Scranton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Scranton clear sky chart from 2005-11-06 to 2024-03-06.

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% 9% 4 7% 6% 3 5% 5% 5% 7% 33%	78462
	Night	17% 10% 4 7% 6% 3 4 4 5% 6% 34%	81047
Transparency	Day	51% 5% 11% 21% 11% 1	78168
	Night	50% 5% 12% 21% 11% 1	80875
Seeing	Day	25% 18% 28% 18% 9% 3	13872
	Night	22% 16% 28% 24% 9% 1	23274

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	14% 14% 11% 9% 6% 3 4 3 3 4 29%	2517
	11th to 20th	Day	14% 14% 8% 11% 7% 4 5% 5% 4 5% 23%	2530
	21st to end	Day	22% 16% 7% 8% 7% 2 4 4 4 5% 21%	3124
February	1st to 10th	Day	16% 11% 3 9% 8% 5% 6% 6% 5% 7% 25%	1710
	11th to 20th	Day	14% 11% 5% 7% 6% 4 5% 5% 5% 7% 30%	1752
	21st to end	Day	18% 11% 4 8% 7% 3 5% 4 5% 6% 29%	1570
March	1st to 10th	Day	15% 10% 6% 8% 7% 3 5% 4 4 7% 32%	1865
	11th to 20th	Day	16% 11% 5% 8% 7% 3 5% 4 5% 6% 31%	1980
	21st to end	Day	19% 10% 5% 7% 6% 3 4 5% 5% 6% 31%	2289
April	1st to 10th	Day	18% 11% 4 5% 5% 4 5% 4 4 5% 35%	2160
	11th to 20th	Day	17% 9% 3 5% 6% 3 4 5% 4 7% 36%	2134
	21st to end	Day	18% 9% 3 6% 5% 4 4 5% 6% 6% 34%	2160
May	1st to 10th	Day	21% 9% 3 5% 5% 4 6% 5% 5% 7% 31%	2402
	11th to 20th	Day	20% 7% 3 5% 7% 4 5% 5% 5% 7% 33%	2478
	21st to end	Day	15% 8% 2 5% 5% 3 5% 5% 5% 8% 38%	2725
June	1st to 10th	Day	17% 5% 3 6% 6% 4 6% 4 6% 9% 34%	2520
	11th to 20th	Day	15% 7% 4 6% 6% 4 6% 5% 6% 9% 32%	2520
	21st to end	Day	14% 6% 2 5% 6% 3 6% 5% 7% 9% 36%	2520
July	1st to 10th	Day	12% 6% 3 5% 7% 4 6% 5% 7% 9% 35%	2520
	11th to 20th	Day	10% 5% 2 6% 6% 3 5% 6% 7% 10% 39%	2520
	21st to end	Day	11% 6% 3 6% 7% 4 6% 5% 6% 8% 37%	2734
August	1st to 10th	Day	13% 7% 2 5% 6% 4 6% 6% 7% 9% 34%	2327
	11th to 20th	Day	15% 6% 3 7% 7% 4 5% 5% 5% 8% 35%	2185
	21st to end	Day	15% 7% 3 6% 6% 3 5% 5% 6% 8% 36%	2376
September	1st to 10th	Day	17% 5% 3 6% 6% 3 4 5% 6% 7% 37%	2160
	11th to 20th	Day	14% 5% 3 5% 5% 3 5% 4 5% 7% 45%	2152
	21st to end	Day	17% 6% 3 6% 5% 3 4 5% 6% 7% 37%	1944
October	1st to 10th	Day	18% 8% 2 5% 5% 3 4 5% 5% 8% 37%	1800
	11th to 20th	Day	17% 8% 3 6% 6% 3 4 5% 5% 7% 36%	1800
	21st to end	Day	23% 9% 4 6% 5% 3 5% 4 5% 7% 29%	1908
November	1st to 10th	Day	14% 10% 3 6% 5% 3 4 4 4 6% 41%	1671
	11th to 20th	Day	16% 12% 3 8% 5% 2 5% 4 5% 6% 35%	1691
	21st to end	Day	18% 11% 3 7% 6% 3 4 5% 5% 6% 31%	1520
December	1st to 10th	Day	19% 13% 5% 7% 7% 4 4 4 5% 7% 25%	1520
	11th to 20th	Day	20% 13% 6% 8% 5% 3 4 4 4 5% 28%	1906
	21st to end	Day	22% 16% 6% 9% 7% 3 5% 4 4 4 19%	2772
January	1st to 10th	Night	15% 12% 6% 9% 7% 4 4 4 4 6% 29%	4429
	11th to 20th	Night	13% 15% 6% 12% 8% 4 4 4 4 5% 25%	4426
	21st to end	Night	24% 12% 6% 9% 9% 3 4 4 4 4 20%	4532
February	1st to 10th	Night	16% 11% 5% 9% 6% 3 5% 4 4 7% 30%	2470
	11th to 20th	Night	14% 12% 5% 8% 7% 3 6% 6% 5% 6% 28%	2313
	21st to end	Night	18% 11% 4 9% 6% 4 4 4 4 5% 32%	1884
March	1st to 10th	Night	16% 11% 5% 7% 5% 4 4 4 6% 6% 32%	2198
	11th to 20th	Night	15% 10% 5% 7% 5% 3 5% 5% 4 6% 35%	1979
	21st to end	Night	16% 11% 3 6% 6% 3 5% 4 4 6% 36%	2066
April	1st to 10th	Night	17% 11% 5% 7% 6% 3 4 5% 4 6% 31%	1800
	11th to 20th	Night	17% 8% 2 5% 6% 3 4 4 4 7% 39%	1775
	21st to end	Night	20% 8% 3 5% 5% 3 4 4 5% 5% 38%	1800
May	1st to 10th	Night	22% 9% 3 6% 5% 3 4 4 4 5% 33%	1570
	11th to 20th	Night	15% 7% 3 5% 5% 4 7% 4 6% 7% 38%	1415
	21st to end	Night	12% 7% 3 6% 6% 3 4 6% 5% 8% 39%	1550
June	1st to 10th	Night	17% 5% 3 5% 4 3 5% 5% 6% 8% 39%	1440
	11th to 20th	Night	15% 6% 3 7% 5% 2 5% 5% 6% 8% 39%	1440
	21st to end	Night	13% 4 2 4 5% 2 4 5% 6% 9% 45%	1440
July	1st to 10th	Night	13% 5% 3 5% 5% 3 5% 6% 5% 9% 42%	1440
	11th to 20th	Night	11% 5% 3 5% 5% 3 5% 6% 6% 10% 42%	1440
	21st to end	Night	12% 6% 2 4 5% 3 6% 5% 5% 8% 43%	1581
August	1st to 10th	Night	11% 5% 2 5% 5% 3 5% 6% 7% 9% 41%	1611
	11th to 20th	Night	13% 6% 3 6% 7% 3 5% 5% 7% 8% 37%	1696
	21st to end	Night	13% 5% 3 5% 6% 3 4 4 5% 8% 44%	1980
September	1st to 10th	Night	16% 5% 3 5% 5% 3 5% 5% 6% 6% 42%	1800
	11th to 20th	Night	14% 6% 3 4 4 2 4 4 4 6% 50%	1808
	21st to end	Night	16% 6% 2 5% 5% 3 4 4 5% 7% 42%	2011
October	1st to 10th	Night	20% 6% 2 5% 4 3 4 4 5% 7% 41%	2160
	11th to 20th	Night	17% 7% 3 5% 5% 3 5% 4 5% 4 42%	2160
	21st to end	Night	23% 9% 2 5% 4 3 4 4 6% 7% 33%	2446
November	1st to 10th	Night	13% 9% 3 6% 5% 3 4 3 4 5% 44%	2407
	11th to 20th	Night	18% 10% 3 7% 5% 3 4 4 5% 6% 36%	2488
	21st to end	Night	14% 11% 4 5% 5% 3 5% 5% 6% 7% 35%	2660
December	1st to 10th	Night	20% 11% 5% 8% 6% 4 5% 5% 6% 6% 25%	2660
	11th to 20th	Night	18% 14% 5% 8% 5% 3 5% 5% 4 6% 28%	3288
	21st to end	Night	24% 15% 6% 8% 5% 3 4 4 4 6% 24%	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	59% 4 10% 21% 5% 1	2518
	11th to 20th	Day	66% 4 8% 16% 5% 1	2530
	21st to end	Day	65% 3 10% 16% 5% 1	3124
February	1st to 10th	Day	59% 5% 11% 16% 9% 1	1710
	11th to 20th	Day	54% 5% 8% 22% 10% 1	1761
	21st to end	Day	57% 4 9% 20% 8% 2	1570
March	1st to 10th	Day	54% 4 12% 20% 9% 2	1868
	11th to 20th	Day	54% 4 8% 21% 12% 1	1980
	21st to end	Day	55% 4 7% 17% 14% 2	2289
April	1st to 10th	Day	53% 4 8% 21% 10% 3	2160
	11th to 20th	Day	48% 5% 10% 23% 13% 2	2134
	21st to end	Day	49% 4 9% 22% 12% 4	2160
May	1st to 10th	Day	54% 5% 8% 19% 12% 3	2402
	11th to 20th	Day	51% 6% 9% 20% 12% 2	2482
	21st to end	Day	44% 6% 15% 20% 12% 2	2725
June	1st to 10th	Day	48% 5% 13% 21% 12% 1	2520
	11th to 20th	Day	49% 5% 13% 21% 10% 1	2520
	21st to end	Day	44% 6% 13% 26% 11%	2520
July	1st to 10th	Day	45% 6% 13% 22% 13% 1	2450
	11th to 20th	Day	37% 6% 16% 26% 14% 1	2445
	21st to end	Day	43% 6% 13% 21% 15% 2	2581
August	1st to 10th	Day	45% 6% 14% 23% 11%	2314
	11th to 20th	Day	47% 6% 14% 23% 10%	2185
	21st to end	Day	46% 4 11% 23% 14% 2	2376
September	1st to 10th	Day	46% 5% 12% 21% 14% 1	2160
	11th to 20th	Day	39% 4 11% 22% 21% 2	2152
	21st to end	Day	45% 5% 10% 23% 16% 2	1944
October	1st to 10th	Day	46% 5% 12% 22% 13% 2	1800
	11th to 20th	Day	47% 5% 11% 24% 13% 1	1800
	21st to end	Day	55% 4 12% 18% 9% 2	1908
November	1st to 10th	Day	44% 4 12% 24% 14% 3	1671
	11th to 20th	Day	51% 4 10% 21% 13% 2	1691
	21st to end	Day	53% 4 14% 21% 7% 1	1520
December	1st to 10th	Day	58% 5% 16% 13% 7% 1	1520
	11th to 20th	Day	59% 4 15% 17% 5%	1906
	21st to end	Day	68% 4 10% 13% 5%	2772
January	1st to 10th	Night	56% 5% 11% 21% 6% 1	4429
	11th to 20th	Night	62% 5% 10% 17% 6% 1	4426
	21st to end	Night	68% 4 7% 15% 6%	4532
February	1st to 10th	Night	54% 5% 12% 20% 9% 1	2470
	11th to 20th	Night	57% 5% 10% 17% 9% 1	2315
	21st to end	Night	55% 4 8% 20% 11% 2	1884
March	1st to 10th	Night	53% 4 11% 19% 10% 2	2208
	11th to 20th	Night	50% 4 12% 21% 11% 1	1980
	21st to end	Night	51% 4 9% 17% 17% 3	2066
April	1st to 10th	Night	55% 4 9% 19% 12% 2	1800
	11th to 20th	Night	46% 5% 11% 21% 16% 1	1775
	21st to end	Night	48% 5% 10% 21% 14% 3	1800
May	1st to 10th	Night	55% 4 9% 20% 10% 3	1570
	11th to 20th	Night	44% 7% 10% 22% 15% 2	1416
	21st to end	Night	42% 7% 16% 22% 11% 2	1551
June	1st to 10th	Night	43% 5% 11% 26% 14%	1440
	11th to 20th	Night	41% 6% 16% 26% 10% 1	1440
	21st to end	Night	36% 6% 15% 29% 13%	1440
July	1st to 10th	Night	39% 7% 15% 24% 14% 2	1400
	11th to 20th	Night	36% 8% 17% 28% 11% 1	1392
	21st to end	Night	36% 8% 17% 22% 15% 2	1493
August	1st to 10th	Night	38% 6% 16% 28% 12% 1	1600
	11th to 20th	Night	42% 7% 16% 22% 12%	1696
	21st to end	Night	39% 6% 12% 24% 18% 1	1980
September	1st to 10th	Night	41% 6% 13% 24% 15% 1	1800
	11th to 20th	Night	36% 4 10% 26% 22% 2	1808
	21st to end	Night	41% 4 9% 25% 18% 1	2011
October	1st to 10th	Night	44% 4 12% 24% 15% 1	2160
	11th to 20th	Night	44% 5% 14% 25% 11% 1	2160
	21st to end	Night	50% 5% 13% 21% 11% 1	2446
November	1st to 10th	Night	43% 4 12% 22% 17% 3	2407
	11th to 20th	Night	49% 4 11% 21% 12% 3	2488
	21st to end	Night	48% 5% 14% 23% 9% 1	2660
December	1st to 10th	Night	59% 6% 11% 18% 6%	2660
	11th to 20th	Night	57% 6% 12% 17% 8% 1	3288
	21st to end	Night	63% 4 11% 18% 4	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	34% 25% 28% 9% 2 1	180
	11th to 20th	Day	42% 25% 25% 6% 2	185
	21st to end	Day	30% 30% 28% 8% 3 1	297
February	1st to 10th	Day	36% 29% 28% 7%	270
	11th to 20th	Day	36% 27% 29% 7% 1	359
	21st to end	Day	35% 28% 26% 8% 3	382
March	1st to 10th	Day	31% 24% 30% 12% 3	440
	11th to 20th	Day	31% 25% 26% 13% 4 1	420
	21st to end	Day	35% 23% 25% 10% 4 2	462
April	1st to 10th	Day	32% 24% 26% 12% 5%	420
	11th to 20th	Day	28% 22% 29% 12% 7% 2	412
	21st to end	Day	28% 24% 30% 12% 4 2	420
May	1st to 10th	Day	35% 18% 28% 9% 7% 3	423
	11th to 20th	Day	25% 17% 33% 15% 7% 2	447
	21st to end	Day	19% 12% 29% 24% 12% 3	485
June	1st to 10th	Day	20% 15% 29% 23% 10% 3	450
	11th to 20th	Day	20% 17% 25% 24% 13% 1	450
	21st to end	Day	18% 12% 33% 27% 8% 1	450
July	1st to 10th	Day	16% 7% 27% 28% 17% 5%	445
	11th to 20th	Day	9% 7% 31% 32% 17% 4	444
	21st to end	Day	14% 10% 34% 28% 9% 4	488
August	1st to 10th	Day	13% 8% 27% 26% 19% 7%	446
	11th to 20th	Day	15% 8% 26% 29% 16% 6%	439
	21st to end	Day	13% 11% 28% 25% 15% 7%	495
September	1st to 10th	Day	20% 12% 21% 21% 18% 8%	450
	11th to 20th	Day	15% 9% 27% 21% 17% 11%	450
	21st to end	Day	24% 12% 26% 21% 13% 4	450
October	1st to 10th	Day	26% 13% 23% 19% 13% 6%	450
	11th to 20th	Day	23% 17% 30% 21% 8% 1	450
	21st to end	Day	30% 18% 30% 16% 6% 1	459
November	1st to 10th	Day	24% 20% 22% 23% 9% 1	365
	11th to 20th	Day	32% 22% 28% 15% 4 1	351
	21st to end	Day	38% 21% 31% 9% 2	180
December	1st to 10th	Day	36% 26% 26% 8% 3 1	180
	11th to 20th	Day	39% 23% 27% 8% 2	180
	21st to end	Day	31% 29% 28% 10% 2 1	198
January	1st to 10th	Night	24% 26% 34% 12% 3	760
	11th to 20th	Night	28% 23% 29% 18% 3	760
	21st to end	Night	21% 28% 33% 15% 2	836
February	1st to 10th	Night	28% 22% 33% 16% 1	760
	11th to 20th	Night	28% 28% 32% 11% 1	743
	21st to end	Night	29% 25% 30% 14% 2	628
March	1st to 10th	Night	28% 23% 29% 17% 3	743
	11th to 20th	Night	28% 21% 31% 16% 4	720
	21st to end	Night	25% 21% 32% 16% 6%	792
April	1st to 10th	Night	24% 23% 30% 20% 2	720
	11th to 20th	Night	24% 20% 30% 19% 7%	711
	21st to end	Night	27% 17% 27% 25% 5%	720
May	1st to 10th	Night	28% 12% 27% 24% 9%	490
	11th to 20th	Night	17% 10% 36% 29% 6% 1	354
	21st to end	Night	13% 9% 26% 37% 15%	389
June	1st to 10th	Night	16% 8% 23% 38% 14%	360
	11th to 20th	Night	14% 9% 27% 39% 11%	360
	21st to end	Night	13% 5% 25% 47% 9% 1	360
July	1st to 10th	Night	13% 5% 21% 38% 22% 1	350
	11th to 20th	Night	12% 5% 19% 44% 18% 2	348
	21st to end	Night	14% 7% 18% 42% 17% 1	401
August	1st to 10th	Night	12% 3 20% 44% 18% 3	537
	11th to 20th	Night	16% 3 15% 36% 28% 2	632
	21st to end	Night	16% 5% 18% 36% 24% 1	792
September	1st to 10th	Night	17% 6% 22% 35% 17% 3	720
	11th to 20th	Night	16% 7% 21% 30% 21% 6%	720
	21st to end	Night	20% 9% 22% 29% 18% 3	720
October	1st to 10th	Night	24% 9% 22% 26% 17% 1	720
	11th to 20th	Night	19% 15% 29% 30% 8%	720
	21st to end	Night	28% 15% 29% 22% 6%	792
November	1st to 10th	Night	18% 18% 31% 24% 7% 1	740
	11th to 20th	Night	25% 21% 28% 19% 6% 1	760
	21st to end	Night	23% 22% 31% 19% 5% 1	760
December	1st to 10th	Night	29% 21% 30% 15% 4	760
	11th to 20th	Night	26% 25% 28% 18% 3	760
	21st to end	Night	28% 22% 33% 16% 2	836

Page generated at 2024-03-03 06:28:56. Version ac07

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