Camp Susque Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camp Susque Observatory clear sky chart from 2005-11-05 to 2024-10-14.

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	18% 9% 3 7% 5% 5% 5% 4 5% 7% 33%	101220
	Night	18% 9% 3 7% 5% 4 4 3 5% 6% 34%	97337
Transparency	Day	50% 5% 12% 22% 10% 1	100984
	Night	50% 4 12% 22% 11% 1	97197
Seeing	Day	25% 15% 27% 20% 10% 4	14678
	Night	23% 13% 25% 28% 11% 1	24001

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	15% 17% 5% 8% 6% 4 4 3 4 5% 28%	2517
	11th to 20th	Day	14% 15% 9% 15% 7% 5% 4 3 3 5% 20%	2684
	21st to end	Day	21% 17% 8% 10% 5% 4 4 3 4 5% 19%	3124
February	1st to 10th	Day	16% 16% 4 9% 7% 5% 5% 4 5% 4 25%	1710
	11th to 20th	Day	14% 11% 4 9% 7% 5% 4 3 5% 6% 29%	1678
	21st to end	Day	19% 13% 4 9% 6% 4 4 2 5% 5% 30%	1570
March	1st to 10th	Day	24% 11% 3 7% 5% 4 4 3 4 5% 31%	3303
	11th to 20th	Day	11% 12% 4 8% 5% 4 5% 3 4 6% 37%	3480
	21st to end	Day	16% 11% 3 6% 5% 3 4 3 5% 5% 37%	3909
April	1st to 10th	Day	18% 11% 3 7% 6% 5% 4 3 5% 6% 32%	2280
	11th to 20th	Day	18% 10% 3 7% 4 4 3 4 5% 6% 34%	2254
	21st to end	Day	19% 8% 2 7% 4 5% 4 4 5% 6% 35%	2312
May	1st to 10th	Day	28% 7% 2 6% 4 4 4 3 5% 7% 31%	4194
	11th to 20th	Day	25% 9% 3 8% 5% 4 4 4 5% 7% 26%	4398
	21st to end	Day	16% 5% 2 5% 4 5% 4 4 6% 8% 41%	4837
June	1st to 10th	Day	15% 6% 3 6% 6% 6% 5% 4 6% 8% 34%	2660
	11th to 20th	Day	16% 6% 2 7% 6% 5% 5% 4 6% 8% 35%	2660
	21st to end	Day	14% 5% 3 6% 5% 5% 6% 5% 7% 9% 36%	2660
July	1st to 10th	Day	9% 7% 2 7% 6% 6% 6% 5% 7% 10% 36%	4440
	11th to 20th	Day	8% 6% 3 6% 6% 5% 5% 5% 8% 12% 36%	4440
	21st to end	Day	12% 6% 2 8% 7% 6% 6% 5% 7% 7% 34%	4604
August	1st to 10th	Day	21% 7% 3 7% 5% 6% 5% 4 5% 7% 29%	4104
	11th to 20th	Day	17% 6% 3 7% 6% 5% 6% 5% 7% 8% 31%	3953
	21st to end	Day	17% 4 2 4 4 4 5% 5% 6% 9% 40%	4180
September	1st to 10th	Day	18% 5% 2 5% 4 4 5% 4 5% 6% 40%	2280
	11th to 20th	Day	16% 5% 2 5% 4 3 4 4 4 5% 48%	2280
	21st to end	Day	25% 6% 2 6% 3 4 3 3 5% 6% 35%	2003
October	1st to 10th	Day	20% 8% 2 5% 5% 3 4 3 5% 7% 39%	1900
	11th to 20th	Day	23% 7% 3 6% 5% 4 4 4 6% 7% 33%	1830
	21st to end	Day	22% 9% 3 7% 5% 4 5% 5% 5% 5% 30%	1980
November	1st to 10th	Day	15% 7% 2 7% 4 4 4 3 4 7% 42%	1676
	11th to 20th	Day	18% 11% 2 7% 5% 4 4 4 6% 5% 34%	1602
	21st to end	Day	18% 12% 3 7% 5% 4 3 4 6% 5% 32%	1520
December	1st to 10th	Day	21% 15% 5% 9% 6% 4 4 2 4 5% 23%	1520
	11th to 20th	Day	22% 11% 5% 7% 5% 4 4 3 5% 6% 27%	1906
	21st to end	Day	24% 17% 4 10% 6% 5% 4 3 3 5% 19%	2772
January	1st to 10th	Night	17% 13% 4 7% 6% 5% 5% 4 5% 6% 29%	4429
	11th to 20th	Night	16% 15% 6% 13% 5% 5% 4 3 5% 5% 24%	4273
	21st to end	Night	24% 13% 4 11% 6% 5% 5% 3 4 4 21%	4532
February	1st to 10th	Night	16% 12% 4 8% 5% 5% 5% 4 6% 6% 29%	2470
	11th to 20th	Night	15% 11% 3 9% 6% 5% 6% 3 5% 7% 30%	2387
	21st to end	Night	18% 11% 3 9% 6% 5% 5% 3 5% 5% 29%	1884
March	1st to 10th	Night	24% 14% 3 6% 4 4 4 3 5% 5% 29%	3533
	11th to 20th	Night	14% 13% 4 7% 4 4 4 4 6% 7% 34%	3479
	21st to end	Night	16% 10% 2 7% 4 4 4 3 4 5% 40%	3722
April	1st to 10th	Night	20% 13% 4 7% 4 4 4 3 5% 6% 31%	1900
	11th to 20th	Night	18% 9% 2 6% 4 4 4 5% 5% 7% 36%	1875
	21st to end	Night	18% 8% 2 6% 4 4 5% 3 5% 7% 40%	1883
May	1st to 10th	Night	31% 7% 2 6% 3 4 3 3 4 5% 31%	2747
	11th to 20th	Night	27% 9% 2 6% 4 4 4 4 5% 6% 30%	2495
	21st to end	Night	16% 5% 2 6% 4 4 5% 3 6% 8% 40%	2738
June	1st to 10th	Night	15% 6% 2 6% 4 3 5% 4 4 9% 42%	1520
	11th to 20th	Night	13% 6% 3 5% 4 5% 5% 4 7% 9% 39%	1520
	21st to end	Night	13% 5% 2 6% 5% 4 4 4 7% 9% 41%	1520
July	1st to 10th	Night	10% 7% 3 7% 5% 4 4 4 7% 8% 41%	2520
	11th to 20th	Night	9% 5% 2 6% 5% 4 5% 5% 7% 10% 41%	2520
	21st to end	Night	15% 6% 2 6% 4 4 4 3 5% 6% 43%	2946
August	1st to 10th	Night	20% 6% 1 6% 5% 5% 5% 4 6% 8% 36%	2825
	11th to 20th	Night	18% 7% 2 6% 4 3 4 3 5% 6% 42%	2844
	21st to end	Night	16% 4 2 5% 4 4 5% 4 6% 8% 44%	3476
September	1st to 10th	Night	16% 6% 2 5% 4 4 4 3 5% 6% 44%	1900
	11th to 20th	Night	15% 5% 1 5% 3 3 3 3 4 7% 50%	1900
	21st to end	Night	21% 6% 2 5% 4 4 3 3 5% 6% 40%	2173
October	1st to 10th	Night	20% 7% 2 6% 3 4 4 3 4 6% 41%	2280
	11th to 20th	Night	20% 8% 2 5% 4 4 4 4 4 7% 39%	2203
	21st to end	Night	23% 10% 2 6% 3 3 4 3 5% 7% 33%	2376
November	1st to 10th	Night	13% 8% 3 6% 4 3 3 3 5% 7% 45%	2401
	11th to 20th	Night	20% 9% 3 7% 4 4 4 5% 6% 6% 32%	2574
	21st to end	Night	16% 10% 3 8% 6% 4 5% 4 5% 6% 32%	2660
December	1st to 10th	Night	20% 13% 4 7% 5% 5% 5% 4 5% 7% 24%	2660
	11th to 20th	Night	20% 11% 3 9% 6% 5% 5% 4 5% 5% 28%	3288
	21st to end	Night	23% 13% 5% 9% 6% 4 5% 4 5% 7% 20%	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	58% 3 12% 19% 5% 2	2518
	11th to 20th	Day	69% 3 8% 13% 6% 1	2684
	21st to end	Day	69% 3 8% 15% 4 1	3124
February	1st to 10th	Day	62% 4 10% 16% 7% 1	1710
	11th to 20th	Day	56% 4 8% 22% 9% 1	1687
	21st to end	Day	58% 2 9% 21% 8% 2	1570
March	1st to 10th	Day	57% 3 9% 23% 7% 1	3306
	11th to 20th	Day	49% 4 14% 22% 9% 3	3480
	21st to end	Day	50% 3 9% 23% 15% 2	3909
April	1st to 10th	Day	53% 4 9% 20% 11% 3	2280
	11th to 20th	Day	50% 4 11% 19% 14% 2	2254
	21st to end	Day	49% 4 8% 20% 15% 4	2312
May	1st to 10th	Day	54% 4 8% 22% 10% 1	4206
	11th to 20th	Day	58% 5% 10% 19% 7% 1	4402
	21st to end	Day	40% 6% 11% 27% 14% 2	4837
June	1st to 10th	Day	47% 6% 12% 20% 13% 1	2660
	11th to 20th	Day	45% 6% 15% 21% 13% 2	2660
	21st to end	Day	42% 6% 14% 26% 12%	2660
July	1st to 10th	Day	40% 8% 16% 24% 11% 1	4370
	11th to 20th	Day	36% 9% 18% 24% 12% 1	4365
	21st to end	Day	44% 8% 12% 22% 13% 1	4457
August	1st to 10th	Day	52% 6% 12% 19% 11%	4091
	11th to 20th	Day	45% 8% 14% 25% 7%	3992
	21st to end	Day	39% 6% 13% 31% 10% 2	4180
September	1st to 10th	Day	42% 6% 11% 25% 14% 2	2280
	11th to 20th	Day	38% 4 11% 25% 20% 2	2280
	21st to end	Day	48% 4 12% 19% 15% 2	2003
October	1st to 10th	Day	46% 5% 11% 23% 14% 1	1900
	11th to 20th	Day	50% 4 11% 25% 10%	1831
	21st to end	Day	54% 5% 12% 20% 8% 1	1980
November	1st to 10th	Day	43% 4 13% 22% 15% 3	1676
	11th to 20th	Day	51% 4 12% 21% 9% 2	1602
	21st to end	Day	52% 4 13% 22% 7% 1	1520
December	1st to 10th	Day	65% 3 11% 14% 6% 1	1520
	11th to 20th	Day	58% 3 16% 17% 5%	1906
	21st to end	Day	69% 4 10% 13% 4	2772
January	1st to 10th	Night	56% 3 13% 20% 7% 1	4429
	11th to 20th	Night	62% 3 12% 16% 7% 1	4273
	21st to end	Night	68% 3 8% 16% 5% 1	4532
February	1st to 10th	Night	55% 4 13% 20% 9%	2470
	11th to 20th	Night	54% 4 10% 20% 10% 1	2389
	21st to end	Night	57% 3 9% 19% 11% 2	1884
March	1st to 10th	Night	58% 3 8% 21% 8% 1	3543
	11th to 20th	Night	50% 4 13% 24% 8% 1	3480
	21st to end	Night	47% 3 8% 22% 17% 3	3722
April	1st to 10th	Night	55% 4 8% 19% 12% 2	1900
	11th to 20th	Night	46% 5% 11% 21% 15% 2	1875
	21st to end	Night	45% 3 10% 23% 16% 2	1883
May	1st to 10th	Night	56% 4 8% 23% 8% 2	2754
	11th to 20th	Night	56% 5% 13% 16% 9% 1	2496
	21st to end	Night	41% 6% 14% 20% 14% 4	2739
June	1st to 10th	Night	41% 5% 11% 26% 15% 2	1520
	11th to 20th	Night	40% 5% 14% 26% 12% 2	1520
	21st to end	Night	39% 7% 12% 28% 14% 1	1520
July	1st to 10th	Night	39% 7% 13% 23% 17% 2	2480
	11th to 20th	Night	35% 8% 16% 25% 16% 1	2472
	21st to end	Night	40% 6% 12% 20% 20% 1	2852
August	1st to 10th	Night	46% 8% 14% 23% 9% 1	2814
	11th to 20th	Night	42% 5% 13% 27% 12%	2871
	21st to end	Night	37% 6% 13% 32% 11% 1	3476
September	1st to 10th	Night	40% 5% 10% 27% 16% 3	1900
	11th to 20th	Night	34% 5% 12% 28% 20% 2	1900
	21st to end	Night	44% 4 11% 24% 16% 1	2173
October	1st to 10th	Night	44% 5% 12% 24% 15% 1	2280
	11th to 20th	Night	45% 6% 12% 24% 12% 2	2207
	21st to end	Night	51% 3 13% 22% 11% 1	2376
November	1st to 10th	Night	39% 4 14% 24% 16% 2	2401
	11th to 20th	Night	51% 4 11% 21% 11% 3	2574
	21st to end	Night	51% 4 13% 24% 7% 1	2660
December	1st to 10th	Night	59% 4 13% 18% 6%	2660
	11th to 20th	Night	58% 4 11% 18% 8%	3288
	21st to end	Night	65% 4 13% 16% 3	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	32% 22% 31% 12% 2 1	180
	11th to 20th	Day	37% 22% 32% 8% 1	227
	21st to end	Day	30% 26% 30% 10% 2 1	297
February	1st to 10th	Day	31% 27% 30% 10% 2	270
	11th to 20th	Day	37% 23% 34% 5% 1	285
	21st to end	Day	36% 21% 26% 15% 2	382
March	1st to 10th	Day	32% 20% 27% 16% 3	460
	11th to 20th	Day	30% 24% 27% 14% 3 1	460
	21st to end	Day	32% 23% 25% 14% 5% 2	506
April	1st to 10th	Day	31% 22% 27% 14% 5% 1	460
	11th to 20th	Day	25% 27% 20% 16% 8% 3	452
	21st to end	Day	28% 20% 30% 14% 6% 2	460
May	1st to 10th	Day	34% 15% 23% 16% 8% 3	463
	11th to 20th	Day	25% 16% 25% 20% 9% 4	487
	21st to end	Day	21% 10% 26% 22% 15% 5%	529
June	1st to 10th	Day	18% 15% 29% 22% 13% 2	490
	11th to 20th	Day	17% 13% 29% 25% 14% 2	490
	21st to end	Day	18% 11% 33% 23% 11% 4	490
July	1st to 10th	Day	14% 6% 27% 29% 19% 6%	485
	11th to 20th	Day	11% 9% 29% 29% 18% 5%	484
	21st to end	Day	14% 8% 30% 29% 14% 5%	532
August	1st to 10th	Day	14% 8% 23% 27% 21% 6%	486
	11th to 20th	Day	18% 6% 23% 28% 17% 8%	479
	21st to end	Day	17% 7% 24% 25% 16% 10%	539
September	1st to 10th	Day	19% 10% 21% 25% 18% 8%	490
	11th to 20th	Day	17% 7% 23% 24% 20% 11%	490
	21st to end	Day	29% 11% 22% 20% 14% 4	490
October	1st to 10th	Day	28% 9% 22% 22% 13% 6%	490
	11th to 20th	Day	26% 16% 28% 21% 8% 2	462
	21st to end	Day	31% 13% 28% 21% 6% 1	495
November	1st to 10th	Day	24% 14% 27% 23% 12% 1	368
	11th to 20th	Day	29% 21% 26% 17% 6% 1	262
	21st to end	Day	28% 20% 36% 13% 3	180
December	1st to 10th	Day	31% 22% 33% 12% 2 1	180
	11th to 20th	Day	38% 17% 31% 12% 2 1	180
	21st to end	Day	37% 20% 28% 13% 3	198
January	1st to 10th	Night	24% 18% 37% 18% 3	760
	11th to 20th	Night	27% 17% 29% 24% 3	760
	21st to end	Night	23% 21% 32% 22% 2	836
February	1st to 10th	Night	26% 19% 31% 23% 2	760
	11th to 20th	Night	27% 21% 35% 16% 1	743
	21st to end	Night	30% 18% 31% 18% 3	628
March	1st to 10th	Night	26% 21% 29% 20% 4	760
	11th to 20th	Night	27% 19% 27% 22% 5%	760
	21st to end	Night	24% 20% 31% 18% 6% 1	836
April	1st to 10th	Night	29% 19% 27% 22% 4	760
	11th to 20th	Night	23% 17% 29% 24% 7% 1	751
	21st to end	Night	22% 15% 28% 28% 7%	743
May	1st to 10th	Night	30% 9% 19% 28% 13% 1	523
	11th to 20th	Night	19% 11% 27% 33% 10% 1	374
	21st to end	Night	18% 7% 19% 35% 20% 1	411
June	1st to 10th	Night	16% 7% 19% 42% 16% 1	380
	11th to 20th	Night	14% 8% 21% 40% 16%	380
	21st to end	Night	14% 4 21% 44% 15% 1	380
July	1st to 10th	Night	12% 6% 19% 42% 20% 2	370
	11th to 20th	Night	11% 4 12% 47% 24% 2	368
	21st to end	Night	15% 2 14% 43% 24% 2	535
August	1st to 10th	Night	15% 3 13% 41% 26% 3	567
	11th to 20th	Night	16% 5% 12% 35% 29% 3	597
	21st to end	Night	14% 5% 17% 34% 28% 3	836
September	1st to 10th	Night	18% 6% 19% 35% 20% 2	760
	11th to 20th	Night	16% 5% 17% 30% 27% 5%	760
	21st to end	Night	23% 8% 18% 30% 18% 3	760
October	1st to 10th	Night	24% 9% 17% 28% 19% 3	760
	11th to 20th	Night	22% 12% 24% 31% 9% 1	735
	21st to end	Night	29% 13% 24% 29% 5%	792
November	1st to 10th	Night	18% 12% 29% 32% 10%	740
	11th to 20th	Night	27% 15% 25% 24% 6% 2	760
	21st to end	Night	22% 16% 29% 28% 5% 1	760
December	1st to 10th	Night	30% 16% 29% 20% 4	760
	11th to 20th	Night	26% 16% 29% 25% 4	760
	21st to end	Night	29% 17% 28% 23% 2	836

Page generated at 2024-10-11 10:49:59. Version ac07

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