Barry's Bay
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Barry's Bay clear sky chart from 2005-11-06 to 2024-11-05.

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	15% 11% 4 9% 5% 5% 4 4 5% 6% 32%	101584
	Night	15% 12% 4 9% 6% 5% 4 3 5% 6% 30%	97434
Transparency	Day	52% 6% 11% 21% 10% 1	105132
	Night	53% 6% 12% 19% 9% 1	101975
Seeing	Day	23% 18% 31% 19% 8% 2	14379
	Night	22% 15% 31% 23% 8% 1	23555

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	13% 18% 7% 14% 8% 5% 4 3 4 4 19%	2517
	11th to 20th	Day	11% 12% 7% 20% 9% 5% 4 3 5% 6% 16%	2520
	21st to end	Day	15% 23% 8% 14% 5% 4 4 2 3 3 18%	3042
February	1st to 10th	Day	10% 16% 6% 16% 9% 5% 5% 4 4 5% 21%	1710
	11th to 20th	Day	11% 15% 7% 13% 6% 6% 5% 3 5% 5% 25%	1663
	21st to end	Day	16% 16% 4 9% 7% 5% 5% 4 5% 4 23%	1489
March	1st to 10th	Day	15% 17% 5% 10% 6% 4 4 3 4 6% 27%	3296
	11th to 20th	Day	10% 18% 6% 12% 6% 5% 4 4 5% 5% 26%	3480
	21st to end	Day	11% 9% 4 8% 5% 5% 3 3 4 5% 43%	3900
April	1st to 10th	Day	20% 15% 3 8% 5% 4 4 4 4 5% 28%	2280
	11th to 20th	Day	21% 12% 3 7% 4 4 3 3 4 5% 35%	2261
	21st to end	Day	21% 11% 3 7% 5% 3 5% 2 4 5% 33%	2470
May	1st to 10th	Day	18% 10% 3 8% 5% 4 4 4 5% 6% 33%	4360
	11th to 20th	Day	15% 9% 4 7% 4 5% 4 4 5% 7% 35%	4398
	21st to end	Day	16% 6% 3 7% 5% 5% 4 3 4 7% 39%	4837
June	1st to 10th	Day	20% 10% 3 7% 5% 5% 5% 3 5% 7% 30%	2660
	11th to 20th	Day	15% 7% 2 6% 4 4 5% 4 6% 8% 37%	2660
	21st to end	Day	16% 8% 3 7% 5% 5% 5% 5% 6% 7% 34%	2660
July	1st to 10th	Day	13% 7% 3 7% 5% 5% 5% 4 6% 10% 33%	4440
	11th to 20th	Day	13% 6% 2 6% 5% 5% 5% 4 6% 8% 40%	4440
	21st to end	Day	10% 6% 2 7% 4 4 4 4 5% 8% 44%	4814
August	1st to 10th	Day	14% 8% 3 9% 5% 5% 5% 4 5% 7% 33%	4151
	11th to 20th	Day	17% 7% 2 6% 4 5% 5% 4 7% 9% 33%	4044
	21st to end	Day	10% 5% 2 6% 5% 5% 6% 5% 7% 9% 40%	4276
September	1st to 10th	Day	15% 7% 2 6% 4 5% 5% 4 6% 8% 40%	2280
	11th to 20th	Day	14% 7% 2 6% 5% 4 3 3 5% 7% 45%	2280
	21st to end	Day	18% 9% 3 7% 5% 4 5% 3 4 7% 35%	1986
October	1st to 10th	Day	19% 10% 3 8% 5% 4 4 4 4 6% 34%	1900
	11th to 20th	Day	22% 15% 4 9% 4 4 4 4 4 5% 25%	1900
	21st to end	Day	26% 15% 4 9% 5% 5% 4 3 4 5% 21%	2024
November	1st to 10th	Day	15% 13% 4 9% 4 4 4 3 4 7% 32%	1608
	11th to 20th	Day	15% 17% 6% 10% 7% 4 4 3 5% 5% 25%	1520
	21st to end	Day	20% 20% 6% 12% 7% 4 4 3 4 5% 15%	1520
December	1st to 10th	Day	18% 21% 8% 12% 7% 5% 3 3 4 4 15%	1520
	11th to 20th	Day	17% 18% 6% 12% 6% 5% 4 3 5% 4 20%	1906
	21st to end	Day	23% 22% 6% 15% 5% 2 2 2 2 4 17%	2772
January	1st to 10th	Night	14% 19% 8% 15% 7% 6% 5% 3 4 4 15%	4429
	11th to 20th	Night	10% 14% 5% 16% 9% 8% 7% 4 5% 5% 17%	4440
	21st to end	Night	14% 18% 9% 13% 6% 7% 4 3 4 4 18%	4596
February	1st to 10th	Night	12% 16% 6% 13% 8% 6% 5% 3 5% 6% 19%	2470
	11th to 20th	Night	11% 15% 6% 11% 6% 5% 5% 3 5% 5% 27%	2403
	21st to end	Night	11% 16% 4 11% 6% 5% 4 4 5% 6% 27%	1965
March	1st to 10th	Night	17% 13% 4 10% 6% 4 4 3 4 5% 31%	3542
	11th to 20th	Night	13% 17% 5% 11% 6% 5% 4 3 6% 5% 24%	3479
	21st to end	Night	10% 10% 4 10% 6% 4 4 4 6% 7% 35%	3731
April	1st to 10th	Night	19% 13% 4 8% 6% 4 4 4 3 5% 31%	1900
	11th to 20th	Night	19% 12% 3 6% 4 4 3 3 4 6% 37%	1875
	21st to end	Night	20% 11% 3 8% 5% 4 4 4 4 4 32%	1720
May	1st to 10th	Night	18% 9% 2 7% 4 4 5% 4 6% 6% 36%	2578
	11th to 20th	Night	17% 8% 3 7% 5% 4 4 4 6% 7% 35%	2495
	21st to end	Night	11% 7% 3 7% 6% 4 5% 4 5% 7% 42%	2738
June	1st to 10th	Night	16% 7% 3 7% 5% 4 5% 5% 5% 7% 35%	1520
	11th to 20th	Night	15% 5% 2 6% 3 4 5% 3 5% 8% 43%	1520
	21st to end	Night	17% 8% 2 6% 5% 5% 5% 2 7% 6% 36%	1520
July	1st to 10th	Night	10% 8% 3 6% 6% 5% 5% 4 6% 7% 40%	2520
	11th to 20th	Night	13% 6% 2 6% 5% 4 4 4 5% 7% 44%	2520
	21st to end	Night	9% 6% 2 6% 4 4 4 4 6% 8% 48%	2739
August	1st to 10th	Night	11% 5% 2 7% 4 5% 4 5% 6% 8% 43%	2761
	11th to 20th	Night	15% 6% 2 6% 4 4 4 4 5% 7% 43%	2785
	21st to end	Night	13% 5% 2 5% 4 4 5% 4 6% 8% 44%	3347
September	1st to 10th	Night	13% 5% 2 4 5% 4 4 4 4 7% 48%	1900
	11th to 20th	Night	14% 6% 2 5% 4 4 3 3 4 6% 50%	1900
	21st to end	Night	16% 8% 3 6% 4 4 5% 3 4 6% 41%	2190
October	1st to 10th	Night	20% 8% 3 6% 3 3 4 3 4 6% 40%	2280
	11th to 20th	Night	20% 12% 3 8% 5% 4 4 4 4 6% 29%	2280
	21st to end	Night	22% 15% 4 9% 6% 4 4 3 5% 5% 25%	2574
November	1st to 10th	Night	16% 13% 4 9% 5% 4 4 3 5% 5% 31%	2565
	11th to 20th	Night	16% 14% 5% 11% 7% 5% 4 3 5% 6% 24%	2660
	21st to end	Night	18% 17% 5% 13% 7% 5% 4 3 4 5% 19%	2660
December	1st to 10th	Night	17% 21% 7% 12% 7% 5% 4 4 4 5% 14%	2660
	11th to 20th	Night	16% 19% 6% 12% 6% 5% 3 3 3 5% 22%	3288
	21st to end	Night	24% 21% 6% 15% 6% 4 3 2 3 3 13%	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	68% 7% 11% 8% 6%	2518
	11th to 20th	Day	68% 6% 8% 11% 6% 1	2520
	21st to end	Day	73% 4 6% 10% 6% 1	3042
February	1st to 10th	Day	66% 4 8% 15% 5% 1	1710
	11th to 20th	Day	60% 5% 11% 13% 9% 1	1672
	21st to end	Day	61% 6% 9% 13% 10% 1	1489
March	1st to 10th	Day	59% 5% 10% 13% 11% 1	3299
	11th to 20th	Day	60% 5% 12% 14% 9% 1	3480
	21st to end	Day	44% 5% 8% 23% 16% 4	3900
April	1st to 10th	Day	57% 5% 7% 18% 10% 3	2280
	11th to 20th	Day	53% 4 7% 22% 13% 2	2261
	21st to end	Day	54% 5% 7% 17% 14% 3	2470
May	1st to 10th	Day	50% 6% 9% 21% 11% 2	4374
	11th to 20th	Day	46% 7% 11% 24% 10% 1	4402
	21st to end	Day	45% 7% 11% 19% 16% 3	4837
June	1st to 10th	Day	53% 6% 10% 19% 11% 1	2660
	11th to 20th	Day	43% 7% 12% 23% 13% 2	2660
	21st to end	Day	47% 8% 12% 20% 12% 1	2660
July	1st to 10th	Day	44% 6% 14% 25% 10% 1	4370
	11th to 20th	Day	39% 6% 15% 29% 10%	4365
	21st to end	Day	37% 7% 11% 33% 12%	4661
August	1st to 10th	Day	49% 6% 13% 23% 9% 1	4137
	11th to 20th	Day	46% 6% 15% 25% 7% 1	4083
	21st to end	Day	38% 8% 12% 32% 10% 1	4276
September	1st to 10th	Day	41% 7% 13% 27% 11% 1	2280
	11th to 20th	Day	40% 6% 12% 30% 13%	2280
	21st to end	Day	49% 6% 12% 23% 10%	1986
October	1st to 10th	Day	51% 5% 10% 27% 7%	3160
	11th to 20th	Day	54% 4 11% 21% 10%	3140
	21st to end	Day	61% 5% 13% 15% 4	3314
November	1st to 10th	Day	52% 6% 14% 21% 7%	1608
	11th to 20th	Day	61% 7% 11% 12% 7% 1	1520
	21st to end	Day	71% 5% 10% 9% 5% 1	1520
December	1st to 10th	Day	74% 5% 7% 9% 4	1520
	11th to 20th	Day	66% 7% 8% 10% 8% 1	1906
	21st to end	Day	75% 3 5% 14% 3	2772
January	1st to 10th	Night	71% 7% 10% 9% 3	4429
	11th to 20th	Night	67% 7% 10% 10% 4	4440
	21st to end	Night	71% 5% 9% 9% 6%	4596
February	1st to 10th	Night	65% 6% 10% 13% 6% 1	2470
	11th to 20th	Night	59% 5% 11% 18% 7% 1	2405
	21st to end	Night	57% 7% 9% 18% 9% 1	1965
March	1st to 10th	Night	57% 5% 11% 17% 9% 1	3552
	11th to 20th	Night	58% 7% 12% 15% 7% 1	3480
	21st to end	Night	46% 7% 10% 21% 15% 2	3731
April	1st to 10th	Night	56% 4 8% 18% 11% 2	1900
	11th to 20th	Night	50% 5% 7% 23% 13% 1	1875
	21st to end	Night	54% 5% 8% 16% 16% 2	1720
May	1st to 10th	Night	46% 8% 12% 22% 10% 2	2584
	11th to 20th	Night	45% 10% 11% 23% 10% 1	2496
	21st to end	Night	40% 8% 11% 24% 15% 2	2739
June	1st to 10th	Night	45% 8% 12% 21% 12% 1	1520
	11th to 20th	Night	39% 6% 11% 27% 15% 2	1520
	21st to end	Night	46% 7% 14% 20% 13% 1	1520
July	1st to 10th	Night	41% 7% 17% 21% 14% 1	2480
	11th to 20th	Night	39% 5% 14% 32% 10%	2472
	21st to end	Night	34% 7% 14% 32% 14%	2651
August	1st to 10th	Night	37% 7% 16% 26% 13% 1	2751
	11th to 20th	Night	40% 6% 17% 28% 8%	2812
	21st to end	Night	36% 7% 15% 30% 10% 2	3347
September	1st to 10th	Night	36% 7% 14% 29% 13% 1	1900
	11th to 20th	Night	36% 6% 13% 33% 12%	1900
	21st to end	Night	45% 6% 11% 28% 10%	2190
October	1st to 10th	Night	40% 5% 12% 29% 14%	3800
	11th to 20th	Night	50% 5% 15% 19% 11%	3779
	21st to end	Night	54% 6% 18% 17% 6%	4234
November	1st to 10th	Night	54% 6% 14% 18% 8%	2565
	11th to 20th	Night	61% 6% 10% 15% 7% 1	2660
	21st to end	Night	67% 7% 10% 12% 3	2660
December	1st to 10th	Night	72% 6% 8% 10% 4	2660
	11th to 20th	Night	65% 5% 9% 13% 7% 1	3288
	21st to end	Night	77% 3 6% 10% 3	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	20% 26% 35% 16% 3 1	180
	11th to 20th	Day	27% 15% 37% 17% 3 1	180
	21st to end	Day	24% 19% 35% 18% 4	276
February	1st to 10th	Day	25% 31% 33% 8% 2 1	270
	11th to 20th	Day	25% 28% 41% 6%	270
	21st to end	Day	32% 24% 32% 12% 1	301
March	1st to 10th	Day	25% 25% 34% 14% 2	460
	11th to 20th	Day	25% 19% 34% 17% 4 1	460
	21st to end	Day	29% 23% 31% 11% 5% 1	506
April	1st to 10th	Day	29% 22% 30% 13% 5% 1	460
	11th to 20th	Day	35% 21% 21% 13% 7% 2	452
	21st to end	Day	29% 20% 31% 12% 6% 1	460
May	1st to 10th	Day	26% 18% 28% 18% 8% 2	463
	11th to 20th	Day	20% 18% 30% 21% 9% 3	487
	21st to end	Day	17% 20% 32% 20% 9% 2	529
June	1st to 10th	Day	23% 14% 37% 19% 8%	490
	11th to 20th	Day	18% 15% 32% 22% 10% 2	490
	21st to end	Day	20% 15% 33% 20% 10% 2	490
July	1st to 10th	Day	11% 10% 33% 35% 9% 2	485
	11th to 20th	Day	14% 12% 36% 24% 12% 2	484
	21st to end	Day	14% 10% 35% 29% 10% 3	532
August	1st to 10th	Day	15% 9% 31% 29% 12% 4	486
	11th to 20th	Day	15% 9% 29% 25% 18% 5%	479
	21st to end	Day	14% 13% 31% 26% 11% 5%	539
September	1st to 10th	Day	17% 14% 30% 22% 13% 5%	490
	11th to 20th	Day	14% 12% 23% 23% 20% 8%	490
	21st to end	Day	19% 16% 25% 22% 13% 5%	490
October	1st to 10th	Day	26% 18% 25% 17% 11% 4	490
	11th to 20th	Day	28% 25% 27% 15% 5% 1	490
	21st to end	Day	34% 17% 29% 16% 3	504
November	1st to 10th	Day	26% 20% 32% 16% 5%	278
	11th to 20th	Day	29% 24% 31% 10% 6% 1	180
	21st to end	Day	32% 22% 36% 7% 2 1	180
December	1st to 10th	Day	32% 16% 36% 13% 2	180
	11th to 20th	Day	32% 30% 24% 11% 2 1	180
	21st to end	Day	32% 25% 27% 11% 4 1	198
January	1st to 10th	Night	23% 20% 37% 16% 4 1	760
	11th to 20th	Night	26% 19% 30% 20% 5% 1	760
	21st to end	Night	17% 16% 37% 23% 7%	836
February	1st to 10th	Night	19% 20% 40% 17% 3	760
	11th to 20th	Night	20% 20% 40% 16% 4	743
	21st to end	Night	22% 22% 32% 21% 3	628
March	1st to 10th	Night	22% 21% 34% 19% 4	760
	11th to 20th	Night	22% 20% 33% 19% 5% 1	760
	21st to end	Night	19% 17% 35% 21% 7%	836
April	1st to 10th	Night	28% 16% 32% 20% 4	760
	11th to 20th	Night	25% 19% 30% 18% 8%	751
	21st to end	Night	23% 15% 27% 25% 9%	580
May	1st to 10th	Night	19% 12% 29% 28% 11% 1	418
	11th to 20th	Night	21% 11% 34% 28% 7%	374
	21st to end	Night	12% 10% 36% 29% 11%	411
June	1st to 10th	Night	17% 8% 36% 33% 5% 1	380
	11th to 20th	Night	19% 8% 31% 30% 10% 1	380
	21st to end	Night	19% 11% 29% 29% 12%	380
July	1st to 10th	Night	10% 6% 36% 34% 14% 1	370
	11th to 20th	Night	14% 6% 27% 38% 14% 1	368
	21st to end	Night	9% 7% 34% 37% 11% 1	416
August	1st to 10th	Night	11% 6% 25% 36% 21% 1	529
	11th to 20th	Night	11% 4 24% 38% 20% 3	564
	21st to end	Night	13% 8% 29% 32% 16% 2	759
September	1st to 10th	Night	17% 7% 30% 28% 17% 2	760
	11th to 20th	Night	17% 8% 25% 27% 21% 3	760
	21st to end	Night	19% 12% 22% 27% 17% 2	760
October	1st to 10th	Night	24% 11% 29% 21% 12% 2	760
	11th to 20th	Night	26% 17% 31% 18% 8% 1	760
	21st to end	Night	30% 19% 26% 20% 5%	836
November	1st to 10th	Night	26% 16% 29% 22% 5% 1	760
	11th to 20th	Night	22% 23% 30% 15% 8% 1	760
	21st to end	Night	29% 19% 28% 20% 4	760
December	1st to 10th	Night	29% 19% 33% 14% 5%	760
	11th to 20th	Night	26% 20% 31% 19% 3 1	760
	21st to end	Night	33% 18% 28% 18% 3 1	836

Page generated at 2024-11-03 02:11:22. Version ac07

Copyright © 2024 Attilla Danko.