Catawissa
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Catawissa clear sky chart from 2005-11-06 to 2025-10-19.

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% 8% 3 6% 4 4 4 4 5% 7% 43%	126564
	Night	14% 8% 3 7% 4 4 4 3 5% 6% 43%	123398
Transparency	Day	39% 4 11% 25% 18% 3	130158
	Night	41% 4 11% 24% 18% 3	127881
Seeing	Day	18% 12% 27% 25% 14% 4	16945
	Night	19% 12% 28% 27% 13% 1	26695

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	13% 12% 7% 13% 5% 4 4 4 5% 5% 29%	3617
	11th to 20th	Day	9% 11% 4 7% 4 5% 3 3 5% 6% 41%	4006
	21st to end	Day	18% 13% 5% 7% 3 3 4 3 4 5% 36%	4488
February	1st to 10th	Day	15% 13% 4 9% 4 4 4 2 5% 5% 35%	1800
	11th to 20th	Day	16% 10% 3 8% 5% 4 4 3 5% 5% 38%	1909
	21st to end	Day	14% 10% 3 8% 4 4 3 4 5% 7% 40%	1650
March	1st to 10th	Day	16% 11% 3 5% 3 2 2 2 4 4 49%	4615
	11th to 20th	Day	10% 7% 1 5% 3 4 3 3 5% 7% 52%	4980
	21st to end	Day	13% 8% 3 7% 5% 5% 5% 4 6% 7% 36%	5725
April	1st to 10th	Day	13% 6% 2 7% 4 4 5% 4 6% 7% 42%	2400
	11th to 20th	Day	18% 9% 3 5% 4 4 4 3 5% 5% 41%	2374
	21st to end	Day	18% 8% 2 7% 5% 5% 4 3 5% 8% 36%	2400
May	1st to 10th	Day	16% 8% 3 7% 5% 5% 5% 4 7% 8% 31%	5451
	11th to 20th	Day	16% 8% 2 6% 4 4 4 4 6% 8% 37%	6309
	21st to end	Day	14% 6% 3 6% 5% 5% 5% 4 6% 7% 40%	6935
June	1st to 10th	Day	10% 5% 2 5% 4 5% 5% 4 6% 9% 46%	2800
	11th to 20th	Day	9% 4 2 5% 4 4 4 4 6% 10% 49%	2800
	21st to end	Day	5% 4 1 4 4 5% 5% 5% 7% 11% 48%	2800
July	1st to 10th	Day	10% 5% 2 6% 4 4 5% 4 5% 9% 46%	6360
	11th to 20th	Day	6% 5% 2 7% 4 5% 6% 5% 8% 12% 41%	6360
	21st to end	Day	7% 5% 2 6% 4 5% 5% 5% 8% 10% 42%	6474
August	1st to 10th	Day	5% 4 2 4 4 4 5% 4 7% 9% 52%	4234
	11th to 20th	Day	13% 5% 2 6% 4 4 5% 4 6% 8% 44%	3858
	21st to end	Day	7% 4 2 4 3 4 4 4 6% 9% 52%	4312
September	1st to 10th	Day	13% 4 2 4 4 3 3 3 6% 7% 51%	2400
	11th to 20th	Day	10% 5% 2 5% 3 3 4 4 5% 8% 51%	2390
	21st to end	Day	8% 5% 2 6% 4 4 4 3 5% 6% 53%	2165
October	1st to 10th	Day	9% 4 2 5% 4 3 3 3 4 6% 56%	2000
	11th to 20th	Day	14% 6% 2 5% 3 3 3 2 4 6% 53%	1980
	21st to end	Day	18% 8% 2 4 3 3 3 3 4 5% 47%	2090
November	1st to 10th	Day	12% 6% 1 4 4 3 2 3 5% 6% 54%	1772
	11th to 20th	Day	14% 7% 3 5% 4 3 3 3 5% 6% 48%	1800
	21st to end	Day	16% 11% 3 6% 3 3 4 3 3 5% 43%	1710
December	1st to 10th	Day	10% 10% 3 6% 3 3 4 3 4 5% 50%	2610
	11th to 20th	Day	12% 10% 5% 8% 4 4 4 3 4 6% 39%	3008
	21st to end	Day	22% 17% 5% 10% 4 4 3 3 3 4 24%	3982
January	1st to 10th	Night	16% 11% 7% 12% 4 4 3 2 4 4 32%	6348
	11th to 20th	Night	11% 10% 4 13% 5% 6% 5% 3 3 4 36%	5970
	21st to end	Night	18% 13% 4 8% 4 4 3 2 3 4 37%	6490
February	1st to 10th	Night	16% 12% 4 8% 4 4 4 3 5% 5% 35%	2600
	11th to 20th	Night	16% 9% 4 8% 4 4 3 2 4 5% 40%	2375
	21st to end	Night	16% 9% 3 8% 5% 3 3 3 4 5% 41%	1980
March	1st to 10th	Night	18% 12% 2 5% 4 3 3 3 3 5% 42%	5281
	11th to 20th	Night	12% 8% 2 5% 4 3 3 3 4 6% 49%	4980
	21st to end	Night	17% 10% 3 7% 5% 5% 5% 4 5% 5% 34%	5202
April	1st to 10th	Night	12% 7% 3 6% 3 3 4 4 5% 6% 46%	2000
	11th to 20th	Night	14% 8% 2 6% 3 4 3 2 5% 7% 45%	1975
	21st to end	Night	19% 8% 2 6% 4 3 3 3 5% 7% 41%	2000
May	1st to 10th	Night	19% 8% 3 7% 4 4 4 4 5% 8% 35%	4429
	11th to 20th	Night	14% 7% 2 6% 4 3 5% 3 6% 8% 42%	3602
	21st to end	Night	14% 8% 2 6% 4 5% 4 4 6% 8% 39%	3942
June	1st to 10th	Night	9% 5% 2 6% 4 4 4 4 7% 9% 48%	1600
	11th to 20th	Night	6% 5% 2 4 4 3 4 3 6% 10% 53%	1600
	21st to end	Night	4 3 2 4 4 4 4 4 5% 10% 56%	1600
July	1st to 10th	Night	10% 6% 2 6% 4 3 4 4 5% 9% 47%	3618
	11th to 20th	Night	5% 5% 2 7% 5% 4 5% 3 6% 10% 49%	3617
	21st to end	Night	6% 5% 2 6% 5% 5% 5% 5% 8% 12% 42%	4393
August	1st to 10th	Night	5% 3 1 4 3 3 4 4 6% 8% 58%	2926
	11th to 20th	Night	10% 5% 2 6% 4 4 4 3 5% 8% 48%	3191
	21st to end	Night	5% 3 1 4 3 4 4 3 5% 10% 58%	3586
September	1st to 10th	Night	12% 5% 2 5% 3 3 3 4 5% 6% 52%	2000
	11th to 20th	Night	8% 5% 2 5% 4 4 4 3 5% 7% 53%	2000
	21st to end	Night	10% 4 2 5% 3 4 4 3 5% 6% 55%	2219
October	1st to 10th	Night	8% 4 2 4 3 3 3 2 4 7% 61%	2400
	11th to 20th	Night	13% 6% 2 5% 2 2 3 3 5% 7% 53%	2377
	21st to end	Night	18% 8% 2 4 3 3 3 2 4 5% 48%	2508
November	1st to 10th	Night	11% 6% 2 4 3 3 3 3 4 5% 56%	2526
	11th to 20th	Night	14% 6% 3 5% 3 3 4 3 5% 6% 48%	2600
	21st to end	Night	18% 9% 3 6% 3 3 2 2 4 5% 44%	2688
December	1st to 10th	Night	12% 9% 3 6% 4 3 3 2 4 5% 47%	4580
	11th to 20th	Night	15% 9% 4 6% 4 4 4 3 4 6% 41%	5199
	21st to end	Night	24% 17% 4 8% 5% 4 4 3 4 4 23%	6996

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	56% 3 11% 19% 10% 2	3618
	11th to 20th	Day	44% 2 10% 23% 17% 4	4006
	21st to end	Day	52% 2 8% 16% 16% 5%	4488
February	1st to 10th	Day	52% 3 10% 23% 11% 1	1800
	11th to 20th	Day	49% 4 9% 19% 14% 4	1919
	21st to end	Day	45% 3 8% 24% 15% 4	1650
March	1st to 10th	Day	41% 2 5% 22% 23% 6%	4615
	11th to 20th	Day	33% 3 8% 25% 25% 6%	4980
	21st to end	Day	46% 4 14% 27% 9% 1	5727
April	1st to 10th	Day	41% 4 11% 25% 18% 1	2400
	11th to 20th	Day	44% 4 9% 24% 16% 4	2374
	21st to end	Day	48% 4 10% 24% 13% 1	2400
May	1st to 10th	Day	49% 5% 12% 21% 12%	5486
	11th to 20th	Day	45% 5% 11% 24% 13% 2	6313
	21st to end	Day	42% 5% 9% 22% 19% 1	6949
June	1st to 10th	Day	35% 5% 12% 28% 17% 2	2800
	11th to 20th	Day	31% 6% 12% 27% 21% 3	2800
	21st to end	Day	28% 8% 17% 26% 16% 5%	2800
July	1st to 10th	Day	34% 5% 10% 30% 18% 2	6291
	11th to 20th	Day	34% 8% 16% 28% 13% 1	6285
	21st to end	Day	34% 8% 17% 30% 11% 1	6290
August	1st to 10th	Day	26% 6% 16% 36% 16%	4220
	11th to 20th	Day	37% 6% 14% 25% 17% 2	3894
	21st to end	Day	27% 6% 15% 34% 15% 3	4311
September	1st to 10th	Day	33% 5% 10% 27% 21% 4	2400
	11th to 20th	Day	32% 4 9% 28% 25% 2	2390
	21st to end	Day	32% 4 7% 29% 26% 3	2165
October	1st to 10th	Day	18% 2 6% 19% 48% 7%	3260
	11th to 20th	Day	24% 2 7% 22% 37% 9%	3220
	21st to end	Day	33% 3 7% 28% 27% 3	3428
November	1st to 10th	Day	33% 3 13% 25% 21% 5%	1772
	11th to 20th	Day	38% 2 8% 24% 22% 5%	1800
	21st to end	Day	45% 3 9% 27% 16%	1710
December	1st to 10th	Day	38% 3 11% 32% 16%	2610
	11th to 20th	Day	47% 3 12% 23% 15% 1	3005
	21st to end	Day	65% 3 11% 13% 7% 1	3982
January	1st to 10th	Night	58% 2 9% 21% 9%	6348
	11th to 20th	Night	54% 2 6% 23% 12% 2	5970
	21st to end	Night	53% 2 8% 19% 16% 2	6490
February	1st to 10th	Night	52% 4 10% 20% 13% 1	2600
	11th to 20th	Night	48% 3 9% 20% 17% 3	2376
	21st to end	Night	47% 3 9% 23% 15% 4	1980
March	1st to 10th	Night	47% 2 6% 22% 20% 3	5281
	11th to 20th	Night	37% 3 10% 23% 21% 7%	4980
	21st to end	Night	51% 4 10% 23% 11% 1	5202
April	1st to 10th	Night	37% 4 11% 26% 18% 4	2000
	11th to 20th	Night	40% 4 9% 25% 18% 4	1975
	21st to end	Night	45% 3 10% 25% 16% 2	2000
May	1st to 10th	Night	49% 6% 13% 19% 13% 1	4459
	11th to 20th	Night	41% 5% 13% 24% 15% 2	3603
	21st to end	Night	42% 6% 12% 23% 15% 2	3950
June	1st to 10th	Night	32% 5% 15% 28% 17% 4	1600
	11th to 20th	Night	27% 5% 12% 28% 25% 4	1600
	21st to end	Night	24% 5% 16% 30% 19% 7%	1600
July	1st to 10th	Night	35% 4 11% 28% 19% 3	3580
	11th to 20th	Night	30% 6% 15% 32% 15% 2	3572
	21st to end	Night	32% 7% 20% 27% 12% 1	4266
August	1st to 10th	Night	22% 7% 18% 32% 20% 1	2916
	11th to 20th	Night	35% 4 14% 27% 18% 3	3221
	21st to end	Night	23% 5% 14% 36% 19% 3	3586
September	1st to 10th	Night	33% 4 10% 25% 23% 6%	2000
	11th to 20th	Night	30% 5% 9% 26% 26% 4	2000
	21st to end	Night	31% 4 8% 25% 27% 4	2219
October	1st to 10th	Night	15% 2 7% 18% 49% 9%	3920
	11th to 20th	Night	22% 2 7% 24% 35% 10%	3876
	21st to end	Night	31% 3 8% 26% 27% 5%	4120
November	1st to 10th	Night	31% 3 12% 26% 22% 6%	2526
	11th to 20th	Night	38% 3 7% 24% 23% 5%	2600
	21st to end	Night	43% 3 9% 25% 18% 2	2688
December	1st to 10th	Night	40% 3 10% 32% 14% 1	4580
	11th to 20th	Night	45% 3 12% 22% 18% 1	5201
	21st to end	Night	66% 3 12% 13% 5% 1	6996

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	28% 23% 31% 14% 3 1	300
	11th to 20th	Day	33% 24% 33% 10%	300
	21st to end	Day	24% 27% 37% 11% 2	330
February	1st to 10th	Day	29% 22% 36% 10% 2	300
	11th to 20th	Day	34% 25% 27% 11% 3	300
	21st to end	Day	32% 24% 35% 8% 1	249
March	1st to 10th	Day	25% 21% 42% 10% 2	300
	11th to 20th	Day	36% 19% 31% 10% 3 1	300
	21st to end	Day	35% 18% 32% 12% 3	438
April	1st to 10th	Day	27% 17% 32% 18% 5%	500
	11th to 20th	Day	30% 16% 30% 17% 6% 1	492
	21st to end	Day	25% 17% 35% 18% 5%	500
May	1st to 10th	Day	22% 18% 33% 20% 6% 1	503
	11th to 20th	Day	21% 15% 29% 23% 12% 2	715
	21st to end	Day	14% 12% 33% 25% 11% 5%	789
June	1st to 10th	Day	12% 7% 25% 32% 19% 5%	730
	11th to 20th	Day	10% 6% 23% 41% 16% 5%	730
	21st to end	Day	5% 8% 31% 35% 16% 5%	730
July	1st to 10th	Day	12% 3 17% 31% 27% 11%	721
	11th to 20th	Day	6% 4 26% 38% 21% 5%	718
	21st to end	Day	9% 4 19% 32% 29% 7%	794
August	1st to 10th	Day	8% 3 19% 40% 25% 6%	726
	11th to 20th	Day	13% 3 20% 30% 27% 7%	528
	21st to end	Day	10% 2 17% 30% 31% 9%	583
September	1st to 10th	Day	13% 4 18% 32% 27% 7%	530
	11th to 20th	Day	10% 2 18% 30% 26% 12%	530
	21st to end	Day	12% 9% 21% 31% 20% 7%	495
October	1st to 10th	Day	13% 9% 27% 35% 11% 5%	330
	11th to 20th	Day	22% 15% 32% 22% 8% 2	324
	21st to end	Day	34% 18% 29% 17% 2	330
November	1st to 10th	Day	17% 12% 43% 17% 7% 3	300
	11th to 20th	Day	26% 18% 30% 17% 7% 1	300
	21st to end	Day	31% 14% 32% 17% 5% 1	300
December	1st to 10th	Day	23% 22% 32% 16% 6% 2	300
	11th to 20th	Day	25% 20% 35% 16% 4	300
	21st to end	Day	32% 22% 33% 11% 2	330
January	1st to 10th	Night	22% 21% 34% 20% 4	1000
	11th to 20th	Night	24% 22% 34% 17% 3	1000
	21st to end	Night	23% 19% 36% 20% 2	1100
February	1st to 10th	Night	25% 19% 33% 20% 3	1000
	11th to 20th	Night	25% 19% 38% 15% 2	820
	21st to end	Night	24% 20% 35% 19% 2	660
March	1st to 10th	Night	26% 17% 35% 19% 3	760
	11th to 20th	Night	26% 13% 34% 23% 5%	600
	21st to end	Night	27% 15% 34% 21% 4	660
April	1st to 10th	Night	18% 18% 36% 24% 5%	600
	11th to 20th	Night	20% 14% 33% 24% 7%	593
	21st to end	Night	23% 13% 35% 24% 5%	600
May	1st to 10th	Night	19% 11% 32% 31% 8% 1	600
	11th to 20th	Night	19% 6% 28% 32% 14% 1	591
	21st to end	Night	12% 6% 26% 34% 18% 2	650
June	1st to 10th	Night	11% 4 20% 38% 25% 1	600
	11th to 20th	Night	9% 2 25% 44% 19% 1	600
	21st to end	Night	5% 4 25% 44% 21% 2	600
July	1st to 10th	Night	11% 1 12% 37% 33% 5%	585
	11th to 20th	Night	5% 2 16% 43% 31% 2	582
	21st to end	Night	7% 2 15% 41% 33% 3	657
August	1st to 10th	Night	7% 2 13% 43% 33% 3	597
	11th to 20th	Night	8% 3 13% 41% 31% 4	594
	21st to end	Night	7% 1 14% 37% 36% 4	660
September	1st to 10th	Night	14% 3 15% 34% 29% 5%	600
	11th to 20th	Night	11% 3 14% 35% 31% 6%	600
	21st to end	Night	11% 7% 22% 30% 25% 4	789
October	1st to 10th	Night	9% 6% 26% 33% 22% 4	800
	11th to 20th	Night	17% 13% 30% 26% 13% 1	793
	21st to end	Night	25% 14% 32% 23% 6%	836
November	1st to 10th	Night	14% 12% 37% 26% 10%	780
	11th to 20th	Night	21% 15% 33% 25% 7%	800
	21st to end	Night	25% 16% 32% 22% 5%	888
December	1st to 10th	Night	25% 14% 33% 23% 4 1	1000
	11th to 20th	Night	26% 14% 31% 26% 4	1000
	21st to end	Night	30% 17% 31% 19% 2	1100

Page generated at 2025-10-16 00:50:25. Version ac07

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