Old LeBoeuf Cemetery
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Old LeBoeuf Cemetery clear sky chart from 2005-11-06 to 2025-02-21.

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% 13% 5% 10% 5% 4 4 3 5% 6% 27%	108735
	Night	17% 15% 6% 11% 5% 4 4 3 4 5% 26%	109855
Transparency	Day	56% 6% 11% 18% 9% 1	112377
	Night	59% 5% 10% 16% 9% 1	114352
Seeing	Day	25% 18% 29% 18% 8% 2	14852
	Night	25% 16% 28% 21% 9% 1	24564

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	14% 22% 12% 28% 5% 3 3 2 2 3 7%	3823
	11th to 20th	Day	11% 24% 10% 23% 8% 7% 2 2 2 3 9%	4060
	21st to end	Day	20% 18% 9% 18% 8% 5% 4 2 3 3 11%	4466
February	1st to 10th	Day	16% 20% 6% 17% 10% 4 3 2 3 3 16%	1800
	11th to 20th	Day	15% 18% 9% 16% 9% 4 3 3 3 4 15%	1753
	21st to end	Day	17% 20% 4 13% 6% 4 4 3 4 6% 20%	1530
March	1st to 10th	Day	21% 13% 8% 9% 4 3 4 3 5% 6% 25%	3435
	11th to 20th	Day	11% 22% 8% 10% 4 3 4 2 4 5% 28%	3480
	21st to end	Day	21% 14% 4 12% 4 3 3 3 4 5% 28%	3815
April	1st to 10th	Day	17% 16% 4 7% 4 5% 4 3 5% 7% 29%	2206
	11th to 20th	Day	21% 14% 2 6% 4 3 4 4 5% 5% 32%	2314
	21st to end	Day	21% 13% 3 7% 4 4 3 3 4 5% 33%	2470
May	1st to 10th	Day	21% 9% 3 8% 6% 4 5% 3 5% 6% 31%	4082
	11th to 20th	Day	19% 10% 3 8% 4 4 4 4 6% 8% 29%	4158
	21st to end	Day	13% 5% 2 7% 5% 5% 5% 4 5% 8% 41%	4823
June	1st to 10th	Day	17% 7% 3 7% 5% 4 5% 4 6% 8% 36%	2660
	11th to 20th	Day	15% 7% 3 7% 5% 5% 4 4 6% 8% 37%	2660
	21st to end	Day	17% 6% 2 6% 4 5% 5% 5% 6% 8% 37%	2660
July	1st to 10th	Day	11% 5% 2 7% 5% 5% 6% 4 7% 10% 39%	4440
	11th to 20th	Day	13% 6% 2 6% 4 4 5% 4 6% 9% 41%	4192
	21st to end	Day	11% 6% 2 7% 5% 5% 5% 5% 6% 8% 39%	4466
August	1st to 10th	Day	16% 7% 2 8% 5% 5% 5% 4 6% 9% 32%	4104
	11th to 20th	Day	16% 8% 3 7% 5% 5% 5% 5% 8% 9% 29%	4044
	21st to end	Day	12% 6% 2 7% 4 5% 5% 4 7% 10% 37%	4346
September	1st to 10th	Day	18% 7% 3 6% 4 4 4 4 6% 7% 37%	2280
	11th to 20th	Day	13% 6% 2 6% 5% 4 5% 4 6% 8% 41%	2116
	21st to end	Day	21% 9% 4 7% 5% 4 4 4 5% 7% 32%	2081
October	1st to 10th	Day	19% 8% 3 6% 4 5% 5% 3 6% 7% 34%	1900
	11th to 20th	Day	23% 10% 3 9% 4 5% 4 3 5% 6% 28%	1900
	21st to end	Day	25% 14% 3 7% 5% 4 4 3 5% 6% 23%	2090
November	1st to 10th	Day	15% 15% 4 7% 5% 4 5% 4 5% 6% 31%	1831
	11th to 20th	Day	18% 22% 4 9% 4 4 3 3 5% 5% 23%	1600
	21st to end	Day	20% 27% 6% 7% 6% 4 5% 2 4 5% 14%	1600
December	1st to 10th	Day	19% 29% 16% 13% 4 3 2 3 2 2 7%	2600
	11th to 20th	Day	21% 26% 9% 13% 5% 3 3 2 4 4 12%	2990
	21st to end	Day	25% 24% 9% 13% 6% 3 3 2 2 3 10%	3960
January	1st to 10th	Night	14% 20% 11% 30% 5% 3 2 2 2 2 8%	6119
	11th to 20th	Night	11% 21% 12% 23% 9% 5% 4 2 3 3 8%	5900
	21st to end	Night	20% 19% 9% 18% 6% 3 5% 2 3 3 12%	6490
February	1st to 10th	Night	19% 20% 6% 14% 8% 4 4 3 3 3 16%	2600
	11th to 20th	Night	16% 17% 7% 16% 9% 5% 4 3 4 4 16%	2533
	21st to end	Night	19% 15% 6% 15% 7% 4 3 3 3 4 21%	1920
March	1st to 10th	Night	21% 16% 4 9% 5% 3 3 2 4 4 28%	3418
	11th to 20th	Night	17% 16% 9% 9% 4 3 3 3 4 5% 27%	3480
	21st to end	Night	17% 13% 5% 9% 5% 3 3 3 4 3 34%	3817
April	1st to 10th	Night	18% 18% 4 7% 4 4 4 3 4 6% 29%	1973
	11th to 20th	Night	18% 12% 2 7% 4 4 4 4 4 6% 33%	1830
	21st to end	Night	15% 12% 3 7% 5% 5% 5% 4 5% 6% 34%	1710
May	1st to 10th	Night	26% 10% 2 6% 4 4 4 2 5% 6% 32%	2813
	11th to 20th	Night	16% 9% 3 7% 5% 5% 4 3 5% 7% 36%	2731
	21st to end	Night	14% 5% 2 4 3 4 3 4 7% 10% 44%	2732
June	1st to 10th	Night	12% 6% 2 6% 6% 4 4 4 7% 8% 40%	1520
	11th to 20th	Night	12% 6% 3 7% 5% 4 4 4 6% 7% 42%	1520
	21st to end	Night	13% 6% 2 6% 5% 4 4 4 6% 9% 40%	1520
July	1st to 10th	Night	13% 8% 3 7% 4 4 3 3 5% 9% 41%	2520
	11th to 20th	Night	13% 6% 2 5% 5% 4 4 3 5% 9% 44%	2764
	21st to end	Night	10% 6% 2 6% 4 4 5% 5% 6% 8% 44%	3087
August	1st to 10th	Night	12% 9% 3 8% 5% 5% 4 4 6% 7% 38%	2825
	11th to 20th	Night	16% 7% 3 6% 5% 4 4 4 5% 6% 38%	2785
	21st to end	Night	9% 6% 2 7% 5% 5% 4 4 7% 9% 43%	3276
September	1st to 10th	Night	13% 7% 3 5% 4 4 4 4 5% 7% 43%	1900
	11th to 20th	Night	12% 6% 2 5% 4 3 4 3 5% 6% 49%	2061
	21st to end	Night	18% 8% 3 7% 5% 4 5% 3 5% 7% 34%	2099
October	1st to 10th	Night	18% 7% 2 6% 4 4 3 3 5% 7% 39%	2280
	11th to 20th	Night	22% 10% 3 8% 4 4 4 3 5% 6% 29%	2280
	21st to end	Night	28% 11% 2 6% 4 4 4 3 5% 5% 28%	2508
November	1st to 10th	Night	16% 15% 3 7% 5% 4 4 3 6% 6% 33%	2463
	11th to 20th	Night	20% 21% 4 8% 4 4 4 3 5% 6% 22%	2800
	21st to end	Night	20% 24% 6% 9% 4 3 4 3 4 5% 19%	2800
December	1st to 10th	Night	17% 24% 14% 12% 4 4 4 3 3 4 12%	4580
	11th to 20th	Night	20% 25% 10% 12% 5% 3 3 2 3 4 14%	5205
	21st to end	Night	22% 23% 7% 12% 6% 4 4 2 4 4 12%	6996

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	85% 3 5% 5% 1	3824
	11th to 20th	Day	84% 2 6% 7% 1	4060
	21st to end	Day	81% 2 7% 7% 3	4466
February	1st to 10th	Day	76% 3 7% 9% 4	1800
	11th to 20th	Day	74% 5% 7% 10% 5%	1762
	21st to end	Day	65% 5% 10% 13% 4 2	1530
March	1st to 10th	Day	59% 6% 9% 22% 4	3435
	11th to 20th	Day	59% 6% 16% 14% 5% 1	3480
	21st to end	Day	60% 5% 7% 18% 10% 1	3815
April	1st to 10th	Day	56% 5% 12% 16% 11%	2206
	11th to 20th	Day	53% 6% 10% 19% 10% 2	2314
	21st to end	Day	53% 5% 10% 18% 11% 2	2470
May	1st to 10th	Day	53% 5% 8% 23% 9% 1	4120
	11th to 20th	Day	50% 8% 12% 20% 8% 1	4162
	21st to end	Day	39% 8% 14% 21% 15% 4	4837
June	1st to 10th	Day	45% 7% 13% 23% 12% 1	2660
	11th to 20th	Day	43% 8% 13% 21% 13% 1	2660
	21st to end	Day	41% 8% 13% 25% 13% 1	2660
July	1st to 10th	Day	38% 7% 13% 23% 16% 2	4370
	11th to 20th	Day	39% 6% 13% 24% 17% 1	4120
	21st to end	Day	40% 8% 13% 22% 16% 1	4324
August	1st to 10th	Day	46% 8% 14% 21% 10%	4091
	11th to 20th	Day	46% 9% 14% 24% 6% 1	4083
	21st to end	Day	39% 8% 11% 28% 12% 1	4346
September	1st to 10th	Day	45% 6% 13% 21% 13% 2	2280
	11th to 20th	Day	40% 8% 12% 24% 16%	2116
	21st to end	Day	51% 7% 11% 21% 10% 1	2081
October	1st to 10th	Day	40% 7% 14% 22% 16% 1	3160
	11th to 20th	Day	49% 5% 13% 17% 12% 4	3140
	21st to end	Day	49% 5% 15% 22% 8% 1	3428
November	1st to 10th	Day	54% 6% 10% 18% 11% 2	1831
	11th to 20th	Day	63% 5% 10% 13% 6% 2	1600
	21st to end	Day	73% 6% 8% 8% 4 1	1600
December	1st to 10th	Day	85% 4 5% 5% 1	2600
	11th to 20th	Day	79% 3 7% 10% 1	2986
	21st to end	Day	83% 3 7% 6% 1	3960
January	1st to 10th	Night	85% 3 5% 6% 1	6119
	11th to 20th	Night	83% 3 7% 6% 1	5900
	21st to end	Night	79% 3 7% 7% 3	6490
February	1st to 10th	Night	74% 5% 8% 11% 3	2600
	11th to 20th	Night	73% 4 9% 11% 3	2535
	21st to end	Night	68% 4 9% 11% 7% 1	1920
March	1st to 10th	Night	60% 4 11% 19% 6%	3418
	11th to 20th	Night	60% 5% 12% 16% 6% 1	3480
	21st to end	Night	54% 6% 9% 17% 13% 2	3817
April	1st to 10th	Night	57% 5% 11% 15% 11% 1	1973
	11th to 20th	Night	51% 6% 10% 18% 12% 2	1830
	21st to end	Night	49% 7% 12% 19% 10% 3	1710
May	1st to 10th	Night	53% 5% 10% 18% 10% 3	2840
	11th to 20th	Night	46% 8% 13% 21% 10% 2	2732
	21st to end	Night	33% 9% 13% 27% 15% 3	2739
June	1st to 10th	Night	40% 8% 13% 23% 14% 2	1520
	11th to 20th	Night	40% 7% 13% 23% 15% 2	1520
	21st to end	Night	40% 9% 13% 22% 16%	1520
July	1st to 10th	Night	42% 6% 11% 21% 17% 3	2480
	11th to 20th	Night	36% 7% 12% 26% 16% 2	2713
	21st to end	Night	36% 8% 13% 21% 20% 1	2988
August	1st to 10th	Night	43% 6% 12% 27% 11% 1	2814
	11th to 20th	Night	44% 7% 14% 26% 7% 1	2812
	21st to end	Night	35% 8% 15% 29% 11% 1	3276
September	1st to 10th	Night	38% 8% 12% 25% 14% 2	1900
	11th to 20th	Night	35% 6% 13% 25% 20% 1	2061
	21st to end	Night	48% 7% 12% 19% 13% 1	2099
October	1st to 10th	Night	40% 7% 9% 22% 21% 1	3800
	11th to 20th	Night	48% 6% 12% 15% 15% 4	3779
	21st to end	Night	44% 4 15% 23% 13% 1	4120
November	1st to 10th	Night	51% 6% 12% 20% 9% 2	2463
	11th to 20th	Night	64% 6% 9% 13% 6% 3	2800
	21st to end	Night	69% 5% 10% 12% 3 1	2800
December	1st to 10th	Night	77% 4 10% 7% 1	4580
	11th to 20th	Night	77% 3 8% 10% 2	5208
	21st to end	Night	77% 5% 8% 9% 1	6996

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	31% 30% 28% 8% 2	248
	11th to 20th	Day	34% 34% 24% 5% 3	300
	21st to end	Day	34% 32% 28% 5% 2	330
February	1st to 10th	Day	37% 25% 32% 6%	300
	11th to 20th	Day	40% 26% 28% 6% 1	300
	21st to end	Day	43% 25% 26% 5%	242
March	1st to 10th	Day	30% 27% 31% 8% 3	460
	11th to 20th	Day	32% 23% 32% 9% 2 1	460
	21st to end	Day	36% 23% 25% 12% 2	506
April	1st to 10th	Day	27% 27% 28% 13% 3 1	460
	11th to 20th	Day	32% 23% 23% 14% 6% 2	452
	21st to end	Day	28% 22% 32% 13% 4 1	460
May	1st to 10th	Day	30% 18% 29% 16% 5% 2	463
	11th to 20th	Day	23% 20% 25% 22% 9% 2	487
	21st to end	Day	17% 10% 33% 25% 11% 4	529
June	1st to 10th	Day	20% 16% 31% 24% 7% 3	490
	11th to 20th	Day	20% 11% 29% 26% 12% 2	490
	21st to end	Day	19% 12% 35% 23% 9% 2	490
July	1st to 10th	Day	11% 9% 28% 29% 16% 6%	485
	11th to 20th	Day	15% 11% 31% 24% 15% 5%	484
	21st to end	Day	11% 10% 36% 26% 14% 3	532
August	1st to 10th	Day	13% 9% 28% 29% 15% 7%	486
	11th to 20th	Day	18% 8% 27% 27% 14% 6%	479
	21st to end	Day	12% 9% 28% 28% 17% 5%	539
September	1st to 10th	Day	18% 11% 25% 26% 15% 5%	490
	11th to 20th	Day	12% 7% 26% 29% 19% 8%	490
	21st to end	Day	24% 14% 28% 19% 11% 4	490
October	1st to 10th	Day	21% 17% 26% 20% 13% 2	490
	11th to 20th	Day	27% 20% 31% 14% 6% 2	490
	21st to end	Day	36% 21% 28% 13% 2	539
November	1st to 10th	Day	31% 20% 28% 14% 5% 1	371
	11th to 20th	Day	39% 22% 29% 9% 3	200
	21st to end	Day	35% 25% 34% 7%	200
December	1st to 10th	Day	40% 29% 24% 5% 2 1	200
	11th to 20th	Day	42% 25% 27% 6% 2	200
	21st to end	Day	36% 24% 33% 6% 1	220
January	1st to 10th	Night	32% 29% 28% 10% 2	800
	11th to 20th	Night	34% 25% 28% 12% 1	800
	21st to end	Night	26% 26% 32% 14% 2	880
February	1st to 10th	Night	34% 24% 28% 14%	800
	11th to 20th	Night	30% 26% 32% 12% 1	783
	21st to end	Night	32% 23% 31% 12% 2	629
March	1st to 10th	Night	27% 22% 33% 15% 3	760
	11th to 20th	Night	29% 21% 28% 18% 3	760
	21st to end	Night	26% 19% 31% 18% 4	836
April	1st to 10th	Night	27% 19% 32% 17% 5%	760
	11th to 20th	Night	28% 14% 31% 19% 7% 1	706
	21st to end	Night	22% 14% 33% 25% 5% 1	570
May	1st to 10th	Night	25% 11% 28% 27% 9% 1	570
	11th to 20th	Night	18% 10% 32% 33% 7% 1	519
	21st to end	Night	13% 8% 31% 29% 18% 2	411
June	1st to 10th	Night	14% 6% 34% 33% 13%	380
	11th to 20th	Night	12% 8% 30% 38% 11%	380
	21st to end	Night	13% 7% 33% 33% 13% 1	380
July	1st to 10th	Night	11% 6% 21% 41% 17% 4	370
	11th to 20th	Night	11% 5% 24% 34% 24% 3	505
	21st to end	Night	12% 4 21% 38% 24% 1	624
August	1st to 10th	Night	12% 5% 19% 39% 24% 2	567
	11th to 20th	Night	13% 5% 20% 33% 27% 3	564
	21st to end	Night	14% 5% 22% 31% 24% 3	714
September	1st to 10th	Night	17% 8% 18% 33% 21% 3	760
	11th to 20th	Night	13% 7% 20% 33% 23% 4	760
	21st to end	Night	23% 12% 22% 26% 14% 3	760
October	1st to 10th	Night	21% 9% 29% 23% 16% 2	760
	11th to 20th	Night	28% 16% 27% 20% 8% 1	760
	21st to end	Night	35% 15% 30% 17% 3	836
November	1st to 10th	Night	24% 17% 30% 22% 7%	780
	11th to 20th	Night	35% 21% 27% 13% 4 1	800
	21st to end	Night	35% 22% 28% 12% 3	800
December	1st to 10th	Night	37% 24% 28% 9% 3	800
	11th to 20th	Night	32% 29% 26% 11% 2	800
	21st to end	Night	34% 23% 30% 12% 1	880

Page generated at 2025-02-18 03:26:26. Version ac07

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