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 2024-11-02.

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% 10% 3 7% 5% 5% 4 4 5% 7% 33%	101397
	Night	17% 10% 3 8% 5% 4 4 3 5% 6% 34%	97556
Transparency	Day	50% 5% 12% 21% 11% 1	101155
	Night	50% 5% 12% 21% 11% 1	97417
Seeing	Day	25% 18% 28% 18% 9% 3	14831
	Night	22% 16% 27% 24% 9% 1	24045

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% 15% 10% 9% 5% 5% 3 2 3 4 29%	2517
	11th to 20th	Day	14% 15% 8% 12% 6% 5% 5% 4 4 5% 22%	2530
	21st to end	Day	22% 17% 6% 9% 7% 4 3 3 4 5% 21%	3124
February	1st to 10th	Day	16% 12% 3 11% 7% 6% 6% 4 5% 6% 25%	1710
	11th to 20th	Day	14% 12% 5% 8% 6% 5% 4 4 6% 7% 30%	1752
	21st to end	Day	18% 12% 3 9% 6% 5% 4 3 5% 6% 28%	1570
March	1st to 10th	Day	25% 14% 4 7% 5% 4 3 3 3 5% 27%	3148
	11th to 20th	Day	12% 14% 4 8% 6% 5% 4 3 5% 6% 35%	3480
	21st to end	Day	20% 10% 3 6% 4 4 3 3 4 6% 36%	4023
April	1st to 10th	Day	19% 12% 3 7% 4 5% 4 3 4 5% 33%	2280
	11th to 20th	Day	16% 11% 3 6% 5% 4 4 4 5% 6% 36%	2254
	21st to end	Day	17% 10% 3 6% 5% 5% 4 4 6% 6% 35%	2280
May	1st to 10th	Day	28% 8% 2 5% 4 4 4 3 5% 6% 30%	4225
	11th to 20th	Day	24% 9% 3 7% 6% 5% 4 4 5% 7% 26%	4398
	21st to end	Day	15% 6% 2 5% 4 4 5% 4 7% 9% 41%	4837
June	1st to 10th	Day	16% 6% 3 6% 6% 5% 5% 4 6% 9% 33%	2660
	11th to 20th	Day	14% 8% 3 7% 5% 5% 5% 4 7% 8% 33%	2660
	21st to end	Day	14% 6% 2 7% 5% 5% 5% 4 7% 9% 35%	2660
July	1st to 10th	Day	8% 6% 3 8% 6% 5% 6% 5% 8% 11% 35%	4440
	11th to 20th	Day	8% 7% 2 8% 5% 5% 5% 4 8% 11% 36%	4440
	21st to end	Day	12% 8% 4 8% 6% 6% 5% 4 6% 7% 33%	4791
August	1st to 10th	Day	21% 9% 3 8% 5% 5% 5% 4 6% 8% 28%	4104
	11th to 20th	Day	16% 7% 2 7% 5% 5% 5% 4 6% 9% 34%	3828
	21st to end	Day	16% 7% 2 6% 4 3 4 3 6% 8% 42%	4180
September	1st to 10th	Day	17% 6% 2 6% 5% 4 4 4 5% 7% 39%	2280
	11th to 20th	Day	14% 6% 2 6% 4 4 4 3 5% 7% 46%	2271
	21st to end	Day	19% 7% 3 7% 4 4 4 4 6% 7% 35%	2052
October	1st to 10th	Day	17% 8% 2 6% 4 4 4 4 5% 8% 36%	1900
	11th to 20th	Day	17% 8% 3 7% 5% 4 4 4 5% 7% 37%	1900
	21st to end	Day	22% 10% 3 6% 4 4 5% 3 5% 8% 31%	2014
November	1st to 10th	Day	14% 11% 3 6% 4 4 4 3 4 6% 42%	1680
	11th to 20th	Day	16% 13% 3 8% 4 4 4 3 5% 6% 35%	1691
	21st to end	Day	18% 12% 3 8% 5% 4 4 4 5% 6% 31%	1520
December	1st to 10th	Day	18% 14% 5% 8% 7% 5% 4 4 5% 6% 25%	1520
	11th to 20th	Day	20% 13% 6% 9% 4 4 4 3 5% 5% 28%	1906
	21st to end	Day	22% 17% 5% 10% 6% 5% 4 3 4 4 19%	2772
January	1st to 10th	Night	15% 13% 6% 10% 6% 5% 4 3 5% 6% 29%	4429
	11th to 20th	Night	13% 16% 5% 14% 6% 5% 4 3 4 5% 25%	4426
	21st to end	Night	24% 13% 5% 11% 7% 5% 4 3 4 4 20%	4532
February	1st to 10th	Night	16% 12% 4 9% 6% 4 4 4 4 7% 30%	2470
	11th to 20th	Night	14% 12% 4 10% 6% 4 5% 5% 5% 6% 28%	2313
	21st to end	Night	18% 12% 3 9% 6% 4 4 3 4 5% 32%	1884
March	1st to 10th	Night	22% 15% 4 7% 4 4 3 3 4 5% 29%	3677
	11th to 20th	Night	12% 15% 5% 8% 5% 5% 4 3 4 5% 34%	3479
	21st to end	Night	15% 13% 3 7% 5% 4 4 3 4 5% 38%	3608
April	1st to 10th	Night	17% 13% 4 8% 6% 3 5% 4 4 6% 31%	1900
	11th to 20th	Night	18% 9% 2 6% 5% 4 4 4 5% 6% 38%	1875
	21st to end	Night	19% 8% 3 6% 4 4 4 3 5% 6% 39%	1900
May	1st to 10th	Night	28% 8% 2 6% 4 4 4 3 4 5% 32%	2728
	11th to 20th	Night	22% 10% 2 6% 4 5% 5% 3 5% 7% 31%	2495
	21st to end	Night	14% 8% 3 7% 4 4 4 4 6% 8% 38%	2738
June	1st to 10th	Night	16% 6% 2 5% 4 4 4 4 7% 8% 39%	1520
	11th to 20th	Night	14% 6% 3 7% 4 4 4 4 6% 8% 40%	1520
	21st to end	Night	13% 5% 2 5% 4 4 4 4 6% 9% 44%	1520
July	1st to 10th	Night	12% 6% 3 7% 5% 5% 5% 4 6% 8% 40%	2520
	11th to 20th	Night	12% 5% 3 7% 4 5% 5% 4 7% 10% 38%	2520
	21st to end	Night	16% 7% 2 6% 4 5% 5% 4 5% 6% 40%	2759
August	1st to 10th	Night	21% 8% 3 7% 4 4 4 4 6% 7% 31%	2825
	11th to 20th	Night	18% 6% 3 7% 4 4 4 3 5% 7% 40%	2967
	21st to end	Night	14% 6% 2 6% 4 4 4 3 5% 7% 46%	3476
September	1st to 10th	Night	16% 5% 2 5% 4 4 5% 4 6% 6% 43%	1900
	11th to 20th	Night	13% 6% 2 5% 3 3 4 3 4 6% 50%	1909
	21st to end	Night	19% 7% 2 5% 5% 4 4 3 5% 6% 40%	2123
October	1st to 10th	Night	20% 7% 2 6% 3 4 4 3 5% 7% 40%	2280
	11th to 20th	Night	16% 7% 2 6% 4 4 4 3 5% 4 43%	2280
	21st to end	Night	22% 9% 2 6% 3 4 4 3 6% 7% 34%	2582
November	1st to 10th	Night	13% 10% 3 7% 4 4 4 3 5% 5% 43%	2421
	11th to 20th	Night	18% 11% 2 8% 4 4 3 3 5% 6% 35%	2488
	21st to end	Night	14% 12% 4 6% 5% 4 4 4 6% 7% 34%	2660
December	1st to 10th	Night	20% 12% 5% 8% 5% 5% 4 4 6% 5% 25%	2660
	11th to 20th	Night	18% 14% 4 9% 5% 4 4 4 5% 6% 28%	3288
	21st to end	Night	24% 15% 5% 9% 4 4 4 3 4 5% 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	61% 4 8% 19% 7% 1	3151
	11th to 20th	Day	49% 5% 12% 24% 9% 1	3480
	21st to end	Day	51% 3 8% 17% 19% 2	4023
April	1st to 10th	Day	54% 4 8% 21% 10% 3	2280
	11th to 20th	Day	48% 5% 10% 22% 13% 2	2254
	21st to end	Day	49% 4 9% 22% 13% 4	2280
May	1st to 10th	Day	56% 3 10% 19% 10% 2	4238
	11th to 20th	Day	58% 4 12% 18% 7% 1	4402
	21st to end	Day	39% 5% 12% 26% 15% 1	4837
June	1st to 10th	Day	47% 5% 13% 21% 12% 1	2660
	11th to 20th	Day	47% 5% 13% 22% 10% 1	2660
	21st to end	Day	44% 6% 13% 26% 11%	2660
July	1st to 10th	Day	43% 7% 16% 23% 11%	4370
	11th to 20th	Day	38% 8% 17% 24% 13%	4365
	21st to end	Day	48% 6% 12% 18% 14% 1	4638
August	1st to 10th	Day	54% 6% 14% 19% 7%	4091
	11th to 20th	Day	45% 6% 15% 26% 8%	3867
	21st to end	Day	41% 5% 10% 33% 11% 1	4180
September	1st to 10th	Day	44% 5% 12% 22% 15% 1	2280
	11th to 20th	Day	38% 4 11% 23% 22% 2	2271
	21st to end	Day	47% 5% 10% 22% 15% 2	2052
October	1st to 10th	Day	45% 5% 11% 22% 13% 2	1900
	11th to 20th	Day	46% 5% 11% 25% 13% 2	1900
	21st to end	Day	53% 4 12% 19% 10% 2	2014
November	1st to 10th	Day	43% 4 12% 24% 15% 3	1680
	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	59% 3 9% 19% 10% 1	3687
	11th to 20th	Night	51% 6% 13% 22% 7% 1	3480
	21st to end	Night	49% 4 7% 18% 19% 3	3608
April	1st to 10th	Night	56% 4 9% 19% 12% 2	1900
	11th to 20th	Night	48% 5% 10% 21% 15% 1	1875
	21st to end	Night	47% 5% 10% 21% 15% 3	1900
May	1st to 10th	Night	56% 3 8% 23% 8% 2	2734
	11th to 20th	Night	53% 6% 14% 17% 8% 1	2496
	21st to end	Night	44% 5% 14% 21% 14% 1	2739
June	1st to 10th	Night	42% 5% 11% 27% 15%	1520
	11th to 20th	Night	40% 5% 16% 28% 10% 1	1520
	21st to end	Night	37% 6% 15% 28% 13%	1520
July	1st to 10th	Night	42% 7% 16% 19% 15% 1	2480
	11th to 20th	Night	39% 8% 16% 25% 12% 1	2472
	21st to end	Night	43% 6% 14% 21% 16% 1	2671
August	1st to 10th	Night	51% 6% 15% 20% 7%	2814
	11th to 20th	Night	43% 6% 16% 25% 11%	2994
	21st to end	Night	37% 5% 13% 32% 13% 1	3476
September	1st to 10th	Night	40% 6% 12% 24% 16% 1	1900
	11th to 20th	Night	35% 4 10% 27% 22% 2	1909
	21st to end	Night	44% 4 9% 24% 17% 1	2123
October	1st to 10th	Night	44% 4 12% 24% 14% 1	2280
	11th to 20th	Night	43% 5% 13% 25% 12% 2	2280
	21st to end	Night	48% 5% 13% 21% 12% 1	2582
November	1st to 10th	Night	43% 4 12% 22% 17% 3	2421
	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	33% 23% 30% 12% 2	460
	11th to 20th	Day	32% 25% 25% 13% 4 1	460
	21st to end	Day	35% 23% 25% 10% 4 2	506
April	1st to 10th	Day	34% 23% 26% 12% 5%	460
	11th to 20th	Day	29% 23% 29% 11% 6% 2	452
	21st to end	Day	27% 23% 31% 12% 4 2	460
May	1st to 10th	Day	35% 18% 27% 10% 7% 3	463
	11th to 20th	Day	25% 16% 33% 15% 8% 3	487
	21st to end	Day	18% 12% 31% 24% 12% 3	529
June	1st to 10th	Day	21% 16% 28% 23% 10% 2	490
	11th to 20th	Day	19% 17% 25% 27% 12% 1	490
	21st to end	Day	19% 13% 33% 26% 8% 1	490
July	1st to 10th	Day	15% 8% 29% 28% 16% 5%	485
	11th to 20th	Day	9% 9% 32% 31% 16% 4	484
	21st to end	Day	15% 11% 33% 27% 10% 4	532
August	1st to 10th	Day	14% 9% 27% 26% 18% 6%	486
	11th to 20th	Day	15% 9% 26% 28% 16% 6%	479
	21st to end	Day	13% 11% 28% 25% 14% 8%	539
September	1st to 10th	Day	20% 12% 21% 21% 17% 8%	490
	11th to 20th	Day	14% 8% 25% 23% 18% 11%	490
	21st to end	Day	26% 13% 26% 20% 12% 4	490
October	1st to 10th	Day	26% 14% 24% 19% 13% 5%	490
	11th to 20th	Day	24% 17% 30% 21% 8% 1	490
	21st to end	Day	28% 18% 30% 17% 6% 1	499
November	1st to 10th	Day	24% 21% 22% 23% 9% 1	368
	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% 30% 16% 3	760
	11th to 20th	Night	28% 22% 29% 16% 4	760
	21st to end	Night	25% 22% 31% 16% 6%	836
April	1st to 10th	Night	25% 22% 31% 20% 2	760
	11th to 20th	Night	24% 21% 30% 18% 6%	751
	21st to end	Night	25% 17% 28% 25% 5%	760
May	1st to 10th	Night	28% 12% 27% 23% 9%	516
	11th to 20th	Night	17% 10% 36% 29% 6% 1	374
	21st to end	Night	14% 9% 26% 37% 15%	411
June	1st to 10th	Night	16% 8% 24% 38% 14%	380
	11th to 20th	Night	14% 8% 28% 40% 10%	380
	21st to end	Night	13% 6% 26% 45% 9% 1	380
July	1st to 10th	Night	13% 5% 22% 39% 21% 1	370
	11th to 20th	Night	12% 5% 19% 43% 18% 2	368
	21st to end	Night	14% 7% 19% 42% 17% 1	424
August	1st to 10th	Night	13% 3 20% 43% 18% 2	567
	11th to 20th	Night	16% 3 15% 36% 28% 2	668
	21st to end	Night	15% 5% 18% 36% 24% 1	836
September	1st to 10th	Night	16% 7% 23% 34% 17% 3	760
	11th to 20th	Night	15% 6% 20% 30% 23% 5%	760
	21st to end	Night	22% 9% 21% 29% 17% 2	760
October	1st to 10th	Night	24% 10% 22% 26% 17% 1	760
	11th to 20th	Night	19% 15% 28% 30% 8%	760
	21st to end	Night	27% 14% 30% 22% 6%	836
November	1st to 10th	Night	18% 18% 31% 24% 7% 1	745
	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 2024-10-30 01:22:57. Version ac07

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