Conneaut
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Conneaut clear sky chart from 2005-11-06 to 2024-09-14.

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	17% 12% 4 8% 5% 4 4 3 5% 7% 32%	100682
	Night	18% 14% 5% 9% 5% 4 4 3 5% 6% 28%	97162
Transparency	Day	52% 6% 11% 19% 10% 1	100489
	Night	57% 6% 10% 17% 9% 1	97025
Seeing	Day	22% 16% 29% 21% 10% 3	14353
	Night	24% 15% 26% 23% 11% 1	23957

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	20% 27% 9% 13% 5% 3 3 3 3 3 11%	2741
	11th to 20th	Day	13% 25% 10% 17% 6% 4 3 2 3 4 13%	2840
	21st to end	Day	24% 21% 9% 19% 6% 3 3 2 3 3 7%	3124
February	1st to 10th	Day	17% 20% 6% 15% 9% 4 4 2 4 4 15%	1710
	11th to 20th	Day	16% 17% 9% 14% 8% 4 4 2 4 4 17%	1663
	21st to end	Day	20% 16% 4 11% 5% 4 4 4 5% 5% 22%	1546
March	1st to 10th	Day	19% 15% 5% 8% 4 4 3 3 5% 6% 27%	3423
	11th to 20th	Day	12% 19% 6% 8% 4 4 3 3 5% 5% 31%	3480
	21st to end	Day	20% 13% 5% 11% 4 4 3 3 4 5% 29%	3815
April	1st to 10th	Day	17% 14% 3 7% 4 4 4 3 5% 6% 33%	2180
	11th to 20th	Day	19% 12% 3 6% 4 3 4 4 5% 5% 35%	2356
	21st to end	Day	21% 9% 2 7% 4 4 4 3 4 7% 35%	2470
May	1st to 10th	Day	19% 9% 3 7% 5% 5% 4 4 5% 7% 33%	4082
	11th to 20th	Day	18% 10% 3 6% 4 5% 4 3 5% 6% 35%	4081
	21st to end	Day	11% 6% 2 6% 4 4 4 4 6% 8% 44%	4814
June	1st to 10th	Day	15% 6% 2 5% 4 4 5% 4 7% 9% 39%	2660
	11th to 20th	Day	12% 6% 3 7% 5% 5% 4 3 6% 9% 41%	2660
	21st to end	Day	13% 5% 2 5% 3 4 4 4 7% 9% 43%	2660
July	1st to 10th	Day	9% 4 2 5% 4 4 5% 5% 6% 10% 45%	4419
	11th to 20th	Day	12% 4 2 5% 3 4 3 3 6% 10% 46%	4120
	21st to end	Day	10% 4 2 5% 5% 4 5% 4 7% 8% 45%	4466
August	1st to 10th	Day	16% 5% 2 6% 4 4 4 4 7% 9% 39%	4104
	11th to 20th	Day	15% 5% 2 7% 5% 5% 5% 4 7% 9% 35%	4044
	21st to end	Day	12% 5% 2 6% 4 4 5% 4 6% 8% 44%	4387
September	1st to 10th	Day	17% 6% 2 5% 3 4 5% 3 6% 7% 41%	2264
	11th to 20th	Day	12% 5% 2 5% 5% 4 4 4 5% 9% 45%	2014
	21st to end	Day	19% 7% 3 6% 5% 5% 4 3 5% 6% 37%	1980
October	1st to 10th	Day	19% 6% 2 7% 4 5% 4 4 6% 7% 36%	1814
	11th to 20th	Day	25% 9% 3 7% 5% 5% 4 3 6% 6% 28%	1800
	21st to end	Day	31% 13% 3 7% 5% 4 4 3 4 6% 21%	1980
November	1st to 10th	Day	17% 15% 4 7% 5% 3 4 4 6% 6% 31%	1708
	11th to 20th	Day	17% 23% 4 9% 4 3 4 2 5% 6% 23%	1555
	21st to end	Day	22% 25% 5% 9% 4 4 4 3 4 7% 14%	1520
December	1st to 10th	Day	19% 32% 7% 10% 4 3 2 2 4 4 12%	1520
	11th to 20th	Day	19% 25% 11% 10% 4 4 4 2 4 4 13%	1910
	21st to end	Day	25% 26% 6% 12% 5% 4 3 2 3 3 10%	2772
January	1st to 10th	Night	17% 28% 12% 15% 5% 3 3 2 2 3 9%	4201
	11th to 20th	Night	14% 24% 9% 15% 6% 6% 5% 3 3 4 10%	4120
	21st to end	Night	27% 22% 8% 15% 5% 3 2 2 3 3 10%	4532
February	1st to 10th	Night	19% 20% 5% 13% 8% 3 4 3 4 4 17%	2470
	11th to 20th	Night	18% 17% 7% 14% 6% 5% 5% 3 4 5% 18%	2403
	21st to end	Night	20% 16% 5% 14% 5% 4 4 3 3 5% 22%	1903
March	1st to 10th	Night	22% 16% 4 7% 5% 3 3 3 4 5% 30%	3428
	11th to 20th	Night	17% 19% 5% 7% 3 3 3 3 4 5% 31%	3480
	21st to end	Night	18% 13% 4 10% 4 3 3 3 4 4 34%	3817
April	1st to 10th	Night	19% 15% 4 6% 5% 4 4 3 5% 5% 30%	2000
	11th to 20th	Night	20% 9% 2 7% 5% 3 5% 4 6% 6% 32%	1789
	21st to end	Night	16% 11% 3 6% 5% 4 5% 5% 5% 6% 33%	1710
May	1st to 10th	Night	24% 9% 3 6% 5% 4 4 3 5% 7% 32%	2813
	11th to 20th	Night	16% 9% 3 8% 5% 4 5% 3 5% 7% 36%	2812
	21st to end	Night	12% 4 2 4 3 3 4 3 7% 10% 45%	2736
June	1st to 10th	Night	11% 6% 2 8% 6% 5% 5% 4 6% 9% 40%	1520
	11th to 20th	Night	10% 6% 3 8% 5% 5% 4 4 6% 7% 43%	1520
	21st to end	Night	13% 5% 3 6% 5% 5% 4 4 6% 10% 40%	1520
July	1st to 10th	Night	12% 6% 2 6% 4 4 4 3 5% 9% 44%	2537
	11th to 20th	Night	12% 5% 2 6% 4 4 4 4 6% 9% 46%	2840
	21st to end	Night	9% 4 2 6% 5% 5% 5% 5% 7% 8% 45%	3087
August	1st to 10th	Night	12% 6% 3 8% 5% 5% 5% 4 7% 7% 39%	2825
	11th to 20th	Night	18% 6% 3 7% 5% 5% 4 3 5% 6% 38%	2785
	21st to end	Night	11% 5% 3 6% 4 4 5% 4 7% 8% 42%	3236
September	1st to 10th	Night	14% 8% 2 5% 3 3 4 4 6% 8% 44%	1913
	11th to 20th	Night	14% 5% 2 5% 4 4 3 3 6% 7% 48%	2024
	21st to end	Night	16% 6% 2 7% 5% 5% 5% 4 5% 7% 37%	1980
October	1st to 10th	Night	19% 7% 3 7% 4 3 3 3 5% 7% 38%	2146
	11th to 20th	Night	24% 9% 2 8% 5% 4 4 4 5% 7% 27%	2160
	21st to end	Night	30% 12% 4 6% 5% 4 4 3 4 5% 24%	2376
November	1st to 10th	Night	19% 14% 3 8% 5% 4 4 3 4 5% 31%	2368
	11th to 20th	Night	20% 20% 4 9% 4 5% 4 4 4 5% 22%	2622
	21st to end	Night	22% 24% 6% 7% 5% 3 3 3 4 4 18%	2660
December	1st to 10th	Night	23% 29% 8% 9% 4 3 3 3 3 3 12%	2660
	11th to 20th	Night	19% 27% 8% 11% 4 3 3 3 3 4 14%	3285
	21st to end	Night	24% 26% 6% 11% 5% 4 4 3 4 4 9%	4884

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	79% 7% 7% 6% 1	2742
	11th to 20th	Day	78% 2 9% 8% 3	2840
	21st to end	Day	86% 3 6% 4 2	3124
February	1st to 10th	Day	74% 4 7% 9% 4	1710
	11th to 20th	Day	73% 3 7% 11% 6%	1672
	21st to end	Day	63% 6% 10% 14% 5% 2	1546
March	1st to 10th	Day	57% 7% 9% 23% 4	3423
	11th to 20th	Day	54% 7% 16% 16% 5% 1	3480
	21st to end	Day	57% 6% 8% 17% 10% 1	3815
April	1st to 10th	Day	52% 6% 12% 17% 13% 1	2180
	11th to 20th	Day	51% 5% 10% 20% 12% 2	2356
	21st to end	Day	52% 5% 10% 19% 11% 3	2470
May	1st to 10th	Day	51% 7% 8% 23% 10% 1	4120
	11th to 20th	Day	49% 7% 11% 22% 9% 2	4085
	21st to end	Day	38% 9% 12% 22% 15% 4	4828
June	1st to 10th	Day	41% 8% 12% 24% 13% 1	2660
	11th to 20th	Day	41% 7% 14% 23% 14% 1	2660
	21st to end	Day	38% 7% 13% 25% 15% 2	2660
July	1st to 10th	Day	35% 6% 15% 25% 17% 3	4349
	11th to 20th	Day	34% 6% 13% 28% 18% 1	4051
	21st to end	Day	37% 7% 15% 23% 17% 1	4324
August	1st to 10th	Day	41% 7% 15% 24% 12%	4091
	11th to 20th	Day	42% 9% 14% 28% 6% 1	4083
	21st to end	Day	37% 6% 14% 28% 14% 1	4387
September	1st to 10th	Day	42% 6% 14% 22% 13% 2	2264
	11th to 20th	Day	37% 7% 14% 26% 15% 1	2014
	21st to end	Day	48% 6% 12% 22% 12% 1	1980
October	1st to 10th	Day	46% 8% 13% 19% 12% 1	1814
	11th to 20th	Day	56% 6% 14% 17% 7% 1	1800
	21st to end	Day	64% 5% 11% 13% 6% 1	1980
November	1st to 10th	Day	54% 6% 10% 18% 11% 1	1708
	11th to 20th	Day	63% 6% 10% 13% 7% 2	1555
	21st to end	Day	71% 5% 9% 10% 4	1520
December	1st to 10th	Day	77% 5% 8% 9% 1	1520
	11th to 20th	Day	76% 5% 8% 9% 2	1906
	21st to end	Day	82% 5% 6% 6% 1	2772
January	1st to 10th	Night	82% 4 6% 6% 2	4201
	11th to 20th	Night	76% 5% 10% 7% 2	4120
	21st to end	Night	81% 4 6% 6% 2	4532
February	1st to 10th	Night	71% 5% 9% 12% 3	2470
	11th to 20th	Night	70% 4 8% 13% 5%	2405
	21st to end	Night	67% 5% 9% 12% 7% 1	1903
March	1st to 10th	Night	58% 5% 11% 18% 8%	3428
	11th to 20th	Night	55% 5% 15% 17% 8% 1	3480
	21st to end	Night	53% 5% 10% 18% 13% 1	3817
April	1st to 10th	Night	56% 5% 9% 17% 11% 2	2000
	11th to 20th	Night	50% 7% 10% 18% 12% 3	1789
	21st to end	Night	49% 6% 10% 20% 11% 3	1710
May	1st to 10th	Night	53% 5% 9% 18% 11% 4	2840
	11th to 20th	Night	46% 7% 12% 23% 11% 2	2813
	21st to end	Night	32% 7% 14% 27% 17% 3	2743
June	1st to 10th	Night	40% 7% 11% 24% 15% 2	1520
	11th to 20th	Night	38% 6% 13% 21% 19% 3	1520
	21st to end	Night	39% 8% 12% 23% 16% 1	1520
July	1st to 10th	Night	38% 6% 11% 22% 19% 4	2497
	11th to 20th	Night	34% 6% 12% 28% 16% 4	2786
	21st to end	Night	35% 7% 14% 22% 21% 1	2988
August	1st to 10th	Night	41% 8% 11% 27% 12% 1	2814
	11th to 20th	Night	46% 6% 12% 26% 10% 1	2812
	21st to end	Night	36% 7% 14% 28% 14% 2	3236
September	1st to 10th	Night	37% 7% 12% 27% 14% 3	1913
	11th to 20th	Night	35% 6% 13% 26% 20% 1	2024
	21st to end	Night	46% 6% 11% 21% 15% 1	1980
October	1st to 10th	Night	44% 5% 12% 21% 16% 1	2146
	11th to 20th	Night	55% 7% 11% 17% 10% 1	2160
	21st to end	Night	62% 5% 10% 14% 8% 1	2376
November	1st to 10th	Night	54% 5% 12% 18% 9% 2	2368
	11th to 20th	Night	64% 6% 8% 14% 6% 2	2622
	21st to end	Night	70% 5% 9% 13% 4	2660
December	1st to 10th	Night	77% 5% 9% 6% 2	2660
	11th to 20th	Night	75% 5% 11% 8% 2	3288
	21st to end	Night	79% 7% 7% 5% 1	4884

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% 32% 25% 11% 5%	243
	11th to 20th	Day	31% 33% 24% 8% 3	270
	21st to end	Day	27% 31% 31% 8% 2	297
February	1st to 10th	Day	30% 26% 34% 9%	270
	11th to 20th	Day	30% 29% 32% 8% 1	270
	21st to end	Day	34% 30% 28% 8%	225
March	1st to 10th	Day	28% 23% 34% 11% 4	448
	11th to 20th	Day	28% 20% 35% 12% 4 1	460
	21st to end	Day	33% 21% 27% 16% 3	506
April	1st to 10th	Day	23% 28% 29% 15% 5%	460
	11th to 20th	Day	29% 19% 27% 17% 6% 2	452
	21st to end	Day	26% 18% 33% 17% 5% 1	460
May	1st to 10th	Day	28% 16% 31% 18% 5% 2	463
	11th to 20th	Day	20% 14% 30% 23% 11% 2	487
	21st to end	Day	15% 8% 29% 29% 15% 5%	529
June	1st to 10th	Day	17% 10% 36% 25% 10% 2	490
	11th to 20th	Day	15% 11% 30% 29% 13% 2	490
	21st to end	Day	15% 10% 32% 30% 11% 2	490
July	1st to 10th	Day	13% 5% 27% 30% 18% 7%	485
	11th to 20th	Day	14% 6% 26% 32% 16% 6%	484
	21st to end	Day	10% 4 33% 32% 15% 5%	532
August	1st to 10th	Day	12% 7% 26% 30% 18% 7%	486
	11th to 20th	Day	16% 6% 24% 30% 17% 7%	479
	21st to end	Day	13% 8% 24% 31% 18% 6%	539
September	1st to 10th	Day	16% 9% 23% 28% 17% 7%	490
	11th to 20th	Day	11% 6% 25% 30% 21% 8%	463
	21st to end	Day	18% 13% 28% 23% 12% 6%	450
October	1st to 10th	Day	18% 10% 29% 22% 17% 4	450
	11th to 20th	Day	29% 18% 30% 17% 5% 1	450
	21st to end	Day	38% 17% 28% 16% 2	495
November	1st to 10th	Day	28% 21% 26% 16% 8% 1	306
	11th to 20th	Day	39% 22% 24% 11% 4	196
	21st to end	Day	34% 24% 33% 9%	180
December	1st to 10th	Day	32% 30% 27% 8% 2 1	180
	11th to 20th	Day	26% 36% 27% 11% 1	180
	21st to end	Day	35% 25% 29% 9% 2	198
January	1st to 10th	Night	30% 26% 29% 10% 4	760
	11th to 20th	Night	34% 22% 27% 14% 2	760
	21st to end	Night	27% 23% 31% 16% 2	836
February	1st to 10th	Night	30% 22% 29% 16% 3	760
	11th to 20th	Night	27% 23% 30% 17% 3	743
	21st to end	Night	29% 22% 31% 17% 1	628
March	1st to 10th	Night	26% 19% 29% 22% 4	760
	11th to 20th	Night	24% 20% 31% 19% 5% 1	760
	21st to end	Night	26% 15% 28% 24% 6% 1	836
April	1st to 10th	Night	25% 16% 29% 24% 5%	760
	11th to 20th	Night	25% 12% 31% 23% 8% 1	665
	21st to end	Night	20% 12% 30% 30% 7% 1	570
May	1st to 10th	Night	24% 8% 24% 31% 12% 1	570
	11th to 20th	Night	20% 6% 26% 36% 11% 1	561
	21st to end	Night	13% 6% 24% 32% 23% 3	416
June	1st to 10th	Night	13% 4 30% 35% 16% 2	380
	11th to 20th	Night	13% 6% 24% 39% 18% 1	380
	21st to end	Night	13% 6% 27% 34% 20%	380
July	1st to 10th	Night	10% 5% 19% 40% 22% 5%	374
	11th to 20th	Night	11% 4 23% 33% 26% 3	552
	21st to end	Night	11% 3 21% 37% 26% 3	624
August	1st to 10th	Night	11% 3 17% 40% 24% 5%	567
	11th to 20th	Night	14% 2 17% 32% 29% 5%	564
	21st to end	Night	15% 5% 22% 29% 26% 3	687
September	1st to 10th	Night	16% 7% 18% 29% 24% 5%	760
	11th to 20th	Night	14% 5% 17% 33% 26% 5%	736
	21st to end	Night	19% 11% 22% 26% 18% 5%	720
October	1st to 10th	Night	23% 11% 22% 24% 17% 3	720
	11th to 20th	Night	30% 15% 27% 20% 7% 1	720
	21st to end	Night	37% 15% 27% 18% 3	792
November	1st to 10th	Night	27% 16% 27% 22% 8% 1	740
	11th to 20th	Night	33% 20% 27% 14% 5% 1	760
	21st to end	Night	35% 22% 27% 12% 4	760
December	1st to 10th	Night	37% 24% 24% 10% 4	760
	11th to 20th	Night	32% 28% 26% 12% 2	760
	21st to end	Night	32% 23% 30% 13% 1	836

Page generated at 2024-09-11 10:00:07. Version ac07

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