Cedarville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cedarville 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% 8% 2 6% 4 4 4 3 5% 7% 39%	101205
	Night	18% 9% 3 7% 4 4 4 3 5% 6% 38%	97967
Transparency	Day	45% 4 12% 23% 14% 2	104772
	Night	48% 4 11% 22% 14% 2	102489
Seeing	Day	19% 5% 22% 30% 18% 5%	15215
	Night	21% 8% 26% 30% 13% 2	24065

By Month

Percentage Cloud Cover NE (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	16% 9% 3 6% 3 3 4 3 4 5% 45%	2517
	11th to 20th	Day	19% 10% 2 6% 4 3 3 4 5% 5% 40%	2520
	21st to end	Day	21% 12% 3 9% 3 3 4 3 3 4 33%	2811
February	1st to 10th	Day	19% 9% 4 7% 4 5% 4 3 4 5% 36%	1800
	11th to 20th	Day	14% 8% 2 6% 4 4 4 3 4 6% 43%	1848
	21st to end	Day	18% 10% 3 5% 4 3 5% 3 4 6% 37%	1570
March	1st to 10th	Day	25% 15% 4 6% 4 3 3 2 3 5% 30%	3116
	11th to 20th	Day	12% 7% 3 7% 4 4 4 4 5% 7% 45%	3402
	21st to end	Day	23% 11% 2 7% 4 4 4 2 4 4 35%	3932
April	1st to 10th	Day	19% 10% 3 6% 3 3 4 3 4 6% 39%	2280
	11th to 20th	Day	18% 8% 2 7% 4 5% 4 3 4 6% 40%	2295
	21st to end	Day	19% 7% 2 6% 4 4 4 4 5% 6% 39%	2470
May	1st to 10th	Day	25% 12% 3 8% 4 4 3 3 5% 6% 27%	4106
	11th to 20th	Day	23% 12% 3 6% 4 3 3 2 5% 7% 32%	4081
	21st to end	Day	15% 6% 2 5% 3 4 4 3 5% 8% 44%	4741
June	1st to 10th	Day	19% 8% 2 5% 4 4 4 4 7% 8% 35%	2660
	11th to 20th	Day	14% 7% 2 5% 4 4 5% 4 6% 8% 39%	2660
	21st to end	Day	14% 7% 2 6% 4 4 5% 4 6% 9% 40%	2660
July	1st to 10th	Day	12% 9% 3 6% 5% 5% 5% 4 7% 9% 36%	4440
	11th to 20th	Day	12% 8% 2 7% 5% 5% 4 4 7% 9% 38%	4440
	21st to end	Day	19% 7% 2 6% 5% 4 4 4 5% 8% 35%	4731
August	1st to 10th	Day	16% 7% 3 7% 5% 5% 5% 4 6% 7% 34%	4105
	11th to 20th	Day	12% 7% 3 7% 4 5% 5% 4 6% 8% 40%	4045
	21st to end	Day	8% 4 1 5% 3 4 5% 4 7% 11% 47%	4190
September	1st to 10th	Day	14% 6% 2 6% 4 4 4 3 5% 6% 47%	2237
	11th to 20th	Day	15% 5% 2 5% 3 3 3 2 4 7% 50%	2090
	21st to end	Day	20% 6% 2 6% 4 3 4 3 5% 7% 41%	2090
October	1st to 10th	Day	21% 7% 1 5% 4 3 4 3 4 6% 43%	2090
	11th to 20th	Day	15% 6% 2 5% 3 3 4 3 5% 7% 48%	1889
	21st to end	Day	19% 6% 2 5% 4 3 3 3 5% 6% 44%	1881
November	1st to 10th	Day	17% 7% 3 5% 4 4 3 2 5% 5% 45%	1761
	11th to 20th	Day	17% 8% 1 4 4 3 3 3 6% 7% 43%	1710
	21st to end	Day	18% 6% 2 5% 4 3 4 4 6% 6% 42%	1710
December	1st to 10th	Day	19% 9% 3 6% 4 4 4 3 5% 6% 39%	1649
	11th to 20th	Day	20% 10% 2 6% 4 4 3 3 4 6% 39%	1906
	21st to end	Day	21% 11% 3 8% 5% 4 4 3 5% 5% 32%	2772
January	1st to 10th	Night	17% 8% 2 4 3 3 3 3 4 5% 48%	4429
	11th to 20th	Night	16% 12% 4 8% 4 3 3 2 4 5% 40%	4440
	21st to end	Night	23% 13% 5% 10% 5% 4 3 3 4 4 29%	4843
February	1st to 10th	Night	17% 10% 3 8% 4 4 4 3 4 6% 38%	2378
	11th to 20th	Night	18% 10% 3 6% 4 4 3 3 5% 5% 39%	2218
	21st to end	Night	17% 8% 2 6% 5% 4 3 3 4 5% 41%	1884
March	1st to 10th	Night	31% 11% 2 4 3 2 3 3 3 5% 32%	3724
	11th to 20th	Night	10% 11% 4 7% 5% 4 4 4 5% 6% 39%	3557
	21st to end	Night	25% 10% 3 7% 5% 4 5% 3 3 4 32%	3695
April	1st to 10th	Night	19% 9% 3 7% 5% 4 4 3 4 6% 37%	1900
	11th to 20th	Night	18% 9% 2 5% 5% 4 4 3 6% 6% 37%	1833
	21st to end	Night	19% 8% 3 6% 5% 4 5% 3 5% 6% 37%	1710
May	1st to 10th	Night	24% 11% 4 10% 4 4 4 3 5% 6% 24%	2834
	11th to 20th	Night	24% 13% 3 8% 4 4 5% 4 6% 7% 24%	2813
	21st to end	Night	16% 8% 3 8% 4 4 4 4 6% 8% 35%	2848
June	1st to 10th	Night	17% 8% 3 7% 5% 5% 4 4 5% 8% 34%	1520
	11th to 20th	Night	18% 8% 2 5% 4 4 5% 3 5% 8% 38%	1520
	21st to end	Night	17% 9% 3 6% 4 4 4 3 6% 9% 35%	1520
July	1st to 10th	Night	13% 13% 4 9% 5% 4 4 4 6% 8% 31%	2520
	11th to 20th	Night	13% 11% 3 6% 4 4 5% 4 6% 9% 35%	2520
	21st to end	Night	17% 9% 3 8% 5% 4 5% 4 6% 7% 31%	2791
August	1st to 10th	Night	19% 10% 3 6% 4 5% 5% 4 7% 6% 29%	2825
	11th to 20th	Night	9% 9% 3 7% 5% 5% 6% 4 7% 8% 37%	2782
	21st to end	Night	8% 5% 2 5% 3 3 4 4 5% 7% 54%	3462
September	1st to 10th	Night	13% 6% 2 6% 6% 3 4 4 4 6% 46%	1943
	11th to 20th	Night	14% 6% 2 5% 3 3 3 2 5% 6% 50%	2090
	21st to end	Night	19% 7% 2 7% 4 4 4 3 5% 5% 40%	2090
October	1st to 10th	Night	21% 7% 3 6% 4 4 3 3 4 5% 40%	2090
	11th to 20th	Night	15% 5% 2 5% 4 3 4 3 5% 6% 48%	2288
	21st to end	Night	19% 8% 2 6% 4 4 4 3 5% 6% 39%	2717
November	1st to 10th	Night	16% 6% 2 6% 4 4 4 3 4 5% 45%	2537
	11th to 20th	Night	17% 8% 3 5% 4 4 3 3 5% 5% 44%	2477
	21st to end	Night	15% 7% 2 5% 3 3 4 3 5% 6% 45%	2470
December	1st to 10th	Night	20% 8% 3 7% 4 4 3 3 4 5% 39%	2527
	11th to 20th	Night	17% 9% 2 6% 4 4 4 3 5% 6% 40%	3288
	21st to end	Night	19% 12% 4 8% 4 3 4 3 4 5% 35%	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	45% 2 8% 31% 13% 1	2518
	11th to 20th	Day	48% 3 10% 25% 10% 2	2520
	21st to end	Day	60% 2 9% 20% 8% 1	2811
February	1st to 10th	Day	53% 2 11% 18% 13% 2	1800
	11th to 20th	Day	46% 4 11% 23% 14% 2	1857
	21st to end	Day	50% 3 11% 20% 14% 2	1570
March	1st to 10th	Day	61% 2 11% 14% 11% 2	3119
	11th to 20th	Day	41% 3 14% 26% 14% 2	3402
	21st to end	Day	54% 2 6% 17% 15% 6%	3932
April	1st to 10th	Day	47% 3 9% 20% 18% 4	2280
	11th to 20th	Day	44% 2 10% 25% 16% 3	2295
	21st to end	Day	45% 3 9% 22% 17% 4	2470
May	1st to 10th	Day	61% 3 10% 16% 9% 1	4120
	11th to 20th	Day	54% 2 14% 18% 11% 1	4085
	21st to end	Day	39% 3 12% 25% 20% 1	4741
June	1st to 10th	Day	46% 5% 13% 24% 12%	2660
	11th to 20th	Day	41% 4 14% 25% 14% 1	2660
	21st to end	Day	41% 5% 16% 24% 13% 1	2660
July	1st to 10th	Day	44% 7% 14% 20% 14% 1	4370
	11th to 20th	Day	37% 6% 19% 24% 13% 1	4365
	21st to end	Day	44% 6% 14% 23% 11% 2	4580
August	1st to 10th	Day	46% 6% 17% 22% 8%	4092
	11th to 20th	Day	41% 7% 16% 28% 9%	4084
	21st to end	Day	28% 7% 17% 28% 19% 1	4190
September	1st to 10th	Day	38% 4 10% 26% 21% 1	2237
	11th to 20th	Day	35% 3 9% 29% 21% 3	2090
	21st to end	Day	44% 4 8% 23% 19% 2	2090
October	1st to 10th	Day	38% 5% 12% 28% 16% 2	3480
	11th to 20th	Day	32% 3 8% 30% 25% 2	3105
	21st to end	Day	30% 4 13% 34% 16% 2	3081
November	1st to 10th	Day	42% 4 13% 24% 15% 2	1761
	11th to 20th	Day	44% 4 10% 22% 18% 2	1710
	21st to end	Day	43% 5% 12% 26% 12% 2	1710
December	1st to 10th	Day	50% 3 13% 17% 15% 1	1649
	11th to 20th	Day	52% 3 13% 16% 13% 2	1906
	21st to end	Day	58% 2 12% 19% 9% 1	2772
January	1st to 10th	Night	44% 2 9% 31% 11% 2	4429
	11th to 20th	Night	51% 3 10% 23% 12% 2	4440
	21st to end	Night	65% 2 7% 17% 9% 1	4843
February	1st to 10th	Night	51% 4 11% 21% 11% 1	2378
	11th to 20th	Night	50% 4 8% 21% 15% 2	2220
	21st to end	Night	47% 3 8% 25% 14% 3	1884
March	1st to 10th	Night	58% 2 9% 18% 11% 2	3734
	11th to 20th	Night	47% 3 11% 20% 17% 2	3558
	21st to end	Night	59% 2 5% 13% 16% 6%	3695
April	1st to 10th	Night	50% 2 8% 19% 16% 3	1900
	11th to 20th	Night	48% 2 8% 21% 18% 3	1833
	21st to end	Night	50% 3 8% 20% 16% 3	1710
May	1st to 10th	Night	61% 2 11% 17% 7% 1	2840
	11th to 20th	Night	60% 3 13% 15% 7% 2	2814
	21st to end	Night	47% 3 12% 23% 15% 1	2849
June	1st to 10th	Night	49% 5% 12% 22% 11% 1	1520
	11th to 20th	Night	44% 3 10% 26% 15% 1	1520
	21st to end	Night	45% 5% 14% 23% 13%	1520
July	1st to 10th	Night	48% 7% 11% 19% 15%	2480
	11th to 20th	Night	42% 7% 16% 23% 11% 1	2472
	21st to end	Night	51% 5% 11% 20% 11% 2	2702
August	1st to 10th	Night	50% 7% 14% 18% 9% 1	2813
	11th to 20th	Night	40% 8% 17% 26% 8%	2809
	21st to end	Night	27% 6% 15% 28% 22% 1	3462
September	1st to 10th	Night	38% 4 11% 24% 21% 1	1943
	11th to 20th	Night	35% 3 10% 26% 23% 2	2090
	21st to end	Night	44% 5% 6% 22% 20% 3	2090
October	1st to 10th	Night	43% 5% 10% 27% 13% 2	3480
	11th to 20th	Night	29% 3 8% 27% 31% 3	3811
	21st to end	Night	35% 3 10% 29% 21% 2	4467
November	1st to 10th	Night	42% 4 12% 23% 16% 3	2537
	11th to 20th	Night	46% 3 10% 21% 17% 3	2477
	21st to end	Night	42% 3 13% 28% 12% 2	2470
December	1st to 10th	Night	52% 3 13% 20% 12% 1	2527
	11th to 20th	Night	49% 3 12% 18% 16% 2	3288
	21st to end	Night	56% 3 10% 21% 10%	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	26% 10% 33% 22% 8% 1	180
	11th to 20th	Day	22% 13% 33% 25% 7%	180
	21st to end	Day	20% 7% 39% 26% 5% 2	224
February	1st to 10th	Day	25% 8% 33% 28% 5%	412
	11th to 20th	Day	20% 12% 43% 21% 4	456
	21st to end	Day	22% 12% 31% 28% 7% 1	382
March	1st to 10th	Day	23% 9% 33% 28% 6%	460
	11th to 20th	Day	17% 10% 36% 29% 8%	460
	21st to end	Day	22% 8% 32% 26% 8% 3	506
April	1st to 10th	Day	24% 8% 28% 28% 9% 3	460
	11th to 20th	Day	22% 7% 27% 34% 10%	452
	21st to end	Day	23% 3 22% 35% 14% 2	460
May	1st to 10th	Day	29% 4 21% 33% 11% 2	463
	11th to 20th	Day	19% 3 22% 36% 15% 5%	487
	21st to end	Day	16% 2 17% 34% 24% 7%	529
June	1st to 10th	Day	19% 2 13% 36% 25% 6%	490
	11th to 20th	Day	15% 2 16% 37% 24% 6%	490
	21st to end	Day	14% 2 14% 35% 28% 6%	490
July	1st to 10th	Day	14% 3 9% 32% 33% 10%	485
	11th to 20th	Day	11% 2 9% 31% 37% 10%	484
	21st to end	Day	13% 2 11% 36% 33% 6%	532
August	1st to 10th	Day	13% 1 8% 41% 31% 7%	486
	11th to 20th	Day	15% 2 8% 32% 32% 11%	479
	21st to end	Day	12% 3 11% 30% 30% 14%	539
September	1st to 10th	Day	16% 1 14% 32% 26% 11%	490
	11th to 20th	Day	18% 2 15% 27% 25% 12%	490
	21st to end	Day	23% 3 20% 29% 19% 7%	490
October	1st to 10th	Day	24% 3 17% 27% 21% 7%	490
	11th to 20th	Day	17% 6% 26% 27% 19% 5%	418
	21st to end	Day	23% 4 30% 27% 12% 4	429
November	1st to 10th	Day	16% 8% 26% 31% 16% 3	395
	11th to 20th	Day	23% 10% 32% 24% 11%	370
	21st to end	Day	21% 10% 29% 28% 10% 2	370
December	1st to 10th	Day	23% 8% 34% 28% 8%	309
	11th to 20th	Day	26% 12% 37% 22% 4 1	180
	21st to end	Day	25% 7% 39% 20% 7% 2	198
January	1st to 10th	Night	22% 13% 40% 21% 4	760
	11th to 20th	Night	26% 15% 35% 21% 3	760
	21st to end	Night	23% 13% 37% 22% 5% 1	836
February	1st to 10th	Night	23% 13% 34% 28% 2	760
	11th to 20th	Night	24% 13% 42% 19% 2	743
	21st to end	Night	23% 13% 36% 24% 5%	628
March	1st to 10th	Night	23% 13% 34% 24% 6%	760
	11th to 20th	Night	19% 11% 35% 27% 7% 1	760
	21st to end	Night	24% 9% 31% 26% 9% 1	836
April	1st to 10th	Night	24% 7% 31% 30% 7% 1	760
	11th to 20th	Night	23% 5% 30% 34% 8%	709
	21st to end	Night	22% 4 26% 34% 14% 1	570
May	1st to 10th	Night	27% 4 23% 33% 12% 2	570
	11th to 20th	Night	24% 3 26% 34% 10% 2	562
	21st to end	Night	22% 3 13% 43% 18% 2	482
June	1st to 10th	Night	23% 2 17% 37% 19% 3	380
	11th to 20th	Night	24% 1 13% 43% 18% 2	380
	21st to end	Night	20% 3 11% 44% 21% 1	380
July	1st to 10th	Night	12% 3 12% 45% 26% 2	370
	11th to 20th	Night	15% 3 8% 42% 30% 2	368
	21st to end	Night	16% 2 9% 43% 28% 2	444
August	1st to 10th	Night	11% 2 10% 46% 28% 3	568
	11th to 20th	Night	13% 3 10% 43% 28% 3	562
	21st to end	Night	13% 2 10% 38% 31% 6%	822
September	1st to 10th	Night	15% 1 15% 36% 30% 3	760
	11th to 20th	Night	16% 3 16% 33% 25% 8%	760
	21st to end	Night	21% 3 17% 32% 23% 4	760
October	1st to 10th	Night	23% 7% 19% 28% 19% 4	760
	11th to 20th	Night	19% 7% 29% 28% 16% 3	760
	21st to end	Night	24% 7% 31% 28% 10% 1	836
November	1st to 10th	Night	20% 6% 28% 31% 13% 2	780
	11th to 20th	Night	23% 13% 31% 25% 9% 1	763
	21st to end	Night	19% 16% 29% 27% 8% 1	760
December	1st to 10th	Night	25% 12% 34% 22% 6% 1	760
	11th to 20th	Night	24% 16% 35% 21% 4	760
	21st to end	Night	23% 11% 38% 23% 4	836

Page generated at 2024-11-08 06:44:47. Version ac07

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