Pine Islands
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pine Islands clear sky chart from 2005-11-06 to 2024-04-10.

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% 11% 4 7% 6% 3 4 4 5% 6% 33%	83132
	Night	18% 13% 5% 9% 6% 3 4 4 4 6% 26%	85647
Transparency	Day	36% 36% 9% 12% 6% 1	82836
	Night	42% 35% 8% 10% 5%	85479
Seeing	Day	21% 12% 28% 24% 11% 3	14169
	Night	24% 11% 28% 25% 11% 1	23442

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	17% 20% 14% 10% 5% 3 5% 4 3 4 14%	2208
	11th to 20th	Day	12% 17% 9% 19% 12% 3 5% 5% 4 4 10%	2649
	21st to end	Day	17% 22% 7% 11% 7% 3 4 4 4 4 16%	3124
February	1st to 10th	Day	14% 18% 7% 15% 8% 4 4 4 3 4 19%	1710
	11th to 20th	Day	13% 14% 6% 10% 8% 4 4 4 5% 6% 27%	1663
	21st to end	Day	16% 16% 7% 8% 6% 4 5% 4 4 5% 25%	1462
March	1st to 10th	Day	19% 11% 4 6% 6% 3 4 4 4 5% 32%	3398
	11th to 20th	Day	12% 14% 6% 8% 7% 4 6% 4 5% 6% 29%	3480
	21st to end	Day	14% 8% 3 5% 6% 3 5% 5% 6% 7% 37%	3815
April	1st to 10th	Day	20% 10% 3 7% 6% 4 4 4 5% 5% 33%	2218
	11th to 20th	Day	21% 7% 4 5% 4 2 4 4 5% 6% 38%	2262
	21st to end	Day	21% 7% 3 6% 6% 3 4 4 5% 7% 36%	2340
May	1st to 10th	Day	18% 6% 3 5% 5% 3 4 5% 6% 7% 38%	2340
	11th to 20th	Day	14% 7% 3 5% 5% 3 4 4 5% 7% 44%	2478
	21st to end	Day	12% 5% 3 5% 5% 3 5% 5% 6% 8% 44%	2725
June	1st to 10th	Day	16% 6% 2 4 5% 3 5% 4 6% 8% 40%	2574
	11th to 20th	Day	13% 5% 2 4 5% 3 5% 4 6% 9% 43%	2700
	21st to end	Day	15% 7% 3 4 4 3 4 5% 6% 8% 40%	2700
July	1st to 10th	Day	10% 4 2 4 4 3 4 5% 6% 9% 49%	2700
	11th to 20th	Day	11% 6% 2 5% 5% 2 4 4 6% 9% 47%	2620
	21st to end	Day	11% 5% 2 5% 5% 3 4 4 6% 8% 46%	2600
August	1st to 10th	Day	12% 5% 2 5% 5% 3 3 4 6% 9% 47%	2327
	11th to 20th	Day	12% 4 2 4 5% 3 4 5% 6% 10% 46%	2303
	21st to end	Day	12% 5% 2 6% 6% 3 5% 4 6% 8% 42%	2520
September	1st to 10th	Day	13% 6% 2 5% 6% 3 4 4 5% 8% 44%	2160
	11th to 20th	Day	14% 5% 2 5% 5% 3 4 5% 5% 7% 44%	2027
	21st to end	Day	18% 7% 3 5% 7% 3 5% 4 5% 6% 37%	1962
October	1st to 10th	Day	23% 8% 2 5% 5% 3 4 4 4 6% 35%	1800
	11th to 20th	Day	28% 10% 4 7% 6% 3 5% 5% 3 6% 22%	1800
	21st to end	Day	32% 12% 4 8% 5% 3 4 4 4 5% 19%	1958
November	1st to 10th	Day	21% 15% 5% 7% 7% 3 4 3 5% 7% 23%	1554
	11th to 20th	Day	22% 15% 6% 9% 7% 4 5% 4 4 6% 17%	1520
	21st to end	Day	25% 19% 5% 8% 9% 4 5% 5% 4 4 10%	1520
December	1st to 10th	Day	19% 27% 8% 9% 7% 4 5% 4 3 4 10%	1520
	11th to 20th	Day	21% 23% 7% 11% 7% 3 5% 4 3 4 13%	1906
	21st to end	Day	27% 17% 6% 11% 7% 4 5% 4 3 5% 11%	2489
January	1st to 10th	Night	17% 24% 12% 14% 7% 4 4 3 3 3 10%	4748
	11th to 20th	Night	15% 17% 8% 21% 9% 4 4 4 4 4 11%	4305
	21st to end	Night	18% 18% 8% 12% 8% 4 5% 4 5% 5% 15%	4532
February	1st to 10th	Night	14% 19% 7% 12% 8% 4 6% 3 5% 5% 17%	2470
	11th to 20th	Night	14% 14% 8% 12% 8% 3 5% 4 4 5% 23%	2403
	21st to end	Night	18% 13% 6% 9% 6% 4 5% 4 5% 5% 25%	1989
March	1st to 10th	Night	16% 12% 4 7% 6% 3 5% 4 5% 7% 32%	3441
	11th to 20th	Night	12% 15% 5% 8% 6% 3 4 4 4 6% 32%	3479
	21st to end	Night	15% 10% 4 7% 7% 5% 6% 5% 5% 5% 32%	3817
April	1st to 10th	Night	22% 11% 4 6% 6% 3 5% 4 5% 4 31%	1951
	11th to 20th	Night	19% 9% 4 6% 5% 3 3 4 5% 6% 37%	1661
	21st to end	Night	20% 8% 4 7% 7% 4 4 4 4 6% 32%	1620
May	1st to 10th	Night	17% 6% 3 5% 6% 4 4 5% 5% 8% 38%	1620
	11th to 20th	Night	16% 6% 3 5% 5% 3 4 3 4 7% 43%	1415
	21st to end	Night	10% 5% 2 5% 5% 3 5% 5% 5% 8% 46%	1550
June	1st to 10th	Night	15% 7% 3 4 7% 3 5% 5% 6% 6% 39%	1382
	11th to 20th	Night	12% 5% 3 4 4 4 4 5% 6% 9% 44%	1260
	21st to end	Night	14% 7% 2 5% 4 4 5% 4 7% 7% 42%	1260
July	1st to 10th	Night	9% 4 2 4 4 2 4 4 5% 8% 54%	1260
	11th to 20th	Night	11% 6% 3 6% 5% 3 6% 4 5% 8% 45%	1336
	21st to end	Night	10% 5% 2 5% 5% 3 4 5% 5% 7% 47%	1716
August	1st to 10th	Night	10% 5% 2 5% 4 3 5% 4 6% 8% 47%	1611
	11th to 20th	Night	10% 5% 3 5% 5% 3 5% 5% 6% 8% 45%	1598
	21st to end	Night	16% 6% 2 5% 6% 3 5% 5% 5% 7% 42%	1818
September	1st to 10th	Night	12% 4 2 5% 5% 3 5% 5% 5% 8% 46%	1800
	11th to 20th	Night	14% 5% 3 5% 6% 2 5% 4 6% 7% 43%	1930
	21st to end	Night	19% 6% 3 5% 6% 3 4 4 5% 7% 37%	1998
October	1st to 10th	Night	21% 9% 3 7% 6% 3 4 4 4 6% 33%	2160
	11th to 20th	Night	30% 11% 4 7% 6% 3 4 4 5% 6% 21%	2160
	21st to end	Night	30% 13% 5% 8% 6% 2 4 4 5% 5% 18%	2394
November	1st to 10th	Night	23% 15% 4 7% 5% 2 4 3 5% 6% 26%	2523
	11th to 20th	Night	20% 20% 5% 8% 6% 4 5% 4 5% 5% 19%	2660
	21st to end	Night	26% 21% 6% 9% 7% 3 3 4 4 4 12%	2660
December	1st to 10th	Night	22% 27% 8% 11% 6% 3 4 3 3 3 8%	2660
	11th to 20th	Night	20% 23% 8% 11% 7% 3 4 4 3 5% 13%	3288
	21st to end	Night	26% 20% 7% 13% 8% 3 4 3 3 4 8%	5172

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	54% 31% 9% 5%	2209
	11th to 20th	Day	62% 30% 4 3 1	2649
	21st to end	Day	59% 26% 8% 5% 1	3124
February	1st to 10th	Day	46% 37% 6% 10% 1	1710
	11th to 20th	Day	41% 40% 9% 6% 4	1672
	21st to end	Day	42% 36% 9% 9% 4	1462
March	1st to 10th	Day	43% 26% 13% 10% 7%	3401
	11th to 20th	Day	43% 28% 12% 13% 3 1	3480
	21st to end	Day	32% 28% 16% 16% 7% 1	3815
April	1st to 10th	Day	35% 36% 9% 12% 7% 1	2218
	11th to 20th	Day	30% 37% 7% 16% 9%	2262
	21st to end	Day	33% 38% 6% 13% 8% 2	2340
May	1st to 10th	Day	28% 37% 9% 15% 10% 2	2340
	11th to 20th	Day	27% 39% 7% 16% 10% 1	2482
	21st to end	Day	23% 39% 11% 14% 10% 3	2725
June	1st to 10th	Day	29% 39% 8% 16% 8%	2574
	11th to 20th	Day	22% 39% 10% 17% 12%	2700
	21st to end	Day	27% 41% 10% 14% 7%	2700
July	1st to 10th	Day	20% 42% 11% 18% 8% 1	2626
	11th to 20th	Day	22% 40% 11% 18% 8% 1	2539
	21st to end	Day	24% 42% 10% 16% 8%	2455
August	1st to 10th	Day	26% 40% 11% 16% 7% 1	2314
	11th to 20th	Day	20% 39% 13% 19% 9%	2303
	21st to end	Day	26% 40% 10% 14% 8% 1	2520
September	1st to 10th	Day	25% 38% 10% 19% 7% 1	2160
	11th to 20th	Day	27% 41% 11% 16% 6%	2027
	21st to end	Day	33% 40% 7% 15% 5%	1962
October	1st to 10th	Day	34% 40% 8% 12% 6% 1	1800
	11th to 20th	Day	43% 38% 8% 7% 3	1800
	21st to end	Day	44% 39% 7% 6% 3	1958
November	1st to 10th	Day	34% 43% 9% 11% 3	1554
	11th to 20th	Day	40% 44% 9% 4 4	1520
	21st to end	Day	48% 42% 7% 3 1	1520
December	1st to 10th	Day	52% 40% 5% 2 1	1520
	11th to 20th	Day	51% 35% 8% 6% 1	1906
	21st to end	Day	60% 28% 6% 4 1	2489
January	1st to 10th	Night	62% 28% 6% 4 1	4748
	11th to 20th	Night	60% 29% 7% 3 1	4305
	21st to end	Night	58% 28% 10% 4 1	4532
February	1st to 10th	Night	45% 37% 7% 10% 1	2470
	11th to 20th	Night	46% 38% 8% 7% 2	2405
	21st to end	Night	41% 35% 10% 10% 3	1989
March	1st to 10th	Night	40% 26% 12% 14% 6%	3451
	11th to 20th	Night	41% 27% 14% 13% 5% 1	3480
	21st to end	Night	36% 30% 12% 15% 6% 1	3817
April	1st to 10th	Night	36% 36% 6% 14% 7% 1	1951
	11th to 20th	Night	32% 37% 6% 14% 9% 1	1661
	21st to end	Night	35% 38% 5% 9% 11% 1	1620
May	1st to 10th	Night	29% 37% 8% 13% 12% 2	1620
	11th to 20th	Night	26% 37% 7% 17% 12% 2	1416
	21st to end	Night	22% 40% 11% 14% 12% 3	1551
June	1st to 10th	Night	32% 40% 8% 12% 9%	1382
	11th to 20th	Night	24% 38% 11% 15% 12%	1260
	21st to end	Night	29% 40% 9% 16% 6%	1260
July	1st to 10th	Night	19% 40% 10% 18% 12% 1	1225
	11th to 20th	Night	25% 40% 10% 16% 8% 1	1294
	21st to end	Night	22% 41% 10% 18% 9% 1	1621
August	1st to 10th	Night	26% 38% 11% 18% 7%	1600
	11th to 20th	Night	21% 39% 13% 17% 11% 1	1598
	21st to end	Night	27% 38% 9% 16% 9% 1	1818
September	1st to 10th	Night	25% 39% 10% 17% 8% 1	1800
	11th to 20th	Night	26% 40% 11% 18% 5%	1930
	21st to end	Night	31% 39% 9% 16% 5%	1998
October	1st to 10th	Night	33% 39% 8% 12% 7%	2160
	11th to 20th	Night	43% 39% 8% 8% 3	2160
	21st to end	Night	46% 39% 6% 7% 3	2394
November	1st to 10th	Night	32% 44% 8% 12% 4	2523
	11th to 20th	Night	41% 43% 7% 6% 2 1	2660
	21st to end	Night	48% 40% 7% 5%	2660
December	1st to 10th	Night	52% 41% 4 2	2660
	11th to 20th	Night	51% 36% 7% 4 1	3288
	21st to end	Night	65% 27% 4 4	5172

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	19% 25% 34% 13% 8% 1	180
	11th to 20th	Day	23% 22% 32% 16% 6% 1	234
	21st to end	Day	30% 12% 30% 21% 6%	297
February	1st to 10th	Day	30% 20% 33% 13% 3 1	270
	11th to 20th	Day	20% 23% 40% 15% 1	270
	21st to end	Day	34% 22% 33% 11%	225
March	1st to 10th	Day	22% 17% 36% 21% 4	437
	11th to 20th	Day	22% 17% 34% 22% 5% 1	460
	21st to end	Day	26% 15% 30% 22% 6% 1	506
April	1st to 10th	Day	24% 16% 30% 22% 8%	457
	11th to 20th	Day	29% 14% 27% 18% 9% 3	412
	21st to end	Day	26% 16% 31% 19% 8% 1	420
May	1st to 10th	Day	21% 9% 35% 23% 9% 3	423
	11th to 20th	Day	19% 9% 29% 26% 13% 3	447
	21st to end	Day	15% 8% 29% 29% 15% 4	485
June	1st to 10th	Day	18% 9% 28% 30% 14% 1	504
	11th to 20th	Day	16% 8% 28% 32% 13% 4	630
	21st to end	Day	18% 5% 27% 32% 15% 2	630
July	1st to 10th	Day	10% 6% 26% 32% 22% 3	621
	11th to 20th	Day	15% 7% 22% 33% 18% 5%	538
	21st to end	Day	13% 6% 27% 35% 16% 3	488
August	1st to 10th	Day	15% 5% 20% 33% 20% 8%	446
	11th to 20th	Day	14% 3 19% 34% 20% 9%	439
	21st to end	Day	17% 8% 24% 29% 16% 7%	495
September	1st to 10th	Day	13% 8% 25% 28% 19% 7%	450
	11th to 20th	Day	14% 7% 25% 28% 20% 7%	450
	21st to end	Day	21% 8% 24% 26% 19% 2	450
October	1st to 10th	Day	27% 12% 26% 17% 15% 4	450
	11th to 20th	Day	27% 19% 30% 18% 5% 1	450
	21st to end	Day	36% 16% 30% 14% 4	473
November	1st to 10th	Day	28% 20% 29% 19% 4	214
	11th to 20th	Day	24% 23% 35% 16% 2	180
	21st to end	Day	31% 19% 37% 14%	180
December	1st to 10th	Day	32% 21% 30% 13% 3 1	180
	11th to 20th	Day	35% 24% 27% 11% 2 1	180
	21st to end	Day	33% 22% 31% 12% 2	198
January	1st to 10th	Night	28% 18% 30% 18% 5% 1	950
	11th to 20th	Night	31% 15% 31% 19% 5% 1	795
	21st to end	Night	22% 10% 32% 26% 9% 1	836
February	1st to 10th	Night	24% 18% 32% 22% 4	760
	11th to 20th	Night	22% 13% 34% 24% 6%	743
	21st to end	Night	25% 17% 31% 21% 6%	628
March	1st to 10th	Night	21% 14% 36% 25% 5%	760
	11th to 20th	Night	18% 16% 34% 25% 6% 1	760
	21st to end	Night	21% 9% 33% 27% 10%	836
April	1st to 10th	Night	28% 11% 30% 26% 5%	760
	11th to 20th	Night	23% 11% 27% 27% 12% 1	597
	21st to end	Night	23% 9% 27% 27% 13%	540
May	1st to 10th	Night	21% 6% 21% 37% 14% 2	540
	11th to 20th	Night	18% 6% 25% 38% 13% 1	354
	21st to end	Night	12% 4 26% 38% 19% 1	389
June	1st to 10th	Night	17% 5% 25% 38% 14% 1	360
	11th to 20th	Night	15% 6% 19% 42% 16% 1	360
	21st to end	Night	18% 5% 22% 32% 23% 1	360
July	1st to 10th	Night	10% 5% 18% 40% 25% 3	350
	11th to 20th	Night	13% 4 23% 31% 26% 2	348
	21st to end	Night	12% 4 24% 36% 23% 2	536
August	1st to 10th	Night	12% 4 17% 36% 28% 3	537
	11th to 20th	Night	12% 3 18% 36% 26% 5%	534
	21st to end	Night	17% 5% 23% 27% 24% 4	630
September	1st to 10th	Night	14% 6% 23% 31% 21% 6%	720
	11th to 20th	Night	15% 7% 22% 30% 20% 6%	720
	21st to end	Night	20% 9% 19% 29% 18% 4	720
October	1st to 10th	Night	24% 12% 26% 23% 15% 1	720
	11th to 20th	Night	34% 13% 24% 21% 7% 1	720
	21st to end	Night	34% 15% 28% 19% 3	792
November	1st to 10th	Night	32% 12% 26% 19% 10%	740
	11th to 20th	Night	29% 19% 31% 16% 5%	760
	21st to end	Night	37% 14% 31% 15% 3	760
December	1st to 10th	Night	36% 20% 28% 13% 3	760
	11th to 20th	Night	29% 20% 34% 13% 4	760
	21st to end	Night	33% 14% 31% 19% 2	1007

Page generated at 2024-04-07 09:28:16. Version ac07

Copyright © 2024 Attilla Danko.