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 2024-01-31.

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% 5% 7% 5% 3 4 4 5% 7% 31%	74774
	Night	18% 14% 5% 8% 6% 3 4 4 5% 6% 28%	75357
Transparency	Day	35% 37% 8% 12% 7% 1	74490
	Night	39% 37% 7% 11% 6% 1	75160
Seeing	Day	22% 16% 29% 21% 10% 3	13474
	Night	24% 15% 26% 23% 11% 1	23232

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% 20% 9% 15% 8% 3 4 4 4 4 11%	1650
	11th to 20th	Day	18% 21% 10% 14% 8% 3 3 3 3 4 12%	1710
	21st to end	Day	17% 20% 9% 16% 10% 3 4 4 4 4 10%	1872
February	1st to 10th	Day	18% 18% 8% 14% 10% 4 4 3 3 3 14%	1620
	11th to 20th	Day	17% 16% 9% 13% 10% 4 4 3 4 4 16%	1573
	21st to end	Day	20% 15% 6% 11% 5% 3 5% 5% 5% 5% 22%	1458
March	1st to 10th	Day	18% 14% 7% 9% 6% 3 3 4 5% 7% 26%	1968
	11th to 20th	Day	16% 14% 6% 7% 5% 3 4 4 5% 6% 29%	1980
	21st to end	Day	21% 13% 5% 7% 5% 3 4 4 4 5% 29%	2178
April	1st to 10th	Day	17% 13% 4 5% 5% 3 4 4 5% 6% 33%	2065
	11th to 20th	Day	19% 12% 3 5% 4 2 4 5% 5% 5% 35%	2230
	21st to end	Day	21% 8% 3 6% 5% 3 4 4 4 6% 35%	2340
May	1st to 10th	Day	18% 9% 3 5% 6% 3 5% 5% 5% 7% 34%	2340
	11th to 20th	Day	18% 7% 3 5% 5% 4 5% 4 6% 7% 36%	2301
	21st to end	Day	11% 5% 2 5% 5% 3 5% 6% 6% 8% 42%	2716
June	1st to 10th	Day	15% 6% 2 4 5% 3 5% 4 7% 9% 40%	2520
	11th to 20th	Day	13% 6% 2 6% 5% 4 4 4 5% 9% 41%	2520
	21st to end	Day	13% 5% 2 5% 4 3 4 5% 6% 9% 44%	2520
July	1st to 10th	Day	10% 4 2 4 4 3 5% 5% 6% 9% 48%	2513
	11th to 20th	Day	12% 4 3 5% 4 3 4 4 6% 10% 43%	2340
	21st to end	Day	11% 4 3 3 5% 3 5% 6% 8% 9% 43%	2547
August	1st to 10th	Day	10% 5% 2 5% 4 3 4 6% 7% 9% 44%	2327
	11th to 20th	Day	11% 5% 2 6% 6% 3 5% 6% 7% 10% 39%	2303
	21st to end	Day	13% 5% 3 6% 5% 3 5% 5% 6% 8% 42%	2499
September	1st to 10th	Day	17% 6% 3 5% 4 3 5% 5% 6% 8% 39%	2145
	11th to 20th	Day	13% 5% 3 4 5% 4 4 5% 5% 9% 44%	1980
	21st to end	Day	19% 6% 3 5% 5% 4 4 4 5% 6% 37%	1980
October	1st to 10th	Day	19% 6% 2 6% 5% 4 4 5% 5% 7% 36%	1814
	11th to 20th	Day	25% 9% 3 6% 6% 4 4 4 6% 6% 28%	1800
	21st to end	Day	31% 12% 3 6% 5% 3 4 4 4 6% 21%	1980
November	1st to 10th	Day	18% 14% 4 6% 5% 2 4 4 5% 6% 31%	1708
	11th to 20th	Day	18% 21% 5% 8% 5% 3 4 3 5% 6% 23%	1555
	21st to end	Day	22% 24% 6% 8% 5% 3 4 4 3 7% 14%	1520
December	1st to 10th	Day	19% 29% 10% 9% 5% 3 2 3 4 4 12%	1520
	11th to 20th	Day	19% 24% 13% 9% 5% 3 4 4 4 4 13%	1910
	21st to end	Day	26% 25% 7% 11% 6% 3 3 3 3 3 10%	2772
January	1st to 10th	Night	21% 22% 9% 15% 7% 3 3 3 2 3 12%	2512
	11th to 20th	Night	20% 22% 9% 13% 7% 3 3 3 3 3 13%	2470
	21st to end	Night	18% 21% 10% 14% 8% 4 4 3 4 4 12%	2711
February	1st to 10th	Night	20% 19% 6% 12% 9% 3 4 4 4 4 16%	2340
	11th to 20th	Night	19% 15% 8% 13% 7% 3 5% 4 3 5% 18%	2273
	21st to end	Night	20% 14% 7% 13% 6% 3 4 4 3 5% 21%	1794
March	1st to 10th	Night	17% 15% 7% 9% 7% 3 4 4 5% 6% 25%	1990
	11th to 20th	Night	17% 14% 5% 6% 5% 3 5% 4 4 5% 32%	1980
	21st to end	Night	19% 14% 5% 8% 6% 3 4 4 4 4 29%	2178
April	1st to 10th	Night	18% 14% 4 5% 5% 3 4 4 5% 6% 31%	1895
	11th to 20th	Night	19% 9% 3 7% 5% 3 5% 5% 6% 6% 32%	1694
	21st to end	Night	16% 10% 3 5% 6% 3 6% 6% 5% 7% 33%	1620
May	1st to 10th	Night	19% 8% 3 6% 6% 3 5% 4 5% 6% 34%	1620
	11th to 20th	Night	15% 9% 3 7% 6% 2 5% 4 5% 8% 36%	1592
	21st to end	Night	12% 4 2 4 4 2 5% 5% 7% 10% 45%	1554
June	1st to 10th	Night	11% 5% 2 7% 6% 3 5% 5% 6% 9% 41%	1440
	11th to 20th	Night	11% 5% 3 7% 5% 3 4 5% 5% 7% 44%	1440
	21st to end	Night	13% 4 3 5% 6% 3 5% 5% 6% 9% 41%	1440
July	1st to 10th	Night	9% 6% 2 5% 4 3 5% 5% 5% 8% 49%	1443
	11th to 20th	Night	11% 5% 2 5% 5% 3 4 5% 6% 9% 45%	1620
	21st to end	Night	10% 4 2 5% 5% 4 5% 6% 7% 8% 43%	1771
August	1st to 10th	Night	9% 5% 3 5% 5% 3 5% 4 8% 9% 45%	1611
	11th to 20th	Night	11% 5% 2 6% 6% 4 5% 5% 6% 9% 43%	1598
	21st to end	Night	13% 5% 3 5% 5% 3 4 5% 6% 8% 43%	1838
September	1st to 10th	Night	14% 7% 2 4 4 2 4 5% 6% 8% 44%	1812
	11th to 20th	Night	14% 4 3 5% 5% 3 3 4 5% 7% 48%	1980
	21st to end	Night	17% 6% 2 6% 6% 4 6% 6% 5% 7% 37%	1980
October	1st to 10th	Night	19% 7% 3 6% 5% 2 3 4 5% 7% 39%	2146
	11th to 20th	Night	24% 9% 2 7% 6% 3 5% 4 5% 7% 27%	2160
	21st to end	Night	31% 11% 4 6% 5% 3 4 4 4 5% 24%	2376
November	1st to 10th	Night	19% 14% 3 7% 6% 3 4 4 4 5% 31%	2368
	11th to 20th	Night	20% 20% 4 8% 5% 3 5% 4 4 5% 22%	2622
	21st to end	Night	22% 23% 7% 7% 6% 2 4 3 4 4 19%	2660
December	1st to 10th	Night	23% 26% 11% 8% 5% 3 4 3 3 3 13%	2660
	11th to 20th	Night	19% 25% 10% 10% 5% 2 3 3 3 4 14%	3285
	21st to end	Night	25% 24% 7% 10% 6% 3 4 4 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	50% 40% 5% 5%	1651
	11th to 20th	Day	51% 39% 5% 4	1710
	21st to end	Day	56% 35% 4 3 1	1872
February	1st to 10th	Day	50% 36% 5% 6% 3	1620
	11th to 20th	Day	49% 36% 5% 7% 3	1582
	21st to end	Day	46% 36% 7% 9% 2 1	1458
March	1st to 10th	Day	39% 36% 9% 14% 2	1968
	11th to 20th	Day	36% 37% 8% 12% 6% 1	1980
	21st to end	Day	38% 37% 6% 13% 5% 1	2178
April	1st to 10th	Day	31% 37% 10% 12% 10%	2065
	11th to 20th	Day	34% 36% 7% 13% 8% 1	2230
	21st to end	Day	34% 36% 7% 14% 7% 2	2340
May	1st to 10th	Day	31% 37% 8% 14% 9% 1	2340
	11th to 20th	Day	30% 37% 6% 14% 11% 3	2305
	21st to end	Day	25% 38% 10% 17% 9% 1	2716
June	1st to 10th	Day	26% 38% 10% 16% 9% 1	2520
	11th to 20th	Day	25% 38% 10% 16% 9% 1	2520
	21st to end	Day	24% 39% 9% 18% 9% 1	2520
July	1st to 10th	Day	22% 38% 9% 18% 12% 1	2443
	11th to 20th	Day	24% 39% 9% 17% 10%	2271
	21st to end	Day	23% 40% 11% 16% 10% 1	2405
August	1st to 10th	Day	24% 37% 11% 19% 8%	2314
	11th to 20th	Day	24% 38% 12% 16% 8% 1	2303
	21st to end	Day	26% 38% 9% 15% 11% 1	2499
September	1st to 10th	Day	30% 37% 8% 15% 9% 1	2145
	11th to 20th	Day	25% 38% 11% 17% 8%	1980
	21st to end	Day	35% 38% 7% 12% 7% 1	1980
October	1st to 10th	Day	33% 38% 8% 14% 8%	1814
	11th to 20th	Day	39% 38% 10% 10% 3	1800
	21st to end	Day	42% 38% 7% 8% 4 1	1980
November	1st to 10th	Day	30% 41% 6% 13% 8% 1	1708
	11th to 20th	Day	39% 40% 6% 9% 4 2	1555
	21st to end	Day	45% 40% 5% 7% 3	1520
December	1st to 10th	Day	49% 40% 6% 5% 1	1520
	11th to 20th	Day	53% 33% 7% 6% 1	1906
	21st to end	Day	64% 26% 5% 5%	2772
January	1st to 10th	Night	51% 39% 4 4 2	2512
	11th to 20th	Night	51% 40% 4 4 1	2470
	21st to end	Night	55% 35% 4 4 1	2711
February	1st to 10th	Night	48% 36% 6% 7% 2	2340
	11th to 20th	Night	47% 37% 5% 7% 3	2275
	21st to end	Night	46% 37% 6% 7% 4	1794
March	1st to 10th	Night	40% 38% 6% 13% 4	1990
	11th to 20th	Night	36% 37% 7% 12% 8% 1	1980
	21st to end	Night	39% 36% 4 12% 7% 2	2178
April	1st to 10th	Night	34% 37% 7% 11% 9% 2	1895
	11th to 20th	Night	34% 36% 7% 12% 9% 2	1694
	21st to end	Night	34% 37% 6% 13% 7% 2	1620
May	1st to 10th	Night	32% 36% 7% 14% 8% 3	1620
	11th to 20th	Night	27% 39% 6% 13% 12% 3	1593
	21st to end	Night	20% 39% 10% 20% 10% 2	1555
June	1st to 10th	Night	25% 40% 8% 15% 11% 2	1440
	11th to 20th	Night	24% 37% 10% 14% 14% 1	1440
	21st to end	Night	26% 39% 7% 18% 9% 1	1440
July	1st to 10th	Night	23% 39% 5% 18% 13% 2	1403
	11th to 20th	Night	22% 39% 8% 17% 12% 2	1566
	21st to end	Night	21% 40% 10% 16% 12% 1	1672
August	1st to 10th	Night	26% 39% 8% 17% 10% 1	1600
	11th to 20th	Night	24% 37% 10% 19% 9% 1	1598
	21st to end	Night	24% 38% 10% 14% 12% 3	1838
September	1st to 10th	Night	27% 37% 8% 16% 10% 2	1812
	11th to 20th	Night	24% 38% 7% 18% 12% 1	1980
	21st to end	Night	34% 38% 7% 12% 8% 1	1980
October	1st to 10th	Night	32% 38% 6% 14% 9% 1	2146
	11th to 20th	Night	38% 37% 8% 11% 5% 1	2160
	21st to end	Night	41% 37% 6% 10% 4 1	2376
November	1st to 10th	Night	30% 42% 6% 14% 6% 2	2368
	11th to 20th	Night	41% 41% 5% 9% 3 2	2622
	21st to end	Night	44% 40% 5% 9% 3	2660
December	1st to 10th	Night	51% 40% 5% 4 1	2660
	11th to 20th	Night	51% 33% 10% 5% 1	3288
	21st to end	Night	64% 28% 6% 2	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% 32% 31% 7% 2	294
February	1st to 10th	Day	32% 26% 36% 6%	240
	11th to 20th	Day	31% 29% 33% 7%	240
	21st to end	Day	33% 31% 29% 7%	198
March	1st to 10th	Day	28% 24% 34% 11% 4	408
	11th to 20th	Day	27% 19% 35% 13% 4 1	420
	21st to end	Day	33% 20% 27% 17% 3	462
April	1st to 10th	Day	22% 27% 29% 15% 5%	420
	11th to 20th	Day	28% 18% 27% 18% 7% 2	412
	21st to end	Day	25% 18% 34% 16% 5% 1	420
May	1st to 10th	Day	28% 17% 31% 17% 5% 2	423
	11th to 20th	Day	20% 15% 30% 23% 11% 2	447
	21st to end	Day	15% 7% 29% 29% 15% 5%	485
June	1st to 10th	Day	16% 9% 37% 26% 10% 2	450
	11th to 20th	Day	16% 10% 30% 28% 13% 2	450
	21st to end	Day	14% 10% 31% 31% 11% 2	450
July	1st to 10th	Day	13% 4 25% 31% 19% 7%	445
	11th to 20th	Day	15% 6% 24% 33% 17% 6%	444
	21st to end	Day	10% 4 33% 33% 15% 5%	488
August	1st to 10th	Day	10% 7% 25% 32% 19% 7%	446
	11th to 20th	Day	15% 6% 23% 31% 17% 7%	439
	21st to end	Day	14% 8% 23% 31% 18% 6%	495
September	1st to 10th	Day	16% 8% 23% 28% 17% 7%	450
	11th to 20th	Day	11% 6% 25% 29% 21% 8%	450
	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% 15% 2	835
February	1st to 10th	Night	31% 22% 30% 15% 2	720
	11th to 20th	Night	27% 23% 30% 16% 3	703
	21st to end	Night	30% 22% 31% 16% 1	592
March	1st to 10th	Night	25% 20% 30% 22% 4	720
	11th to 20th	Night	23% 19% 32% 20% 5% 1	720
	21st to end	Night	26% 15% 28% 24% 7% 1	792
April	1st to 10th	Night	24% 17% 29% 24% 6%	720
	11th to 20th	Night	24% 13% 31% 23% 8% 1	630
	21st to end	Night	20% 12% 30% 30% 7% 1	540
May	1st to 10th	Night	24% 7% 25% 31% 12% 1	540
	11th to 20th	Night	20% 6% 26% 37% 10% 2	531
	21st to end	Night	13% 5% 25% 30% 24% 3	394
June	1st to 10th	Night	13% 4 30% 35% 16% 2	360
	11th to 20th	Night	14% 5% 24% 39% 18% 1	360
	21st to end	Night	13% 5% 27% 34% 21%	360
July	1st to 10th	Night	9% 5% 18% 40% 23% 5%	353
	11th to 20th	Night	11% 3 23% 33% 26% 4	522
	21st to end	Night	11% 3 21% 37% 26% 3	591
August	1st to 10th	Night	10% 3 17% 40% 25% 5%	537
	11th to 20th	Night	13% 2 16% 33% 30% 5%	534
	21st to end	Night	15% 5% 22% 28% 27% 4	650
September	1st to 10th	Night	17% 6% 18% 29% 25% 5%	720
	11th to 20th	Night	15% 5% 17% 33% 25% 5%	720
	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 2024-01-28 05:26:38. Version ac07

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