St Clairsville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the St Clairsville clear sky chart from 2005-11-06 to 2024-11-02.

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	15% 10% 4 8% 5% 5% 5% 4 6% 7% 32%	100913
	Night	15% 11% 4 8% 5% 4 4 3 5% 6% 34%	97989
Transparency	Day	49% 7% 11% 20% 11% 1	100724
	Night	50% 7% 11% 20% 11% 2	97848
Seeing	Day	22% 16% 27% 20% 11% 4	14736
	Night	21% 12% 27% 26% 12% 2	24635

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% 19% 6% 11% 5% 4 3 2 4 6% 20%	2836
	11th to 20th	Day	13% 23% 9% 13% 7% 4 3 2 4 4 19%	2840
	21st to end	Day	24% 22% 7% 12% 6% 4 3 2 3 4 13%	3124
February	1st to 10th	Day	20% 17% 5% 9% 6% 4 4 3 4 4 24%	1710
	11th to 20th	Day	15% 14% 6% 13% 5% 4 3 3 6% 7% 24%	1701
	21st to end	Day	19% 15% 6% 9% 4 3 3 4 4 5% 29%	1570
March	1st to 10th	Day	20% 15% 4 9% 5% 4 3 3 4 5% 27%	3426
	11th to 20th	Day	13% 9% 4 9% 6% 5% 5% 4 5% 6% 35%	3480
	21st to end	Day	20% 9% 3 8% 5% 4 4 4 5% 7% 32%	3815
April	1st to 10th	Day	13% 13% 4 8% 6% 4 5% 4 5% 7% 31%	2145
	11th to 20th	Day	15% 10% 3 8% 5% 5% 4 4 5% 6% 35%	2337
	21st to end	Day	19% 9% 2 7% 5% 5% 4 4 6% 6% 32%	2470
May	1st to 10th	Day	21% 9% 3 8% 5% 5% 5% 4 5% 7% 27%	4082
	11th to 20th	Day	19% 9% 3 8% 4 5% 4 3 5% 7% 31%	4081
	21st to end	Day	11% 6% 2 7% 5% 5% 6% 5% 8% 10% 35%	4476
June	1st to 10th	Day	11% 8% 3 7% 5% 5% 5% 4 7% 9% 36%	2646
	11th to 20th	Day	11% 7% 3 7% 5% 5% 5% 5% 8% 9% 35%	2660
	21st to end	Day	12% 6% 2 7% 4 5% 6% 5% 7% 9% 36%	2589
July	1st to 10th	Day	9% 6% 3 7% 5% 5% 6% 4 6% 9% 39%	4120
	11th to 20th	Day	9% 5% 2 7% 5% 5% 5% 5% 7% 9% 41%	4120
	21st to end	Day	12% 8% 3 8% 6% 6% 5% 4 6% 9% 33%	4466
August	1st to 10th	Day	11% 7% 3 8% 5% 7% 6% 5% 7% 9% 32%	4104
	11th to 20th	Day	10% 6% 3 8% 5% 5% 7% 5% 8% 9% 35%	4044
	21st to end	Day	6% 4 2 6% 5% 6% 6% 6% 7% 9% 42%	4377
September	1st to 10th	Day	15% 5% 2 5% 4 4 4 3 5% 7% 47%	2212
	11th to 20th	Day	9% 6% 2 5% 4 4 4 4 6% 9% 45%	2090
	21st to end	Day	18% 9% 3 7% 4 4 5% 3 4 7% 35%	2090
October	1st to 10th	Day	13% 6% 3 7% 4 4 5% 3 6% 7% 41%	1940
	11th to 20th	Day	16% 8% 3 8% 5% 4 5% 3 5% 5% 39%	1900
	21st to end	Day	21% 9% 3 7% 4 3 4 3 4 6% 35%	2090
November	1st to 10th	Day	10% 10% 3 6% 5% 4 5% 3 5% 6% 45%	1750
	11th to 20th	Day	17% 15% 3 6% 5% 4 3 3 4 6% 33%	1699
	21st to end	Day	17% 13% 5% 8% 6% 4 4 4 5% 4 29%	1520
December	1st to 10th	Day	20% 16% 5% 12% 5% 5% 4 3 5% 5% 19%	1520
	11th to 20th	Day	18% 18% 5% 12% 5% 3 3 3 5% 5% 22%	1910
	21st to end	Day	23% 22% 5% 10% 5% 4 4 3 4 5% 14%	2973
January	1st to 10th	Night	16% 19% 7% 13% 5% 5% 4 3 4 5% 20%	4109
	11th to 20th	Night	16% 18% 7% 15% 6% 5% 5% 3 4 4 16%	4120
	21st to end	Night	27% 18% 6% 13% 5% 3 3 2 3 3 17%	4532
February	1st to 10th	Night	19% 14% 4 10% 6% 5% 4 3 4 5% 27%	2470
	11th to 20th	Night	19% 14% 4 10% 5% 6% 4 4 5% 5% 25%	2361
	21st to end	Night	18% 15% 5% 10% 5% 5% 4 3 4 5% 25%	1884
March	1st to 10th	Night	21% 11% 4 7% 5% 4 4 2 4 6% 33%	3426
	11th to 20th	Night	14% 9% 5% 8% 5% 5% 4 4 5% 6% 35%	3480
	21st to end	Night	17% 9% 3 7% 5% 4 4 3 5% 6% 38%	3817
April	1st to 10th	Night	17% 13% 3 7% 4 4 4 3 6% 5% 33%	2033
	11th to 20th	Night	16% 8% 2 7% 5% 4 5% 4 6% 8% 36%	1807
	21st to end	Night	15% 10% 3 7% 5% 4 4 4 5% 7% 39%	1710
May	1st to 10th	Night	26% 11% 4 7% 4 5% 3 3 5% 6% 26%	2813
	11th to 20th	Night	18% 9% 3 7% 5% 4 3 3 4 7% 38%	2812
	21st to end	Night	10% 6% 3 7% 4 4 5% 5% 7% 10% 40%	3079
June	1st to 10th	Night	8% 7% 3 6% 5% 5% 6% 4 6% 8% 44%	1530
	11th to 20th	Night	10% 5% 2 5% 4 5% 6% 5% 8% 11% 39%	1520
	21st to end	Night	11% 5% 2 5% 5% 5% 4 5% 6% 8% 44%	1584
July	1st to 10th	Night	9% 7% 3 8% 5% 4 4 3 6% 8% 43%	2840
	11th to 20th	Night	9% 6% 2 7% 4 4 5% 3 6% 9% 45%	2840
	21st to end	Night	8% 8% 3 7% 5% 5% 5% 4 6% 8% 41%	3087
August	1st to 10th	Night	10% 8% 3 8% 5% 5% 6% 5% 6% 10% 35%	2825
	11th to 20th	Night	10% 8% 3 8% 4 5% 4 4 7% 7% 41%	2785
	21st to end	Night	6% 4 2 6% 5% 5% 5% 4 7% 9% 46%	3247
September	1st to 10th	Night	12% 5% 2 5% 4 4 4 3 5% 6% 50%	1965
	11th to 20th	Night	9% 5% 2 5% 4 3 3 3 5% 8% 54%	2090
	21st to end	Night	15% 8% 2 7% 4 4 5% 4 4 6% 42%	2090
October	1st to 10th	Night	13% 6% 2 6% 4 4 4 3 5% 7% 45%	2238
	11th to 20th	Night	14% 8% 3 7% 4 5% 4 4 5% 7% 40%	2280
	21st to end	Night	21% 8% 3 6% 4 4 3 3 5% 7% 37%	2508
November	1st to 10th	Night	12% 9% 3 5% 4 3 3 3 5% 7% 47%	2347
	11th to 20th	Night	16% 12% 3 7% 5% 5% 4 3 5% 5% 34%	2477
	21st to end	Night	18% 12% 4 8% 5% 5% 4 3 5% 5% 30%	2660
December	1st to 10th	Night	22% 14% 5% 10% 5% 5% 4 4 5% 5% 22%	2660
	11th to 20th	Night	17% 16% 6% 11% 5% 4 3 3 5% 5% 24%	3285
	21st to end	Night	21% 19% 6% 10% 6% 5% 4 3 4 5% 17%	4678

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	66% 5% 10% 13% 5%	2837
	11th to 20th	Day	71% 4 9% 11% 5% 1	2840
	21st to end	Day	76% 4 6% 10% 3 1	3124
February	1st to 10th	Day	64% 4 9% 14% 8% 1	1710
	11th to 20th	Day	60% 6% 10% 16% 8% 1	1710
	21st to end	Day	58% 4 10% 17% 8% 2	1570
March	1st to 10th	Day	58% 7% 9% 20% 6%	3426
	11th to 20th	Day	47% 8% 11% 25% 9% 1	3480
	21st to end	Day	51% 5% 10% 20% 13% 1	3815
April	1st to 10th	Day	51% 7% 11% 18% 10% 3	2145
	11th to 20th	Day	48% 7% 11% 16% 16% 3	2337
	21st to end	Day	50% 7% 10% 19% 11% 2	2470
May	1st to 10th	Day	54% 8% 9% 20% 7% 1	4120
	11th to 20th	Day	49% 8% 11% 21% 11% 1	4085
	21st to end	Day	39% 11% 15% 21% 11% 3	4489
June	1st to 10th	Day	42% 8% 14% 23% 12% 1	2646
	11th to 20th	Day	41% 10% 14% 22% 12% 1	2660
	21st to end	Day	41% 9% 13% 21% 13% 1	2589
July	1st to 10th	Day	40% 7% 13% 23% 16% 2	4055
	11th to 20th	Day	37% 7% 11% 28% 16% 1	4051
	21st to end	Day	45% 7% 12% 17% 16% 2	4324
August	1st to 10th	Day	44% 9% 14% 22% 10%	4091
	11th to 20th	Day	41% 8% 11% 27% 12%	4083
	21st to end	Day	34% 9% 13% 28% 14% 2	4377
September	1st to 10th	Day	37% 6% 12% 21% 20% 4	2212
	11th to 20th	Day	34% 6% 14% 28% 15% 3	2090
	21st to end	Day	49% 5% 10% 21% 15% 1	2090
October	1st to 10th	Day	40% 7% 12% 22% 17% 1	1940
	11th to 20th	Day	46% 6% 11% 23% 12% 1	1900
	21st to end	Day	50% 5% 11% 20% 13% 1	2090
November	1st to 10th	Day	40% 5% 10% 26% 16% 3	1750
	11th to 20th	Day	52% 5% 11% 19% 11% 2	1699
	21st to end	Day	56% 6% 11% 17% 9% 1	1520
December	1st to 10th	Day	68% 5% 10% 13% 3	1520
	11th to 20th	Day	64% 5% 9% 17% 5%	1906
	21st to end	Day	71% 7% 10% 9% 3	2973
January	1st to 10th	Night	67% 6% 8% 14% 4	4109
	11th to 20th	Night	70% 6% 10% 10% 3	4120
	21st to end	Night	73% 3 6% 13% 3 1	4532
February	1st to 10th	Night	60% 5% 10% 17% 7% 1	2470
	11th to 20th	Night	61% 4 9% 17% 7% 1	2363
	21st to end	Night	62% 5% 9% 14% 8% 2	1884
March	1st to 10th	Night	53% 5% 8% 23% 10% 1	3426
	11th to 20th	Night	47% 8% 10% 27% 7% 1	3480
	21st to end	Night	45% 6% 9% 27% 11% 2	3817
April	1st to 10th	Night	50% 6% 10% 18% 13% 2	2033
	11th to 20th	Night	44% 8% 13% 16% 15% 4	1807
	21st to end	Night	44% 7% 12% 21% 15% 2	1710
May	1st to 10th	Night	58% 7% 9% 17% 8% 2	2840
	11th to 20th	Night	45% 8% 9% 24% 11% 1	2813
	21st to end	Night	34% 11% 16% 23% 12% 4	3087
June	1st to 10th	Night	36% 9% 12% 23% 17% 3	1530
	11th to 20th	Night	35% 9% 16% 22% 16% 2	1520
	21st to end	Night	35% 10% 13% 24% 16% 2	1584
July	1st to 10th	Night	39% 6% 10% 24% 17% 4	2795
	11th to 20th	Night	34% 7% 13% 29% 16% 1	2786
	21st to end	Night	38% 9% 11% 19% 19% 4	2988
August	1st to 10th	Night	43% 10% 15% 23% 10% 1	2814
	11th to 20th	Night	39% 8% 9% 23% 19% 1	2812
	21st to end	Night	31% 8% 14% 30% 14% 3	3247
September	1st to 10th	Night	34% 7% 10% 21% 21% 6%	1965
	11th to 20th	Night	29% 6% 14% 26% 24% 2	2090
	21st to end	Night	42% 7% 10% 21% 18% 1	2090
October	1st to 10th	Night	38% 6% 12% 23% 17% 3	2238
	11th to 20th	Night	43% 7% 10% 24% 15% 2	2280
	21st to end	Night	47% 4 9% 23% 14% 2	2508
November	1st to 10th	Night	38% 5% 12% 23% 18% 4	2347
	11th to 20th	Night	51% 5% 10% 18% 13% 2	2477
	21st to end	Night	55% 6% 11% 19% 8% 1	2660
December	1st to 10th	Night	64% 6% 10% 15% 5% 1	2660
	11th to 20th	Night	61% 5% 12% 17% 4	3288
	21st to end	Night	69% 7% 9% 12% 3	4678

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% 25% 28% 10% 5%	270
	11th to 20th	Day	36% 27% 28% 8% 1	270
	21st to end	Day	34% 31% 28% 5% 2	297
February	1st to 10th	Day	37% 23% 31% 9% 1	270
	11th to 20th	Day	38% 29% 27% 5% 1	270
	21st to end	Day	35% 31% 29% 5%	225
March	1st to 10th	Day	31% 23% 29% 14% 4	451
	11th to 20th	Day	30% 20% 32% 13% 4 1	460
	21st to end	Day	30% 21% 31% 15% 3 1	506
April	1st to 10th	Day	27% 21% 30% 16% 6% 1	460
	11th to 20th	Day	24% 23% 26% 16% 8% 3	452
	21st to end	Day	26% 21% 32% 14% 6% 2	460
May	1st to 10th	Day	25% 25% 25% 16% 8% 2	463
	11th to 20th	Day	21% 15% 31% 18% 10% 4	487
	21st to end	Day	14% 10% 28% 25% 18% 5%	529
June	1st to 10th	Day	13% 12% 28% 31% 13% 4	490
	11th to 20th	Day	14% 14% 24% 31% 12% 6%	490
	21st to end	Day	13% 12% 33% 25% 13% 4	490
July	1st to 10th	Day	14% 7% 23% 27% 18% 11%	485
	11th to 20th	Day	11% 7% 26% 30% 17% 9%	484
	21st to end	Day	15% 7% 24% 28% 18% 8%	532
August	1st to 10th	Day	13% 6% 22% 31% 20% 8%	486
	11th to 20th	Day	14% 7% 24% 29% 16% 11%	479
	21st to end	Day	9% 5% 25% 26% 23% 11%	539
September	1st to 10th	Day	16% 7% 23% 27% 20% 8%	490
	11th to 20th	Day	10% 4 19% 30% 28% 9%	490
	21st to end	Day	24% 12% 25% 20% 14% 4	490
October	1st to 10th	Day	15% 9% 30% 26% 16% 4	490
	11th to 20th	Day	22% 15% 28% 23% 10% 2	490
	21st to end	Day	26% 18% 29% 19% 7% 1	539
November	1st to 10th	Day	18% 18% 37% 15% 10% 2	342
	11th to 20th	Day	30% 19% 30% 13% 8% 1	264
	21st to end	Day	25% 27% 33% 14% 1	180
December	1st to 10th	Day	32% 23% 33% 7% 5% 1	180
	11th to 20th	Day	28% 29% 28% 12% 2	180
	21st to end	Day	33% 27% 27% 11% 2	256
January	1st to 10th	Night	29% 20% 32% 16% 3	760
	11th to 20th	Night	30% 20% 32% 15% 3	760
	21st to end	Night	27% 22% 30% 18% 3	836
February	1st to 10th	Night	29% 18% 29% 23% 1	760
	11th to 20th	Night	30% 20% 33% 15% 1	743
	21st to end	Night	29% 19% 32% 18% 2	628
March	1st to 10th	Night	24% 19% 33% 21% 4	760
	11th to 20th	Night	25% 20% 28% 21% 6% 1	760
	21st to end	Night	26% 17% 31% 21% 5% 1	836
April	1st to 10th	Night	25% 16% 31% 22% 6%	760
	11th to 20th	Night	20% 15% 33% 20% 10% 1	683
	21st to end	Night	19% 9% 37% 27% 6% 1	570
May	1st to 10th	Night	21% 13% 23% 31% 11% 1	570
	11th to 20th	Night	20% 9% 27% 29% 14% 1	561
	21st to end	Night	10% 4 23% 39% 21% 3	617
June	1st to 10th	Night	8% 6% 28% 38% 19% 1	390
	11th to 20th	Night	10% 7% 21% 40% 22%	380
	21st to end	Night	9% 5% 25% 41% 19% 1	444
July	1st to 10th	Night	11% 4 18% 36% 25% 6%	555
	11th to 20th	Night	8% 4 20% 35% 29% 4	552
	21st to end	Night	11% 4 15% 36% 32% 2	624
August	1st to 10th	Night	8% 3 16% 42% 29% 3	567
	11th to 20th	Night	10% 3 16% 36% 29% 6%	564
	21st to end	Night	10% 3 19% 31% 31% 6%	698
September	1st to 10th	Night	13% 4 18% 32% 28% 5%	760
	11th to 20th	Night	10% 3 18% 36% 28% 5%	760
	21st to end	Night	19% 7% 23% 27% 20% 3	760
October	1st to 10th	Night	16% 8% 23% 30% 21% 3	760
	11th to 20th	Night	21% 10% 29% 28% 11% 1	760
	21st to end	Night	25% 12% 27% 28% 8% 1	836
November	1st to 10th	Night	18% 11% 28% 29% 14%	745
	11th to 20th	Night	24% 16% 28% 23% 7% 1	760
	21st to end	Night	27% 13% 31% 23% 5% 1	760
December	1st to 10th	Night	30% 17% 30% 18% 5%	760
	11th to 20th	Night	29% 18% 31% 20% 3	760
	21st to end	Night	30% 16% 32% 19% 2	836

Page generated at 2024-10-30 01:22:55. Version ac07

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