Day	31% 25% 26% 14% 3	460
	11th to 20th	Day	35% 21% 28% 11% 4 1	460
	21st to end	Day	34% 20% 28% 14% 4	506
April	1st to 10th	Day	29% 24% 26% 15% 6%	460
	11th to 20th	Day	26% 20% 29% 15% 6% 4	452
	21st to end	Day	31% 19% 28% 15% 5% 1	460
May	1st to 10th	Day	29% 21% 26% 15% 7% 3	463
	11th to 20th	Day	23% 17% 30% 16% 10% 3	487
	21st to end	Day	16% 12% 26% 26% 14% 6%	529
June	1st to 10th	Day	19% 9% 29% 25% 14% 4	490
	11th to 20th	Day	17% 14% 25% 23% 17% 4	490
	21st to end	Day	16% 13% 29% 26% 14% 3	490
July	1st to 10th	Day	17% 7% 22% 26% 18% 11%	485
	11th to 20th	Day	12% 7% 26% 31% 16% 7%	484
	21st to end	Day	18% 6% 27% 24% 19% 6%	532
August	1st to 10th	Day	15% 7% 24% 28% 19% 8%	486
	11th to 20th	Day	16% 8% 21% 27% 19% 9%	479
	21st to end	Day	14% 6% 22% 27% 21% 10%	539
September	1st to 10th	Day	17% 9% 20% 28% 18% 9%	490
	11th to 20th	Day	13% 4 21% 28% 25% 8%	490
	21st to end	Day	26% 12% 23% 22% 12% 4	490
October	1st to 10th	Day	19% 11% 23% 27% 17% 2	490
	11th to 20th	Day	26% 13% 28% 22% 9% 2	490
	21st to end	Day	32% 17% 25% 19% 8%	539
November	1st to 10th	Day	20% 15% 29% 23% 10% 2	460
	11th to 20th	Day	34% 21% 23% 15% 5% 1	212
	21st to end	Day	31% 24% 32% 10% 2 1	180
December	1st to 10th	Day	32% 28% 27% 9% 2 2	180
	11th to 20th	Day	37% 26% 26% 11% 1	180
	21st to end	Day	36% 32% 16% 12% 3	204
January	1st to 10th	Night	31% 26% 27% 13% 3	760
	11th to 20th	Night	36% 21% 28% 14% 1	760
	21st to end	Night	31% 26% 27% 16% 1	836
February	1st to 10th	Night	30% 20% 28% 20% 2	760
	11th to 20th	Night	33% 27% 27% 12% 1	743
	21st to end	Night	32% 23% 29% 15% 1	628
March	1st to 10th	Night	27% 20% 29% 20% 4	760
	11th to 20th	Night	31% 20% 23% 20% 6% 1	760
	21st to end	Night	27% 19% 29% 20% 4 1	836
April	1st to 10th	Night	27% 19% 29% 20% 5%	760
	11th to 20th	Night	23% 14% 30% 23% 9% 1	751
	21st to end	Night	23% 11% 31% 26% 8%	594
May	1st to 10th	Night	23% 11% 25% 30% 9% 1	570
	11th to 20th	Night	24% 9% 24% 32% 11% 1	561
	21st to end	Night	11% 5% 25% 33% 24% 2	477
June	1st to 10th	Night	12% 7% 22% 40% 19% 1	380
	11th to 20th	Night	13% 7% 21% 39% 18% 2	380
	21st to end	Night	13% 4 23% 38% 21%	380
July	1st to 10th	Night	12% 5% 16% 38% 24% 4	458
	11th to 20th	Night	11% 5% 15% 37% 28% 4	552
	21st to end	Night	14% 4 15% 39% 27% 1	624
August	1st to 10th	Night	11% 3 14% 42% 28% 2	567
	11th to 20th	Night	14% 4 14% 35% 29% 3	564
	21st to end	Night	13% 4 16% 36% 28% 3	760
September	1st to 10th	Night	15% 5% 18% 34% 24% 4	760
	11th to 20th	Night	14% 3 18% 35% 26% 3	760
	21st to end	Night	19% 11% 20% 29% 19% 2	760
October	1st to 10th	Night	20% 8% 19% 31% 20% 3	760
	11th to 20th	Night	22% 11% 25% 29% 11% 1	760
	21st to end	Night	29% 14% 25% 25% 7%	836
November	1st to 10th	Night	19% 12% 26% 32% 11% 1	780
	11th to 20th	Night	29% 17% 24% 22% 7% 1	763
	21st to end	Night	29% 17% 26% 23% 5% 1	760
December	1st to 10th	Night	33% 20% 26% 16% 4	760
	11th to 20th	Night	31% 23% 25% 19% 3	760
	21st to end	Night	32% 19% 28% 20% 1	836

Page generated at 2024-11-08 06:44:46. Version ac07

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