Camp Wood Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camp Wood Observatory clear sky chart from 2005-11-06 to 2024-12-24.

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	12% 6% 2 5% 4 3 4 3 5% 7% 50%	101349
	Night	11% 5% 2 4 3 3 3 3 5% 7% 55%	98896
Transparency	Day	33% 4 9% 22% 20% 11%	105273
	Night	29% 4 10% 21% 21% 14%	103099
Seeing	Day	14% 8% 25% 33% 18% 3	14885
	Night	13% 7% 28% 38% 13% 1	24927

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	10% 6% 2 3 2 2 2 2 3 5% 63%	2847
	11th to 20th	Day	10% 7% 2 3 2 2 3 3 5% 5% 59%	3039
	21st to end	Day	13% 7% 2 5% 3 3 3 3 4 8% 49%	3487
February	1st to 10th	Day	11% 8% 2 6% 4 3 3 3 4 5% 51%	1900
	11th to 20th	Day	14% 8% 2 5% 3 3 3 3 6% 5% 49%	1849
	21st to end	Day	13% 5% 2 4 2 2 3 3 4 7% 56%	1570
March	1st to 10th	Day	15% 9% 2 6% 3 3 3 3 3 5% 47%	3192
	11th to 20th	Day	22% 9% 2 7% 4 3 3 3 4 5% 37%	3480
	21st to end	Day	14% 6% 2 4 3 3 4 3 6% 7% 49%	3814
April	1st to 10th	Day	14% 7% 2 5% 3 3 4 3 6% 6% 48%	2123
	11th to 20th	Day	15% 5% 2 5% 5% 2 3 3 5% 6% 48%	2254
	21st to end	Day	15% 6% 2 5% 4 3 3 3 5% 5% 49%	2280
May	1st to 10th	Day	20% 6% 2 5% 4 3 3 3 5% 6% 41%	4045
	11th to 20th	Day	14% 6% 2 5% 4 3 4 3 5% 7% 47%	4082
	21st to end	Day	13% 6% 2 6% 4 4 5% 4 6% 9% 42%	4477
June	1st to 10th	Day	7% 4 2 4 3 4 4 4 6% 9% 52%	2470
	11th to 20th	Day	8% 5% 1 5% 4 4 4 4 6% 9% 50%	2470
	21st to end	Day	9% 5% 2 5% 6% 6% 6% 6% 6% 8% 40%	2470
July	1st to 10th	Day	8% 5% 2 5% 4 4 4 4 6% 7% 51%	4120
	11th to 20th	Day	5% 3 2 5% 4 4 5% 5% 7% 9% 51%	4120
	21st to end	Day	9% 5% 2 5% 4 4 5% 5% 7% 9% 46%	4320
August	1st to 10th	Day	2 2 1 3 3 3 3 3 5% 8% 69%	3785
	11th to 20th	Day	4 2 1 2 3 3 4 3 5% 9% 63%	3726
	21st to end	Day	6% 4 2 5% 4 5% 5% 4 5% 9% 51%	4180
September	1st to 10th	Day	11% 6% 2 6% 5% 5% 5% 4 7% 8% 40%	2109
	11th to 20th	Day	11% 6% 2 7% 4 5% 5% 3 6% 7% 42%	2090
	21st to end	Day	9% 5% 2 6% 4 4 5% 4 7% 6% 48%	2090
October	1st to 10th	Day	8% 4 1 5% 4 4 3 3 5% 7% 55%	2090
	11th to 20th	Day	15% 5% 2 4 3 3 3 3 4 6% 52%	2090
	21st to end	Day	14% 5% 2 4 3 2 3 2 4 4 58%	2109
November	1st to 10th	Day	15% 7% 2 4 4 3 4 3 4 6% 48%	1858
	11th to 20th	Day	13% 6% 2 4 3 3 3 2 4 6% 53%	1800
	21st to end	Day	14% 9% 2 4 4 3 3 3 4 5% 50%	1800
December	1st to 10th	Day	16% 6% 2 5% 3 3 3 3 5% 5% 50%	1800
	11th to 20th	Day	15% 8% 2 6% 4 3 3 3 4 4 47%	2251
	21st to end	Day	14% 5% 2 4 2 2 3 2 3 5% 57%	3162
January	1st to 10th	Night	11% 4 1 3 2 2 2 2 4 7% 60%	4108
	11th to 20th	Night	9% 5% 1 3 2 2 2 1 2 4 69%	3960
	21st to end	Night	17% 7% 2 5% 3 2 2 2 4 6% 49%	4180
February	1st to 10th	Night	11% 8% 1 4 2 3 3 3 5% 6% 55%	2280
	11th to 20th	Night	15% 6% 1 4 3 3 3 3 4 5% 54%	2218
	21st to end	Night	12% 5% 2 4 3 3 3 3 5% 6% 53%	1884
March	1st to 10th	Night	11% 7% 2 4 3 3 4 3 6% 7% 50%	3670
	11th to 20th	Night	18% 8% 3 7% 4 4 4 3 4 5% 41%	3480
	21st to end	Night	13% 7% 2 5% 3 3 3 3 4 6% 51%	3817
April	1st to 10th	Night	10% 5% 1 4 4 3 3 3 5% 8% 52%	2052
	11th to 20th	Night	15% 5% 2 4 4 4 3 3 5% 6% 50%	1877
	21st to end	Night	15% 6% 2 5% 3 3 3 3 3 5% 52%	1900
May	1st to 10th	Night	20% 8% 2 4 3 2 3 2 5% 6% 45%	2855
	11th to 20th	Night	11% 4 2 5% 3 3 3 2 5% 6% 56%	2823
	21st to end	Night	10% 5% 2 5% 3 3 3 3 5% 8% 52%	3090
June	1st to 10th	Night	3 3 1 3 3 3 3 3 6% 10% 62%	1710
	11th to 20th	Night	4 3 1 4 3 3 4 3 7% 9% 59%	1710
	21st to end	Night	7% 4 1 3 4 3 3 3 6% 11% 53%	1710
July	1st to 10th	Night	5% 3 2 4 3 3 4 4 6% 9% 59%	2850
	11th to 20th	Night	5% 3 1 4 3 3 4 4 6% 9% 59%	2850
	21st to end	Night	12% 4 1 5% 4 4 4 3 6% 9% 49%	3238
August	1st to 10th	Night	1 1 1 2 1 2 3 3 5% 8% 74%	3155
	11th to 20th	Night	3 2 1 3 2 2 3 3 5% 9% 66%	3113
	21st to end	Night	5% 3 2 5% 3 4 4 3 6% 10% 53%	3487
September	1st to 10th	Night	9% 6% 2 5% 3 4 4 4 6% 9% 48%	2071
	11th to 20th	Night	9% 6% 2 6% 4 3 4 4 5% 8% 50%	2090
	21st to end	Night	8% 4 2 4 3 3 3 4 6% 8% 54%	2090
October	1st to 10th	Night	7% 4 2 3 3 2 3 3 5% 7% 62%	2090
	11th to 20th	Night	13% 5% 1 3 2 3 3 3 4 6% 57%	2090
	21st to end	Night	12% 4 1 3 2 2 2 1 3 3 67%	2468
November	1st to 10th	Night	14% 6% 2 3 2 2 3 2 4 5% 56%	2436
	11th to 20th	Night	10% 5% 2 4 3 3 3 2 5% 6% 58%	2600
	21st to end	Night	15% 6% 2 3 3 3 4 3 4 6% 52%	2600
December	1st to 10th	Night	15% 7% 2 4 2 3 3 3 5% 6% 51%	2600
	11th to 20th	Night	15% 7% 2 5% 4 3 3 3 4 5% 50%	3166
	21st to end	Night	16% 5% 1 3 2 2 2 2 4 7% 55%	4578

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	27% 2 3 14% 28% 26%	2848
	11th to 20th	Day	27% 4 4 15% 29% 21%	3039
	21st to end	Day	36% 3 6% 16% 28% 11%	3487
February	1st to 10th	Day	37% 3 5% 14% 21% 20%	1900
	11th to 20th	Day	38% 3 5% 17% 21% 16%	1859
	21st to end	Day	31% 3 7% 17% 23% 19%	1570
March	1st to 10th	Day	42% 3 5% 14% 20% 16%	3192
	11th to 20th	Day	51% 4 5% 12% 16% 12%	3480
	21st to end	Day	34% 4 9% 16% 17% 21%	3814
April	1st to 10th	Day	37% 4 7% 16% 19% 17%	2123
	11th to 20th	Day	36% 4 6% 20% 17% 16%	2254
	21st to end	Day	38% 3 7% 19% 18% 14%	2280
May	1st to 10th	Day	43% 5% 9% 17% 16% 10%	4083
	11th to 20th	Day	37% 5% 8% 21% 20% 9%	4086
	21st to end	Day	38% 6% 10% 26% 16% 4	4489
June	1st to 10th	Day	27% 6% 13% 30% 20% 4	2470
	11th to 20th	Day	30% 6% 12% 26% 20% 6%	2470
	21st to end	Day	39% 7% 12% 22% 16% 5%	2470
July	1st to 10th	Day	31% 6% 16% 35% 12% 1	4056
	11th to 20th	Day	26% 7% 19% 31% 15% 2	4051
	21st to end	Day	29% 7% 19% 29% 15% 1	4184
August	1st to 10th	Day	15% 4 11% 41% 28% 1	3772
	11th to 20th	Day	18% 5% 21% 41% 13% 2	3762
	21st to end	Day	29% 7% 16% 26% 21% 2	4179
September	1st to 10th	Day	41% 7% 11% 18% 16% 7%	2109
	11th to 20th	Day	39% 6% 11% 22% 18% 4	2090
	21st to end	Day	34% 5% 10% 21% 18% 12%	2090
October	1st to 10th	Day	19% 4 6% 15% 22% 34%	3480
	11th to 20th	Day	32% 4 6% 15% 18% 25%	3458
	21st to end	Day	29% 3 4 17% 34% 12%	3459
November	1st to 10th	Day	38% 4 9% 19% 20% 12%	1858
	11th to 20th	Day	35% 3 6% 18% 20% 18%	1800
	21st to end	Day	39% 2 5% 20% 19% 15%	1800
December	1st to 10th	Day	38% 2 8% 18% 23% 11%	1800
	11th to 20th	Day	41% 3 5% 11% 21% 18%	2249
	21st to end	Day	33% 3 4 15% 30% 16%	3162
January	1st to 10th	Night	27% 3 3 13% 28% 26%	4108
	11th to 20th	Night	22% 2 3 18% 26% 28%	3960
	21st to end	Night	39% 3 4 13% 26% 15%	4180
February	1st to 10th	Night	31% 4 8% 15% 20% 23%	2280
	11th to 20th	Night	34% 3 6% 18% 22% 18%	2218
	21st to end	Night	31% 5% 6% 16% 21% 20%	1884
March	1st to 10th	Night	34% 5% 9% 16% 21% 15%	3670
	11th to 20th	Night	46% 4 7% 13% 15% 15%	3480
	21st to end	Night	35% 3 11% 16% 16% 19%	3817
April	1st to 10th	Night	30% 5% 10% 19% 17% 19%	2052
	11th to 20th	Night	36% 4 9% 16% 16% 19%	1877
	21st to end	Night	37% 4 9% 19% 16% 15%	1900
May	1st to 10th	Night	40% 5% 9% 18% 15% 13%	2882
	11th to 20th	Night	30% 4 11% 23% 22% 10%	2824
	21st to end	Night	31% 5% 13% 29% 14% 8%	3099
June	1st to 10th	Night	17% 4 18% 36% 21% 3	1710
	11th to 20th	Night	22% 5% 14% 29% 24% 6%	1710
	21st to end	Night	26% 7% 18% 26% 18% 5%	1710
July	1st to 10th	Night	22% 6% 23% 38% 11% 1	2805
	11th to 20th	Night	23% 7% 20% 30% 18% 2	2796
	21st to end	Night	29% 7% 19% 32% 12% 1	3135
August	1st to 10th	Night	10% 4 16% 42% 27% 1	3144
	11th to 20th	Night	17% 5% 26% 40% 10% 2	3143
	21st to end	Night	25% 8% 20% 28% 17% 2	3487
September	1st to 10th	Night	33% 6% 14% 22% 17% 8%	2071
	11th to 20th	Night	32% 7% 17% 22% 17% 5%	2090
	21st to end	Night	28% 7% 11% 23% 19% 12%	2090
October	1st to 10th	Night	16% 3 8% 15% 21% 36%	3480
	11th to 20th	Night	27% 3 6% 13% 25% 25%	3460
	21st to end	Night	23% 2 4 16% 38% 16%	4056
November	1st to 10th	Night	32% 3 7% 20% 24% 14%	2436
	11th to 20th	Night	28% 4 7% 21% 21% 19%	2600
	21st to end	Night	35% 3 8% 17% 20% 17%	2600
December	1st to 10th	Night	35% 3 9% 18% 21% 14%	2600
	11th to 20th	Night	38% 3 5% 15% 18% 21%	3167
	21st to end	Night	32% 3 5% 15% 28% 18%	4578

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	20% 13% 37% 25% 6%	270
	11th to 20th	Day	22% 11% 33% 27% 7% 1	270
	21st to end	Day	15% 15% 37% 25% 8%	297
February	1st to 10th	Day	24% 16% 27% 23% 8%	270
	11th to 20th	Day	25% 16% 33% 19% 7%	270
	21st to end	Day	20% 18% 44% 16% 3	225
March	1st to 10th	Day	19% 19% 44% 16% 3	270
	11th to 20th	Day	20% 20% 40% 19% 2	270
	21st to end	Day	22% 18% 42% 17% 1	297
April	1st to 10th	Day	16% 18% 43% 21% 2	303
	11th to 20th	Day	15% 20% 40% 22% 3	452
	21st to end	Day	15% 16% 45% 20% 3	460
May	1st to 10th	Day	16% 11% 41% 27% 4	629
	11th to 20th	Day	19% 9% 36% 28% 6% 1	675
	21st to end	Day	17% 8% 34% 33% 7%	734
June	1st to 10th	Day	7% 3 23% 51% 15% 1	680
	11th to 20th	Day	10% 2 24% 48% 15% 1	680
	21st to end	Day	9% 3 19% 39% 26% 4	680
July	1st to 10th	Day	11% 3 12% 39% 30% 5%	671
	11th to 20th	Day	6% 1 7% 43% 39% 4	668
	21st to end	Day	4 2 7% 44% 38% 5%	656
August	1st to 10th	Day	2 5% 47% 38% 8%	487
	11th to 20th	Day	7% 1 7% 38% 39% 7%	477
	21st to end	Day	6% 2 8% 37% 38% 10%	539
September	1st to 10th	Day	10% 2 8% 33% 38% 9%	319
	11th to 20th	Day	8% 1 8% 30% 43% 10%	300
	21st to end	Day	9% 2 8% 40% 33% 7%	300
October	1st to 10th	Day	6% 5% 14% 40% 28% 6%	300
	11th to 20th	Day	15% 5% 18% 45% 15% 2	300
	21st to end	Day	20% 11% 26% 28% 12% 3	330
November	1st to 10th	Day	21% 7% 28% 31% 13% 1	300
	11th to 20th	Day	23% 9% 26% 24% 15% 4	300
	21st to end	Day	22% 13% 32% 22% 8% 2	300
December	1st to 10th	Day	21% 8% 28% 30% 11% 2	300
	11th to 20th	Day	21% 17% 27% 25% 9% 1	300
	21st to end	Day	19% 10% 32% 27% 10% 1	306
January	1st to 10th	Night	15% 8% 31% 36% 9% 1	950
	11th to 20th	Night	18% 9% 28% 37% 8%	855
	21st to end	Night	20% 9% 30% 34% 7%	836
February	1st to 10th	Night	19% 10% 32% 32% 7%	760
	11th to 20th	Night	19% 13% 36% 26% 6%	744
	21st to end	Night	18% 11% 44% 26% 1	628
March	1st to 10th	Night	19% 12% 38% 26% 4 1	722
	11th to 20th	Night	16% 13% 36% 31% 4	570
	21st to end	Night	15% 13% 46% 21% 4	627
April	1st to 10th	Night	10% 12% 48% 28% 2	570
	11th to 20th	Night	16% 14% 49% 19% 2	563
	21st to end	Night	16% 12% 46% 22% 3 1	570
May	1st to 10th	Night	14% 13% 43% 28% 2	570
	11th to 20th	Night	14% 8% 43% 29% 6%	561
	21st to end	Night	12% 9% 41% 32% 7%	617
June	1st to 10th	Night	4 2 35% 49% 8%	570
	11th to 20th	Night	6% 1 42% 43% 7%	570
	21st to end	Night	5% 3 27% 49% 15%	570
July	1st to 10th	Night	7% 3 17% 55% 18% 1	555
	11th to 20th	Night	4 1 16% 56% 22%	552
	21st to end	Night	6% 1 10% 60% 22% 1	624
August	1st to 10th	Night	1 1 7% 62% 28% 1	567
	11th to 20th	Night	4 2 10% 55% 28% 1	564
	21st to end	Night	5% 1 11% 49% 31% 2	627
September	1st to 10th	Night	8% 1 11% 45% 32% 2	570
	11th to 20th	Night	12% 1 9% 47% 30% 1	570
	21st to end	Night	9% 2 14% 43% 29% 3	570
October	1st to 10th	Night	9% 1 16% 49% 23% 2	570
	11th to 20th	Night	12% 4 23% 41% 18% 1	570
	21st to end	Night	12% 8% 25% 35% 19% 2	796
November	1st to 10th	Night	15% 7% 20% 38% 18% 1	876
	11th to 20th	Night	13% 7% 26% 38% 15% 2	1000
	21st to end	Night	18% 9% 25% 36% 10% 1	1000
December	1st to 10th	Night	17% 7% 25% 40% 11% 1	1000
	11th to 20th	Night	21% 11% 25% 33% 10%	1000
	21st to end	Night	17% 9% 27% 39% 8% 1	1063

Page generated at 2024-12-21 03:13:48. Version ac07

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