Baltic Corners
Clear Sky Chart
History

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

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 8% 5% 4 4 4 5% 7% 32%	101549
	Night	18% 11% 4 8% 5% 4 4 3 5% 6% 31%	97468
Transparency	Day	50% 7% 13% 20% 9% 1	105008
	Night	52% 6% 12% 19% 9% 1	102098
Seeing	Day	22% 16% 29% 21% 9% 2	14531
	Night	23% 12% 30% 25% 9% 1	23542

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% 18% 5% 13% 5% 4 4 3 4 4 23%	2517
	11th to 20th	Day	13% 14% 7% 12% 7% 5% 5% 4 5% 5% 23%	2520
	21st to end	Day	15% 19% 6% 11% 6% 6% 5% 4 5% 5% 18%	2804
February	1st to 10th	Day	15% 17% 5% 11% 5% 3 4 3 5% 6% 25%	1710
	11th to 20th	Day	14% 15% 5% 11% 6% 5% 3 4 4 5% 27%	1715
	21st to end	Day	20% 15% 5% 8% 5% 5% 4 3 5% 5% 26%	1570
March	1st to 10th	Day	20% 13% 4 9% 6% 5% 4 3 4 5% 27%	3116
	11th to 20th	Day	14% 18% 5% 10% 5% 5% 4 3 4 5% 26%	3379
	21st to end	Day	16% 8% 3 8% 5% 4 4 3 4 6% 39%	4094
April	1st to 10th	Day	23% 13% 3 6% 4 4 4 3 3 5% 33%	2280
	11th to 20th	Day	21% 10% 3 7% 5% 3 3 2 4 6% 35%	2254
	21st to end	Day	23% 10% 3 8% 4 4 4 3 4 5% 31%	2399
May	1st to 10th	Day	21% 9% 3 8% 4 4 5% 4 6% 7% 29%	4426
	11th to 20th	Day	19% 9% 3 9% 5% 4 4 4 5% 7% 32%	4398
	21st to end	Day	16% 6% 3 7% 4 4 5% 4 6% 8% 36%	4837
June	1st to 10th	Day	23% 9% 3 7% 5% 4 4 4 5% 7% 29%	2660
	11th to 20th	Day	15% 7% 2 6% 5% 6% 5% 4 6% 8% 36%	2660
	21st to end	Day	21% 7% 3 6% 4 5% 5% 4 6% 9% 30%	2660
July	1st to 10th	Day	12% 7% 3 8% 6% 5% 5% 4 7% 9% 34%	4440
	11th to 20th	Day	14% 6% 2 6% 4 5% 5% 5% 7% 9% 37%	4440
	21st to end	Day	12% 6% 2 5% 4 5% 4 4 7% 9% 43%	4814
August	1st to 10th	Day	15% 7% 3 8% 5% 4 5% 4 6% 9% 34%	4423
	11th to 20th	Day	15% 7% 2 6% 4 4 4 4 6% 8% 39%	3953
	21st to end	Day	15% 5% 2 6% 4 5% 5% 4 6% 8% 39%	4180
September	1st to 10th	Day	14% 7% 2 5% 4 4 5% 4 5% 8% 43%	2280
	11th to 20th	Day	14% 5% 2 5% 3 4 4 3 5% 7% 48%	2242
	21st to end	Day	19% 6% 2 5% 4 4 3 3 6% 7% 41%	2089
October	1st to 10th	Day	21% 7% 2 6% 4 4 5% 4 5% 7% 36%	1900
	11th to 20th	Day	21% 10% 4 9% 5% 4 3 4 4 6% 30%	1900
	21st to end	Day	25% 11% 3 7% 4 4 5% 3 5% 5% 28%	1891
November	1st to 10th	Day	16% 9% 4 8% 4 4 4 5% 6% 6% 33%	1698
	11th to 20th	Day	18% 14% 3 8% 6% 3 4 4 5% 7% 28%	1582
	21st to end	Day	22% 14% 4 10% 5% 5% 5% 3 5% 6% 22%	1520
December	1st to 10th	Day	24% 16% 6% 9% 5% 5% 5% 4 4 4 17%	1520
	11th to 20th	Day	22% 15% 5% 10% 4 5% 4 3 4 6% 22%	1906
	21st to end	Day	27% 19% 5% 10% 5% 4 3 2 3 2 20%	2772
January	1st to 10th	Night	17% 17% 6% 12% 6% 4 4 3 4 5% 21%	4429
	11th to 20th	Night	13% 15% 6% 14% 7% 6% 5% 4 5% 6% 19%	4440
	21st to end	Night	17% 19% 6% 11% 6% 5% 3 2 4 5% 21%	4848
February	1st to 10th	Night	15% 14% 5% 12% 7% 6% 4 4 5% 5% 22%	2470
	11th to 20th	Night	14% 13% 4 11% 7% 5% 4 4 5% 5% 28%	2350
	21st to end	Night	16% 15% 5% 10% 6% 4 4 4 4 5% 29%	1884
March	1st to 10th	Night	20% 12% 4 8% 4 4 4 3 4 4 32%	3724
	11th to 20th	Night	18% 16% 5% 9% 6% 4 4 3 4 6% 26%	3575
	21st to end	Night	14% 11% 4 8% 4 4 4 3 4 5% 38%	3537
April	1st to 10th	Night	23% 11% 3 7% 4 5% 3 3 4 6% 31%	1900
	11th to 20th	Night	21% 10% 3 7% 5% 4 4 3 4 6% 35%	1875
	21st to end	Night	22% 9% 3 7% 4 4 3 3 4 6% 34%	1796
May	1st to 10th	Night	20% 9% 3 8% 5% 4 5% 4 6% 7% 29%	2514
	11th to 20th	Night	21% 9% 3 6% 4 3 4 4 5% 6% 36%	2495
	21st to end	Night	14% 8% 2 6% 5% 4 5% 4 6% 8% 38%	2738
June	1st to 10th	Night	18% 8% 2 5% 6% 5% 6% 5% 6% 9% 29%	1520
	11th to 20th	Night	16% 7% 2 6% 4 4 5% 4 6% 7% 40%	1520
	21st to end	Night	19% 7% 3 6% 4 4 4 4 6% 7% 34%	1520
July	1st to 10th	Night	14% 7% 3 8% 6% 5% 5% 5% 6% 8% 35%	2520
	11th to 20th	Night	13% 6% 2 7% 4 4 4 4 6% 7% 42%	2520
	21st to end	Night	13% 6% 2 6% 4 4 4 4 6% 8% 43%	2739
August	1st to 10th	Night	14% 8% 3 7% 4 4 4 4 6% 8% 39%	2506
	11th to 20th	Night	15% 7% 2 6% 4 4 4 3 6% 8% 40%	2840
	21st to end	Night	13% 6% 2 7% 4 4 5% 3 5% 8% 41%	3476
September	1st to 10th	Night	11% 6% 2 8% 5% 4 5% 4 6% 6% 44%	1900
	11th to 20th	Night	14% 6% 1 5% 4 2 3 3 4 7% 50%	1938
	21st to end	Night	17% 5% 2 6% 3 5% 5% 3 5% 6% 43%	2090
October	1st to 10th	Night	20% 7% 3 6% 4 4 4 3 4 6% 38%	2279
	11th to 20th	Night	20% 9% 3 7% 5% 4 5% 3 4 6% 33%	2280
	21st to end	Night	23% 10% 3 9% 4 4 4 3 5% 5% 29%	2707
November	1st to 10th	Night	20% 10% 3 8% 4 3 4 3 5% 6% 34%	2453
	11th to 20th	Night	19% 11% 4 9% 5% 4 5% 4 4 5% 31%	2593
	21st to end	Night	22% 13% 4 10% 5% 4 4 3 4 6% 23%	2660
December	1st to 10th	Night	20% 17% 6% 9% 7% 5% 5% 4 5% 5% 18%	2660
	11th to 20th	Night	23% 15% 4 9% 5% 4 4 3 4 3 25%	3288
	21st to end	Night	30% 19% 4 10% 4 3 3 3 3 3 19%	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	64% 7% 13% 10% 5% 1	2518
	11th to 20th	Day	61% 7% 13% 12% 7% 1	2520
	21st to end	Day	66% 8% 13% 9% 5%	2804
February	1st to 10th	Day	62% 5% 9% 19% 4 2	1710
	11th to 20th	Day	58% 6% 12% 16% 7% 1	1724
	21st to end	Day	61% 4 12% 13% 9% 1	1570
March	1st to 10th	Day	59% 6% 10% 18% 7% 1	3119
	11th to 20th	Day	58% 7% 11% 14% 9% 1	3379
	21st to end	Day	45% 6% 9% 19% 18% 2	4094
April	1st to 10th	Day	54% 5% 8% 19% 11% 3	2280
	11th to 20th	Day	51% 5% 7% 20% 15% 2	2254
	21st to end	Day	54% 6% 8% 15% 12% 4	2399
May	1st to 10th	Day	51% 9% 10% 19% 9% 1	4440
	11th to 20th	Day	50% 7% 14% 18% 9% 1	4402
	21st to end	Day	42% 8% 14% 22% 13% 1	4837
June	1st to 10th	Day	53% 6% 11% 18% 11% 1	2660
	11th to 20th	Day	43% 7% 13% 22% 12% 2	2660
	21st to end	Day	49% 9% 13% 19% 9% 1	2660
July	1st to 10th	Day	43% 8% 14% 24% 11%	4370
	11th to 20th	Day	40% 8% 15% 29% 7%	4365
	21st to end	Day	36% 8% 15% 32% 9%	4661
August	1st to 10th	Day	45% 7% 17% 22% 8%	4409
	11th to 20th	Day	41% 8% 17% 28% 6%	3993
	21st to end	Day	41% 7% 18% 22% 11% 1	4180
September	1st to 10th	Day	38% 8% 15% 27% 12%	2280
	11th to 20th	Day	35% 6% 14% 31% 14% 1	2242
	21st to end	Day	42% 8% 14% 26% 10%	2089
October	1st to 10th	Day	45% 6% 12% 29% 8%	3160
	11th to 20th	Day	47% 5% 16% 25% 7%	3140
	21st to end	Day	47% 6% 18% 22% 6%	3091
November	1st to 10th	Day	50% 8% 14% 21% 7% 1	1698
	11th to 20th	Day	55% 6% 13% 15% 9%	1582
	21st to end	Day	63% 6% 15% 11% 5%	1520
December	1st to 10th	Day	69% 7% 11% 10% 3	1520
	11th to 20th	Day	64% 8% 12% 13% 4	1906
	21st to end	Day	70% 5% 8% 13% 4	2772
January	1st to 10th	Night	65% 6% 15% 10% 3	4429
	11th to 20th	Night	63% 9% 14% 9% 4	4440
	21st to end	Night	66% 6% 12% 10% 6% 1	4848
February	1st to 10th	Night	63% 6% 10% 15% 6% 1	2470
	11th to 20th	Night	57% 6% 11% 18% 7%	2352
	21st to end	Night	57% 4 9% 18% 11% 1	1884
March	1st to 10th	Night	54% 5% 10% 18% 9% 3	3734
	11th to 20th	Night	58% 7% 11% 14% 7% 2	3576
	21st to end	Night	47% 5% 6% 23% 16% 3	3537
April	1st to 10th	Night	54% 5% 8% 18% 12% 2	1900
	11th to 20th	Night	50% 7% 8% 19% 14% 1	1875
	21st to end	Night	51% 5% 9% 17% 15% 4	1796
May	1st to 10th	Night	50% 9% 12% 17% 9% 3	2520
	11th to 20th	Night	46% 9% 11% 18% 13% 2	2496
	21st to end	Night	41% 9% 12% 19% 17% 2	2739
June	1st to 10th	Night	48% 8% 14% 18% 11% 1	1520
	11th to 20th	Night	42% 7% 12% 21% 16% 2	1520
	21st to end	Night	47% 8% 14% 18% 13% 1	1520
July	1st to 10th	Night	45% 8% 13% 19% 13% 1	2480
	11th to 20th	Night	38% 8% 15% 31% 8%	2472
	21st to end	Night	38% 7% 17% 23% 15%	2651
August	1st to 10th	Night	43% 7% 16% 26% 8%	2496
	11th to 20th	Night	42% 7% 17% 28% 7%	2866
	21st to end	Night	40% 7% 15% 23% 12% 2	3476
September	1st to 10th	Night	39% 7% 11% 26% 15% 1	1900
	11th to 20th	Night	35% 6% 13% 33% 12% 1	1938
	21st to end	Night	41% 6% 13% 27% 12%	2090
October	1st to 10th	Night	43% 6% 15% 27% 9%	3799
	11th to 20th	Night	45% 6% 14% 26% 9%	3779
	21st to end	Night	48% 5% 17% 19% 10%	4457
November	1st to 10th	Night	51% 5% 14% 21% 8% 1	2453
	11th to 20th	Night	53% 8% 13% 17% 8% 1	2593
	21st to end	Night	62% 6% 12% 15% 5%	2660
December	1st to 10th	Night	68% 6% 10% 13% 3	2660
	11th to 20th	Night	64% 5% 9% 16% 6% 1	3288
	21st to end	Night	70% 5% 9% 13% 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	27% 20% 30% 21% 3	180
	11th to 20th	Day	27% 27% 29% 13% 4 1	180
	21st to end	Day	16% 20% 40% 19% 5%	207
February	1st to 10th	Day	29% 30% 28% 11% 2	270
	11th to 20th	Day	25% 25% 39% 10% 1	322
	21st to end	Day	30% 19% 31% 18% 1	382
March	1st to 10th	Day	24% 20% 32% 19% 5%	460
	11th to 20th	Day	23% 25% 33% 16% 2 1	460
	21st to end	Day	31% 21% 23% 15% 8% 1	506
April	1st to 10th	Day	29% 18% 32% 16% 5%	460
	11th to 20th	Day	31% 21% 24% 15% 8% 2	452
	21st to end	Day	30% 20% 26% 15% 8% 1	460
May	1st to 10th	Day	25% 15% 34% 17% 7% 2	463
	11th to 20th	Day	19% 16% 33% 20% 10% 2	487
	21st to end	Day	18% 18% 32% 22% 9% 1	529
June	1st to 10th	Day	27% 11% 28% 24% 7% 2	490
	11th to 20th	Day	16% 14% 30% 28% 10% 2	490
	21st to end	Day	25% 11% 30% 21% 11% 3	490
July	1st to 10th	Day	14% 10% 30% 28% 16% 3	485
	11th to 20th	Day	14% 10% 31% 28% 14% 3	484
	21st to end	Day	16% 8% 30% 31% 13% 2	532
August	1st to 10th	Day	16% 8% 26% 31% 16% 3	486
	11th to 20th	Day	14% 8% 23% 32% 16% 7%	479
	21st to end	Day	14% 11% 27% 27% 15% 6%	539
September	1st to 10th	Day	16% 12% 28% 21% 16% 7%	490
	11th to 20th	Day	12% 10% 22% 24% 20% 11%	490
	21st to end	Day	18% 13% 30% 18% 16% 4	490
October	1st to 10th	Day	23% 15% 26% 20% 12% 3	490
	11th to 20th	Day	25% 19% 29% 18% 9% 1	490
	21st to end	Day	32% 13% 31% 20% 5%	434
November	1st to 10th	Day	26% 18% 27% 21% 7% 1	374
	11th to 20th	Day	26% 21% 33% 15% 5%	242
	21st to end	Day	28% 22% 28% 16% 5% 1	180
December	1st to 10th	Day	29% 18% 33% 16% 4	180
	11th to 20th	Day	28% 24% 33% 12% 1 1	180
	21st to end	Day	32% 24% 29% 13% 3	198
January	1st to 10th	Night	27% 17% 35% 17% 4	760
	11th to 20th	Night	28% 14% 33% 20% 5% 1	760
	21st to end	Night	20% 14% 35% 26% 5%	836
February	1st to 10th	Night	21% 16% 37% 22% 3	760
	11th to 20th	Night	22% 18% 37% 20% 4	743
	21st to end	Night	24% 15% 33% 25% 3	628
March	1st to 10th	Night	23% 16% 34% 23% 4	760
	11th to 20th	Night	26% 17% 32% 21% 3	760
	21st to end	Night	23% 15% 29% 26% 7%	836
April	1st to 10th	Night	29% 13% 30% 25% 3	760
	11th to 20th	Night	26% 15% 32% 21% 6%	751
	21st to end	Night	29% 13% 29% 22% 7%	656
May	1st to 10th	Night	26% 8% 32% 25% 8% 2	380
	11th to 20th	Night	23% 9% 32% 27% 9% 1	374
	21st to end	Night	15% 8% 38% 29% 9%	411
June	1st to 10th	Night	19% 8% 29% 36% 8% 1	380
	11th to 20th	Night	19% 6% 28% 34% 12% 1	380
	21st to end	Night	19% 5% 29% 29% 16% 1	380
July	1st to 10th	Night	11% 7% 29% 36% 16% 1	370
	11th to 20th	Night	13% 4 29% 39% 15%	368
	21st to end	Night	14% 5% 29% 37% 14% 1	416
August	1st to 10th	Night	14% 3 24% 39% 19% 1	378
	11th to 20th	Night	14% 4 22% 35% 22% 2	592
	21st to end	Night	15% 5% 27% 34% 17% 2	836
September	1st to 10th	Night	14% 5% 29% 35% 15% 1	760
	11th to 20th	Night	17% 7% 21% 32% 21% 3	760
	21st to end	Night	19% 7% 28% 25% 19% 2	760
October	1st to 10th	Night	23% 8% 30% 26% 13% 1	760
	11th to 20th	Night	24% 12% 30% 25% 10%	760
	21st to end	Night	27% 14% 31% 24% 5%	836
November	1st to 10th	Night	26% 14% 26% 25% 8% 1	755
	11th to 20th	Night	23% 17% 33% 17% 9%	760
	21st to end	Night	27% 16% 29% 21% 7%	760
December	1st to 10th	Night	29% 15% 32% 19% 4	760
	11th to 20th	Night	30% 18% 28% 18% 4 1	760
	21st to end	Night	35% 17% 29% 16% 3	836

Page generated at 2024-11-01 22:47:33. Version ac07

Copyright © 2024 Attilla Danko.