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 2005-11-06 to 2024-02-10.

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% 9% 4 7% 6% 4 5% 5% 5% 7% 33%	78256
	Night	18% 9% 3 6% 6% 3 5% 5% 5% 7% 34%	80704
Transparency	Day	51% 5% 11% 20% 11% 2	77968
	Night	50% 4 12% 21% 11% 1	80526
Seeing	Day	25% 15% 27% 20% 10% 4	13700
	Night	23% 13% 25% 28% 10% 1	23202

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% 7% 7% 3 5% 3 4 5% 28%	2517
	11th to 20th	Day	14% 15% 9% 14% 8% 4 5% 3 3 5% 20%	2684
	21st to end	Day	21% 16% 8% 10% 6% 4 4 4 4 5% 19%	3124
February	1st to 10th	Day	16% 15% 5% 8% 7% 4 5% 5% 5% 5% 25%	1701
	11th to 20th	Day	15% 11% 6% 8% 8% 5% 5% 4 5% 6% 28%	1587
	21st to end	Day	20% 12% 6% 9% 6% 3 4 3 5% 5% 29%	1480
March	1st to 10th	Day	15% 9% 5% 8% 7% 3 4 4 5% 5% 35%	1900
	11th to 20th	Day	17% 9% 4 9% 6% 3 5% 4 4 7% 32%	1980
	21st to end	Day	20% 9% 4 6% 6% 3 4 4 4 5% 32%	2231
April	1st to 10th	Day	18% 9% 4 6% 7% 4 4 4 5% 6% 33%	2160
	11th to 20th	Day	19% 9% 3 6% 5% 3 4 5% 5% 6% 34%	2134
	21st to end	Day	20% 8% 3 5% 6% 4 5% 4 5% 6% 35%	2190
May	1st to 10th	Day	21% 7% 3 6% 6% 3 5% 5% 5% 6% 32%	2384
	11th to 20th	Day	21% 7% 3 7% 5% 3 4 5% 5% 6% 32%	2478
	21st to end	Day	17% 6% 2 5% 5% 4 5% 5% 5% 7% 39%	2725
June	1st to 10th	Day	16% 5% 4 6% 7% 5% 6% 5% 5% 8% 35%	2520
	11th to 20th	Day	17% 6% 3 6% 6% 3 5% 5% 6% 8% 35%	2520
	21st to end	Day	14% 5% 3 5% 6% 4 6% 6% 6% 9% 37%	2520
July	1st to 10th	Day	11% 6% 3 6% 7% 5% 6% 7% 6% 9% 36%	2520
	11th to 20th	Day	10% 5% 3 5% 6% 3 6% 6% 8% 10% 38%	2520
	21st to end	Day	12% 6% 3 6% 7% 4 6% 6% 5% 8% 37%	2629
August	1st to 10th	Day	13% 6% 3 6% 6% 5% 6% 7% 7% 9% 33%	2327
	11th to 20th	Day	14% 6% 3 6% 8% 4 6% 6% 7% 8% 33%	2254
	21st to end	Day	16% 5% 3 5% 6% 4 5% 7% 6% 8% 34%	2376
September	1st to 10th	Day	19% 5% 2 5% 5% 3 5% 5% 5% 6% 39%	2160
	11th to 20th	Day	16% 5% 2 4 5% 2 4 6% 4 5% 47%	2160
	21st to end	Day	22% 6% 2 5% 4 3 4 4 5% 7% 37%	1899
October	1st to 10th	Day	20% 8% 2 4 6% 3 3 4 5% 7% 39%	1800
	11th to 20th	Day	22% 7% 3 5% 5% 3 4 5% 6% 7% 33%	1800
	21st to end	Day	23% 8% 3 6% 6% 3 5% 6% 5% 6% 30%	1980
November	1st to 10th	Day	15% 6% 3 6% 5% 3 5% 4 4 7% 42%	1676
	11th to 20th	Day	18% 10% 3 6% 5% 3 4 4 6% 5% 34%	1602
	21st to end	Day	18% 11% 4 6% 6% 3 4 5% 6% 6% 32%	1520
December	1st to 10th	Day	22% 14% 6% 8% 7% 3 5% 3 4 5% 23%	1520
	11th to 20th	Day	23% 11% 5% 6% 6% 3 4 4 5% 6% 28%	1906
	21st to end	Day	24% 16% 4 8% 7% 4 5% 4 3 5% 19%	2772
January	1st to 10th	Night	17% 12% 4 7% 6% 3 5% 5% 5% 6% 29%	4429
	11th to 20th	Night	16% 14% 6% 12% 7% 3 4 4 5% 5% 24%	4273
	21st to end	Night	24% 12% 5% 9% 8% 4 5% 4 4 4 21%	4532
February	1st to 10th	Night	17% 11% 5% 7% 5% 4 6% 4 6% 6% 30%	2464
	11th to 20th	Night	16% 10% 4 7% 7% 3 6% 5% 5% 7% 30%	2258
	21st to end	Night	18% 11% 4 9% 6% 3 5% 4 5% 5% 29%	1776
March	1st to 10th	Night	15% 8% 3 7% 5% 4 6% 5% 7% 7% 34%	2043
	11th to 20th	Night	18% 9% 3 5% 7% 3 4 5% 5% 6% 36%	1979
	21st to end	Night	16% 9% 3 7% 6% 4 5% 4 4 6% 35%	2124
April	1st to 10th	Night	20% 12% 5% 7% 4 3 4 4 4 6% 32%	1800
	11th to 20th	Night	18% 8% 2 5% 5% 3 4 6% 5% 7% 37%	1775
	21st to end	Night	18% 7% 2 5% 5% 2 5% 4 5% 7% 39%	1784
May	1st to 10th	Night	24% 8% 2 5% 5% 3 4 4 5% 6% 35%	1576
	11th to 20th	Night	18% 5% 2 5% 5% 3 6% 5% 5% 6% 39%	1415
	21st to end	Night	16% 4 3 5% 5% 3 5% 4 5% 8% 41%	1550
June	1st to 10th	Night	16% 6% 2 5% 6% 2 4 5% 4 9% 42%	1440
	11th to 20th	Night	14% 6% 3 5% 4 4 5% 6% 7% 8% 38%	1440
	21st to end	Night	13% 5% 2 5% 6% 3 4 4 7% 9% 42%	1440
July	1st to 10th	Night	11% 6% 3 5% 5% 2 4 5% 7% 8% 43%	1440
	11th to 20th	Night	9% 5% 2 5% 5% 3 4 5% 7% 9% 45%	1440
	21st to end	Night	12% 5% 3 5% 4 3 5% 5% 7% 8% 42%	1686
August	1st to 10th	Night	12% 5% 1 4 5% 3 5% 5% 7% 9% 43%	1611
	11th to 20th	Night	13% 6% 3 7% 6% 3 5% 4 6% 7% 40%	1629
	21st to end	Night	15% 4 3 5% 5% 3 4 4 6% 7% 43%	1980
September	1st to 10th	Night	17% 6% 3 4 5% 2 5% 4 5% 6% 43%	1800
	11th to 20th	Night	15% 5% 2 4 3 2 3 4 4 7% 50%	1800
	21st to end	Night	18% 5% 2 4 5% 3 4 4 5% 7% 43%	2057
October	1st to 10th	Night	20% 7% 2 5% 4 3 5% 4 4 6% 41%	2160
	11th to 20th	Night	20% 7% 2 4 4 2 4 5% 4 7% 39%	2160
	21st to end	Night	23% 9% 2 6% 4 2 4 4 5% 7% 34%	2376
November	1st to 10th	Night	13% 8% 3 5% 5% 2 4 3 5% 7% 45%	2401
	11th to 20th	Night	20% 8% 3 6% 5% 3 5% 6% 5% 6% 32%	2574
	21st to end	Night	17% 9% 4 7% 6% 3 5% 5% 5% 7% 32%	2660
December	1st to 10th	Night	21% 12% 5% 6% 6% 4 5% 5% 6% 7% 25%	2660
	11th to 20th	Night	20% 11% 4 8% 7% 4 4 5% 5% 5% 28%	3288
	21st to end	Night	23% 12% 5% 7% 7% 4 4 5% 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	61% 4 10% 16% 8% 1	1701
	11th to 20th	Day	58% 4 8% 21% 8% 1	1596
	21st to end	Day	59% 2 8% 20% 8% 2	1480
March	1st to 10th	Day	52% 4 11% 23% 9% 2	1903
	11th to 20th	Day	54% 4 9% 20% 11% 3	1980
	21st to end	Day	54% 3 8% 19% 13% 2	2231
April	1st to 10th	Day	52% 4 9% 21% 12% 3	2160
	11th to 20th	Day	50% 4 11% 18% 15% 2	2134
	21st to end	Day	50% 4 8% 20% 14% 4	2190
May	1st to 10th	Day	52% 5% 9% 19% 13% 2	2384
	11th to 20th	Day	52% 4 10% 19% 12% 2	2482
	21st to end	Day	44% 6% 14% 22% 12% 2	2725
June	1st to 10th	Day	47% 6% 13% 20% 13% 1	2520
	11th to 20th	Day	46% 6% 14% 20% 12% 2	2520
	21st to end	Day	42% 6% 13% 27% 12%	2520
July	1st to 10th	Day	43% 7% 12% 24% 13% 1	2450
	11th to 20th	Day	38% 7% 16% 26% 13% 1	2445
	21st to end	Day	43% 7% 12% 22% 14% 2	2482
August	1st to 10th	Day	44% 7% 13% 23% 13%	2314
	11th to 20th	Day	46% 7% 13% 23% 10% 1	2254
	21st to end	Day	45% 6% 11% 21% 14% 3	2376
September	1st to 10th	Day	44% 6% 11% 24% 14% 2	2160
	11th to 20th	Day	38% 5% 11% 25% 20% 2	2160
	21st to end	Day	46% 4 13% 20% 16% 2	1899
October	1st to 10th	Day	46% 5% 11% 23% 14% 1	1800
	11th to 20th	Day	50% 4 11% 24% 10%	1800
	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	54% 4 12% 20% 9%	2464
	11th to 20th	Night	54% 4 10% 20% 11% 2	2260
	21st to end	Night	58% 3 8% 18% 11% 2	1776
March	1st to 10th	Night	48% 5% 11% 25% 10% 2	2053
	11th to 20th	Night	50% 4 11% 21% 12% 2	1980
	21st to end	Night	52% 3 10% 17% 16% 3	2124
April	1st to 10th	Night	54% 4 9% 19% 13% 2	1800
	11th to 20th	Night	45% 5% 11% 21% 15% 2	1775
	21st to end	Night	46% 3 10% 23% 15% 3	1784
May	1st to 10th	Night	50% 4 11% 22% 10% 3	1576
	11th to 20th	Night	45% 5% 11% 20% 17% 2	1416
	21st to end	Night	41% 7% 14% 21% 14% 3	1551
June	1st to 10th	Night	41% 5% 12% 26% 15% 2	1440
	11th to 20th	Night	42% 6% 14% 24% 13% 2	1440
	21st to end	Night	38% 6% 12% 29% 14% 1	1440
July	1st to 10th	Night	38% 7% 12% 26% 14% 2	1400
	11th to 20th	Night	34% 7% 15% 25% 18% 1	1392
	21st to end	Night	36% 7% 16% 23% 16% 2	1592
August	1st to 10th	Night	35% 8% 15% 27% 13% 1	1600
	11th to 20th	Night	43% 6% 14% 23% 13% 1	1629
	21st to end	Night	40% 6% 12% 25% 16% 2	1980
September	1st to 10th	Night	41% 5% 10% 27% 15% 3	1800
	11th to 20th	Night	35% 4 12% 28% 20% 2	1800
	21st to end	Night	42% 4 11% 25% 17% 1	2057
October	1st to 10th	Night	45% 5% 12% 24% 15% 1	2160
	11th to 20th	Night	45% 6% 12% 24% 12% 2	2160
	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% 26% 31% 10% 2	267
	11th to 20th	Day	37% 24% 34% 4	254
	21st to end	Day	36% 21% 27% 14% 2	346
March	1st to 10th	Day	31% 21% 29% 17% 3	420
	11th to 20th	Day	29% 25% 27% 14% 4 1	420
	21st to end	Day	32% 22% 24% 14% 5% 2	462
April	1st to 10th	Day	30% 23% 27% 15% 5% 1	420
	11th to 20th	Day	24% 26% 20% 17% 9% 3	412
	21st to end	Day	29% 20% 30% 13% 6% 2	420
May	1st to 10th	Day	33% 16% 23% 16% 8% 3	423
	11th to 20th	Day	26% 17% 26% 19% 9% 4	447
	21st to end	Day	22% 10% 25% 21% 16% 6%	485
June	1st to 10th	Day	18% 14% 30% 23% 13% 2	450
	11th to 20th	Day	18% 13% 28% 24% 14% 2	450
	21st to end	Day	18% 10% 33% 24% 12% 4	450
July	1st to 10th	Day	14% 6% 24% 30% 20% 6%	445
	11th to 20th	Day	11% 8% 28% 29% 19% 5%	444
	21st to end	Day	15% 8% 28% 29% 14% 5%	488
August	1st to 10th	Day	12% 6% 25% 28% 22% 7%	446
	11th to 20th	Day	17% 6% 22% 28% 18% 8%	439
	21st to end	Day	17% 7% 25% 24% 17% 10%	495
September	1st to 10th	Day	20% 8% 21% 25% 18% 8%	450
	11th to 20th	Day	18% 7% 24% 22% 19% 10%	450
	21st to end	Day	24% 12% 23% 22% 15% 4	450
October	1st to 10th	Day	28% 8% 22% 22% 14% 6%	450
	11th to 20th	Day	26% 16% 27% 21% 8% 2	450
	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	759
	11th to 20th	Night	27% 21% 35% 16% 1	703
	21st to end	Night	31% 19% 31% 18% 2	592
March	1st to 10th	Night	25% 21% 29% 21% 3	720
	11th to 20th	Night	28% 18% 28% 22% 5%	720
	21st to end	Night	23% 20% 32% 18% 6% 1	792
April	1st to 10th	Night	29% 19% 27% 22% 4	720
	11th to 20th	Night	22% 17% 30% 24% 7% 1	711
	21st to end	Night	23% 14% 28% 28% 7%	704
May	1st to 10th	Night	30% 9% 19% 28% 14% 1	496
	11th to 20th	Night	18% 11% 28% 32% 10% 1	354
	21st to end	Night	18% 7% 19% 34% 21% 1	389
June	1st to 10th	Night	16% 7% 19% 41% 16% 1	360
	11th to 20th	Night	15% 8% 21% 39% 16%	360
	21st to end	Night	13% 4 21% 46% 15% 1	360
July	1st to 10th	Night	12% 5% 18% 42% 21% 2	350
	11th to 20th	Night	11% 5% 11% 46% 25% 3	348
	21st to end	Night	15% 3 14% 43% 23% 2	506
August	1st to 10th	Night	14% 3 13% 41% 26% 3	537
	11th to 20th	Night	16% 4 12% 34% 30% 3	565
	21st to end	Night	14% 5% 17% 34% 28% 3	792
September	1st to 10th	Night	19% 5% 18% 36% 20% 2	720
	11th to 20th	Night	17% 5% 17% 30% 25% 6%	720
	21st to end	Night	20% 8% 19% 32% 19% 3	720
October	1st to 10th	Night	25% 9% 17% 29% 18% 3	720
	11th to 20th	Night	22% 12% 24% 31% 10% 1	720
	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 2024-02-07 06:11:56. Version ac07

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