Lamping Homestead
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lamping Homestead clear sky chart from 2005-11-06 to 2025-07-21.

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	16% 10% 3 8% 5% 4 5% 4 6% 7% 32%	119630
	Night	16% 11% 4 9% 5% 4 4 3 5% 6% 33%	119372
Transparency	Day	48% 6% 11% 21% 12% 2	123316
	Night	49% 6% 10% 20% 12% 2	123823
Seeing	Day	23% 13% 26% 21% 12% 4	15701
	Night	21% 11% 25% 28% 13% 2	25954

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	17% 20% 7% 18% 5% 3 3 2 3 4 16%	4056
	11th to 20th	Day	14% 21% 8% 13% 9% 5% 4 2 3 4 18%	4060
	21st to end	Day	20% 18% 5% 11% 7% 6% 4 3 4 4 19%	4466
February	1st to 10th	Day	22% 14% 5% 8% 6% 4 4 3 4 5% 26%	1800
	11th to 20th	Day	18% 14% 5% 12% 5% 4 3 3 5% 6% 25%	1823
	21st to end	Day	20% 14% 5% 9% 4 3 3 3 4 5% 30%	1650
March	1st to 10th	Day	17% 15% 4 8% 4 4 3 3 4 5% 31%	4903
	11th to 20th	Day	13% 8% 3 6% 4 5% 5% 3 5% 7% 42%	4980
	21st to end	Day	19% 9% 3 8% 5% 5% 5% 3 6% 6% 31%	5465
April	1st to 10th	Day	16% 13% 4 8% 6% 5% 4 3 5% 6% 31%	2238
	11th to 20th	Day	16% 9% 3 7% 5% 5% 5% 4 5% 6% 36%	2473
	21st to end	Day	19% 8% 3 7% 5% 4 5% 4 6% 7% 33%	2600
May	1st to 10th	Day	19% 9% 4 8% 5% 5% 6% 5% 6% 7% 26%	5862
	11th to 20th	Day	18% 9% 3 8% 5% 5% 5% 3 7% 8% 30%	5861
	21st to end	Day	17% 7% 3 7% 5% 5% 5% 4 7% 9% 33%	6433
June	1st to 10th	Day	13% 6% 2 6% 5% 5% 5% 5% 7% 9% 37%	2600
	11th to 20th	Day	12% 6% 3 7% 5% 6% 6% 5% 7% 9% 35%	2600
	21st to end	Day	12% 6% 2 6% 4 5% 5% 5% 7% 9% 37%	2600
July	1st to 10th	Day	9% 6% 2 7% 5% 5% 5% 5% 7% 9% 40%	4250
	11th to 20th	Day	10% 6% 2 6% 5% 4 5% 4 7% 9% 41%	4250
	21st to end	Day	14% 9% 3 7% 5% 5% 5% 4 6% 8% 33%	4466
August	1st to 10th	Day	10% 7% 3 7% 5% 6% 6% 5% 7% 11% 33%	4104
	11th to 20th	Day	9% 6% 3 7% 5% 5% 6% 5% 7% 9% 38%	4044
	21st to end	Day	6% 3 2 5% 5% 4 6% 5% 7% 10% 47%	4384
September	1st to 10th	Day	15% 5% 2 4 4 3 4 3 5% 7% 47%	2180
	11th to 20th	Day	11% 6% 2 5% 4 4 4 4 6% 8% 48%	2090
	21st to end	Day	20% 8% 3 6% 4 4 4 3 5% 6% 38%	2090
October	1st to 10th	Day	14% 6% 3 6% 4 4 4 4 6% 8% 42%	1957
	11th to 20th	Day	16% 8% 2 7% 5% 4 4 3 5% 5% 40%	1900
	21st to end	Day	21% 10% 3 5% 4 3 3 2 4 6% 39%	2090
November	1st to 10th	Day	12% 8% 2 6% 4 4 3 3 4 5% 49%	1829
	11th to 20th	Day	18% 14% 3 6% 4 3 3 3 6% 7% 34%	1800
	21st to end	Day	18% 13% 3 9% 4 4 4 3 5% 7% 31%	1670
December	1st to 10th	Day	20% 12% 5% 15% 5% 3 4 3 4 4 25%	2600
	11th to 20th	Day	24% 16% 5% 10% 4 3 3 3 4 5% 23%	2990
	21st to end	Day	21% 18% 5% 10% 6% 5% 5% 3 5% 5% 17%	4466
January	1st to 10th	Night	15% 17% 8% 19% 6% 4 4 3 4 4 18%	5889
	11th to 20th	Night	17% 17% 6% 13% 8% 5% 4 2 4 5% 19%	5900
	21st to end	Night	22% 13% 5% 11% 6% 4 3 2 4 4 26%	6490
February	1st to 10th	Night	21% 13% 4 9% 5% 4 4 4 4 5% 27%	2600
	11th to 20th	Night	21% 13% 4 10% 5% 5% 4 3 4 4 26%	2458
	21st to end	Night	21% 14% 5% 9% 5% 4 4 3 4 4 28%	1980
March	1st to 10th	Night	20% 13% 4 7% 4 3 3 3 4 6% 34%	4948
	11th to 20th	Night	11% 9% 4 7% 4 4 4 3 6% 7% 40%	4980
	21st to end	Night	17% 9% 3 8% 5% 4 4 3 4 6% 35%	5467
April	1st to 10th	Night	18% 10% 3 6% 5% 4 4 3 5% 6% 35%	2160
	11th to 20th	Night	16% 8% 3 6% 5% 3 4 4 6% 8% 37%	1892
	21st to end	Night	16% 8% 3 7% 4 4 5% 3 5% 8% 37%	1800
May	1st to 10th	Night	25% 11% 3 8% 5% 4 4 4 5% 6% 25%	4033
	11th to 20th	Night	16% 8% 3 6% 4 5% 5% 4 6% 9% 36%	4032
	21st to end	Night	16% 8% 3 8% 5% 3 4 3 6% 9% 34%	4421
June	1st to 10th	Night	11% 7% 3 6% 5% 4 4 3 5% 8% 44%	1800
	11th to 20th	Night	11% 6% 2 6% 5% 4 5% 4 7% 10% 40%	1695
	21st to end	Night	11% 6% 2 5% 4 4 4 4 7% 10% 44%	1800
July	1st to 10th	Night	9% 7% 3 7% 4 4 5% 4 6% 8% 42%	2930
	11th to 20th	Night	10% 6% 2 6% 4 5% 4 3 7% 9% 44%	2930
	21st to end	Night	10% 7% 3 7% 6% 5% 5% 4 7% 8% 39%	3087
August	1st to 10th	Night	9% 8% 3 8% 5% 5% 5% 4 7% 10% 35%	2825
	11th to 20th	Night	11% 7% 4 7% 5% 4 4 4 5% 7% 42%	2785
	21st to end	Night	6% 4 2 6% 4 5% 6% 5% 6% 10% 47%	3238
September	1st to 10th	Night	12% 5% 2 5% 3 4 4 3 6% 6% 51%	1995
	11th to 20th	Night	9% 5% 2 5% 3 3 3 4 5% 7% 54%	2090
	21st to end	Night	15% 7% 3 7% 5% 4 4 4 4 7% 42%	2090
October	1st to 10th	Night	12% 5% 2 6% 4 4 4 3 5% 7% 46%	2223
	11th to 20th	Night	15% 8% 2 6% 4 4 4 3 5% 6% 43%	2280
	21st to end	Night	22% 7% 2 6% 4 3 4 3 4 6% 40%	2508
November	1st to 10th	Night	13% 8% 3 5% 4 3 3 3 5% 6% 48%	2465
	11th to 20th	Night	17% 11% 3 7% 5% 5% 5% 4 5% 6% 34%	2600
	21st to end	Night	19% 11% 3 8% 5% 4 5% 3 5% 5% 31%	2725
December	1st to 10th	Night	20% 13% 6% 14% 5% 4 4 3 4 5% 23%	4580
	11th to 20th	Night	19% 16% 7% 10% 4 4 4 3 4 4 24%	5186
	21st to end	Night	20% 18% 5% 9% 6% 5% 5% 3 4 5% 20%	6490

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	72% 4 10% 10% 4	4057
	11th to 20th	Day	73% 3 7% 9% 6% 1	4060
	21st to end	Day	69% 4 8% 12% 7%	4466
February	1st to 10th	Day	61% 4 11% 16% 8% 1	1800
	11th to 20th	Day	60% 5% 9% 16% 10%	1832
	21st to end	Day	58% 3 11% 17% 9% 2	1650
March	1st to 10th	Day	54% 4 8% 22% 9% 3	4903
	11th to 20th	Day	40% 6% 10% 30% 12% 2	4980
	21st to end	Day	51% 6% 9% 20% 13% 2	5465
April	1st to 10th	Day	53% 6% 10% 17% 12% 3	2238
	11th to 20th	Day	47% 6% 11% 16% 17% 3	2473
	21st to end	Day	48% 7% 10% 21% 13% 2	2600
May	1st to 10th	Day	53% 8% 10% 17% 9% 3	5897
	11th to 20th	Day	50% 7% 10% 21% 10% 1	5865
	21st to end	Day	44% 8% 14% 19% 12% 3	6447
June	1st to 10th	Day	40% 9% 13% 22% 15% 2	2600
	11th to 20th	Day	43% 9% 14% 21% 12% 1	2600
	21st to end	Day	40% 10% 14% 22% 14% 1	2600
July	1st to 10th	Day	38% 8% 12% 23% 16% 3	4185
	11th to 20th	Day	36% 8% 12% 29% 15% 1	4181
	21st to end	Day	47% 7% 10% 18% 16% 3	4324
August	1st to 10th	Day	41% 9% 13% 25% 11%	4091
	11th to 20th	Day	37% 9% 11% 29% 13%	4083
	21st to end	Day	30% 8% 15% 27% 18% 2	4384
September	1st to 10th	Day	36% 6% 10% 22% 22% 4	2180
	11th to 20th	Day	34% 6% 12% 29% 17% 3	2090
	21st to end	Day	46% 5% 11% 20% 17% 1	2090
October	1st to 10th	Day	28% 6% 9% 28% 27% 2	3256
	11th to 20th	Day	36% 6% 13% 24% 16% 5%	3140
	21st to end	Day	33% 4 12% 28% 21% 2	3428
November	1st to 10th	Day	39% 4 10% 28% 17% 3	1829
	11th to 20th	Day	50% 5% 9% 20% 14% 2	1800
	21st to end	Day	54% 5% 11% 18% 11% 1	1670
December	1st to 10th	Day	62% 4 13% 16% 4	2600
	11th to 20th	Day	65% 4 10% 17% 4	2986
	21st to end	Day	67% 6% 9% 12% 5%	4466
January	1st to 10th	Night	70% 4 8% 13% 4	5889
	11th to 20th	Night	69% 5% 9% 11% 6% 2	5900
	21st to end	Night	62% 4 10% 16% 7% 2	6490
February	1st to 10th	Night	59% 5% 11% 17% 8% 1	2600
	11th to 20th	Night	62% 4 9% 16% 9%	2460
	21st to end	Night	60% 4 8% 17% 8% 2	1980
March	1st to 10th	Night	52% 5% 6% 24% 12% 2	4948
	11th to 20th	Night	41% 5% 11% 30% 11% 3	4980
	21st to end	Night	49% 5% 8% 23% 13% 3	5467
April	1st to 10th	Night	50% 5% 10% 19% 14% 2	2160
	11th to 20th	Night	43% 7% 12% 19% 15% 4	1892
	21st to end	Night	44% 6% 12% 21% 16% 2	1800
May	1st to 10th	Night	57% 8% 11% 12% 7% 4	4060
	11th to 20th	Night	44% 8% 11% 25% 11% 1	4033
	21st to end	Night	45% 9% 12% 22% 9% 3	4429
June	1st to 10th	Night	38% 8% 10% 24% 18% 2	1800
	11th to 20th	Night	38% 8% 14% 22% 16% 3	1695
	21st to end	Night	34% 9% 15% 22% 18% 2	1800
July	1st to 10th	Night	38% 7% 10% 23% 17% 4	2885
	11th to 20th	Night	34% 8% 14% 28% 14% 2	2876
	21st to end	Night	39% 10% 12% 17% 17% 4	2988
August	1st to 10th	Night	42% 9% 15% 24% 10% 1	2814
	11th to 20th	Night	39% 6% 10% 24% 19% 1	2812
	21st to end	Night	30% 8% 12% 30% 17% 3	3238
September	1st to 10th	Night	34% 6% 13% 18% 22% 7%	1995
	11th to 20th	Night	30% 5% 14% 25% 24% 2	2090
	21st to end	Night	42% 6% 10% 21% 19% 2	2090
October	1st to 10th	Night	30% 5% 8% 29% 24% 4	3704
	11th to 20th	Night	33% 5% 12% 23% 20% 8%	3779
	21st to end	Night	33% 3 7% 27% 26% 3	4120
November	1st to 10th	Night	38% 4 11% 24% 19% 4	2465
	11th to 20th	Night	50% 5% 8% 20% 14% 3	2600
	21st to end	Night	54% 5% 10% 20% 9% 1	2725
December	1st to 10th	Night	63% 5% 11% 17% 4	4580
	11th to 20th	Night	63% 4 13% 16% 4	5189
	21st to end	Night	64% 6% 10% 14% 6%	6490

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	34% 24% 29% 9% 3 1	300
	11th to 20th	Day	37% 25% 29% 8% 1	300
	21st to end	Day	35% 28% 26% 8% 2 1	330
February	1st to 10th	Day	38% 20% 30% 10% 2	300
	11th to 20th	Day	43% 24% 28% 5% 1 1	300
	21st to end	Day	36% 21% 36% 7%	249
March	1st to 10th	Day	32% 20% 28% 16% 4	481
	11th to 20th	Day	33% 16% 33% 12% 6% 1	500
	21st to end	Day	32% 18% 33% 13% 4	550
April	1st to 10th	Day	29% 19% 30% 15% 6% 1	500
	11th to 20th	Day	27% 18% 26% 17% 8% 3	492
	21st to end	Day	28% 17% 27% 18% 8% 2	500
May	1st to 10th	Day	27% 20% 25% 16% 9% 3	503
	11th to 20th	Day	22% 13% 29% 20% 12% 4	527
	21st to end	Day	16% 11% 26% 26% 16% 5%	573
June	1st to 10th	Day	15% 9% 30% 28% 14% 5%	530
	11th to 20th	Day	16% 10% 25% 29% 15% 5%	530
	21st to end	Day	12% 8% 30% 28% 17% 5%	530
July	1st to 10th	Day	13% 6% 21% 27% 20% 13%	525
	11th to 20th	Day	12% 5% 24% 29% 20% 10%	524
	21st to end	Day	17% 5% 22% 28% 20% 8%	532
August	1st to 10th	Day	12% 5% 23% 28% 22% 9%	486
	11th to 20th	Day	15% 5% 21% 30% 18% 11%	479
	21st to end	Day	11% 4 20% 29% 22% 12%	539
September	1st to 10th	Day	16% 6% 19% 28% 22% 9%	490
	11th to 20th	Day	11% 4 16% 27% 31% 11%	490
	21st to end	Day	25% 9% 22% 24% 17% 3	490
October	1st to 10th	Day	14% 8% 26% 28% 19% 4	490
	11th to 20th	Day	23% 12% 27% 25% 12% 2	490
	21st to end	Day	27% 14% 30% 19% 10% 1	539
November	1st to 10th	Day	22% 14% 31% 21% 9% 3	367
	11th to 20th	Day	29% 16% 30% 18% 6% 1	300
	21st to end	Day	27% 22% 34% 15% 1 1	235
December	1st to 10th	Day	32% 21% 31% 12% 5% 1	200
	11th to 20th	Day	32% 24% 28% 13% 4 1	200
	21st to end	Day	34% 22% 25% 14% 5%	330
January	1st to 10th	Night	29% 20% 31% 17% 4	800
	11th to 20th	Night	32% 19% 28% 19% 2	800
	21st to end	Night	29% 18% 33% 19% 2	880
February	1st to 10th	Night	29% 14% 30% 24% 2	800
	11th to 20th	Night	32% 18% 33% 16% 1	783
	21st to end	Night	29% 18% 32% 19% 2	660
March	1st to 10th	Night	26% 16% 30% 25% 4	800
	11th to 20th	Night	27% 16% 28% 22% 6% 1	800
	21st to end	Night	26% 16% 32% 21% 5% 1	880
April	1st to 10th	Night	25% 16% 31% 22% 6%	800
	11th to 20th	Night	21% 15% 31% 24% 9% 1	708
	21st to end	Night	19% 10% 35% 29% 7% 1	600
May	1st to 10th	Night	20% 11% 28% 28% 12% 1	600
	11th to 20th	Night	18% 7% 27% 32% 16% 1	591
	21st to end	Night	13% 4 23% 34% 22% 4	650
June	1st to 10th	Night	14% 5% 21% 39% 20% 1	600
	11th to 20th	Night	13% 5% 20% 37% 22% 2	495
	21st to end	Night	13% 3 20% 37% 26% 2	600
July	1st to 10th	Night	11% 3 17% 35% 27% 6%	585
	11th to 20th	Night	9% 3 17% 35% 30% 5%	582
	21st to end	Night	12% 4 14% 34% 33% 3	624
August	1st to 10th	Night	9% 2 14% 40% 32% 3	567
	11th to 20th	Night	12% 3 16% 35% 29% 5%	564
	21st to end	Night	11% 2 16% 34% 31% 7%	689
September	1st to 10th	Night	14% 3 17% 33% 27% 6%	760
	11th to 20th	Night	11% 3 17% 32% 33% 4	760
	21st to end	Night	18% 6% 21% 32% 20% 4	760
October	1st to 10th	Night	15% 5% 22% 30% 25% 2	760
	11th to 20th	Night	20% 9% 26% 30% 13% 1	760
	21st to end	Night	25% 12% 22% 30% 11% 1	836
November	1st to 10th	Night	17% 10% 26% 31% 16%	780
	11th to 20th	Night	25% 14% 27% 25% 8% 1	800
	21st to end	Night	26% 13% 28% 25% 7% 1	800
December	1st to 10th	Night	32% 14% 28% 21% 5%	800
	11th to 20th	Night	28% 16% 28% 24% 5%	800
	21st to end	Night	30% 14% 28% 26% 2	880

Page generated at 2025-07-18 01:10:04. Version ac07

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