Pigeon Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pigeon Lake clear sky chart from 2005-11-06 to 2026-03-03.

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	9% 9% 3 9% 5% 5% 5% 4 6% 8% 36%	135467
	Night	8% 11% 4 10% 6% 5% 5% 4 6% 7% 33%	134394
Transparency	Day	45% 5% 17% 23% 9% 1	135166
	Night	49% 5% 15% 21% 10% 1	134274
Seeing	Day	14% 6% 25% 30% 19% 7%	17349
	Night	13% 6% 30% 34% 15% 2	26185

By Month

Percentage Cloud Cover NW (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	5% 12% 5% 13% 8% 6% 6% 4 6% 7% 29%	4125
	11th to 20th	Day	4 9% 3 10% 6% 5% 5% 6% 7% 9% 36%	4119
	21st to end	Day	5% 11% 5% 11% 5% 5% 6% 4 6% 7% 35%	5020
February	1st to 10th	Day	8% 13% 4 12% 7% 6% 6% 4 8% 7% 26%	1680
	11th to 20th	Day	4 14% 5% 13% 5% 6% 5% 5% 7% 6% 30%	1770
	21st to end	Day	2 14% 5% 13% 8% 8% 7% 6% 6% 8% 24%	1651
March	1st to 10th	Day	3 9% 4 12% 7% 6% 6% 4 6% 8% 35%	4539
	11th to 20th	Day	5% 11% 4 9% 6% 4 4 4 6% 8% 38%	4906
	21st to end	Day	9% 18% 6% 12% 5% 5% 5% 4 6% 7% 25%	5617
April	1st to 10th	Day	8% 13% 4 9% 7% 5% 5% 5% 7% 8% 29%	2472
	11th to 20th	Day	11% 13% 4 9% 5% 5% 5% 6% 7% 8% 28%	2570
	21st to end	Day	11% 10% 3 9% 6% 5% 6% 5% 6% 8% 31%	2600
May	1st to 10th	Day	12% 9% 3 8% 5% 5% 5% 4 5% 6% 37%	6564
	11th to 20th	Day	13% 11% 4 10% 6% 5% 6% 5% 7% 8% 25%	6734
	21st to end	Day	11% 7% 2 7% 4 5% 5% 4 6% 9% 38%	7405
June	1st to 10th	Day	16% 8% 3 6% 5% 5% 5% 4 8% 9% 32%	3000
	11th to 20th	Day	18% 10% 3 9% 6% 6% 7% 5% 6% 6% 25%	3081
	21st to end	Day	10% 6% 2 6% 5% 6% 5% 5% 8% 9% 38%	3200
July	1st to 10th	Day	9% 5% 2 5% 4 4 5% 4 6% 10% 48%	6926
	11th to 20th	Day	11% 5% 2 7% 5% 5% 5% 4 6% 8% 42%	6780
	21st to end	Day	12% 6% 2 6% 5% 5% 5% 5% 6% 9% 41%	7376
August	1st to 10th	Day	12% 7% 2 7% 4 5% 5% 4 6% 8% 41%	4577
	11th to 20th	Day	9% 6% 2 6% 5% 5% 5% 4 7% 10% 42%	4311
	21st to end	Day	11% 5% 2 6% 5% 5% 5% 4 6% 9% 42%	4664
September	1st to 10th	Day	12% 5% 2 6% 4 4 4 4 6% 8% 44%	2515
	11th to 20th	Day	15% 8% 2 5% 3 4 4 3 5% 7% 45%	2208
	21st to end	Day	10% 7% 2 6% 5% 6% 5% 3 7% 7% 42%	2200
October	1st to 10th	Day	9% 9% 3 9% 5% 4 4 4 6% 7% 40%	3441
	11th to 20th	Day	10% 11% 3 9% 4 5% 5% 3 6% 9% 35%	2939
	21st to end	Day	8% 11% 3 8% 6% 6% 5% 4 5% 7% 38%	3200
November	1st to 10th	Day	9% 16% 4 10% 8% 6% 5% 4 7% 7% 25%	1663
	11th to 20th	Day	6% 13% 4 11% 7% 4 6% 4 5% 6% 33%	1497
	21st to end	Day	5% 11% 5% 12% 7% 8% 4 4 7% 9% 28%	1470
December	1st to 10th	Day	10% 16% 5% 11% 7% 6% 6% 4 6% 7% 23%	2360
	11th to 20th	Day	7% 13% 5% 14% 8% 6% 5% 5% 6% 8% 24%	2712
	21st to end	Day	3 8% 3 10% 6% 5% 6% 4 6% 9% 41%	3575
January	1st to 10th	Night	7% 13% 6% 15% 9% 7% 5% 4 5% 6% 25%	8768
	11th to 20th	Night	3 9% 5% 11% 7% 5% 5% 5% 7% 7% 38%	8779
	21st to end	Night	6% 12% 5% 11% 6% 5% 5% 4 6% 8% 32%	9216
February	1st to 10th	Night	5% 13% 5% 12% 8% 7% 6% 5% 5% 7% 27%	2940
	11th to 20th	Night	5% 14% 4 11% 7% 7% 6% 5% 7% 7% 27%	2736
	21st to end	Night	5% 12% 5% 12% 7% 6% 6% 5% 6% 7% 29%	2153
March	1st to 10th	Night	4 10% 4 11% 6% 6% 6% 4 7% 9% 34%	5400
	11th to 20th	Night	5% 11% 3 10% 6% 7% 7% 6% 7% 9% 29%	5093
	21st to end	Night	9% 18% 6% 14% 7% 5% 5% 3 6% 6% 23%	5344
April	1st to 10th	Night	8% 10% 4 10% 7% 6% 6% 5% 8% 7% 28%	1928
	11th to 20th	Night	10% 13% 4 9% 8% 5% 6% 5% 6% 7% 27%	1781
	21st to end	Night	12% 11% 3 9% 5% 4 5% 4 6% 8% 34%	1800
May	1st to 10th	Night	17% 9% 3 7% 5% 4 4 4 5% 7% 36%	3383
	11th to 20th	Night	14% 9% 3 11% 7% 6% 6% 5% 6% 7% 25%	3159
	21st to end	Night	12% 9% 3 7% 5% 5% 5% 4 6% 7% 36%	3470
June	1st to 10th	Night	18% 7% 3 10% 4 5% 5% 5% 8% 7% 28%	1400
	11th to 20th	Night	18% 9% 4 9% 6% 7% 5% 6% 6% 6% 23%	1311
	21st to end	Night	12% 8% 2 7% 5% 6% 6% 6% 9% 7% 34%	1200
July	1st to 10th	Night	9% 6% 2 7% 4 5% 5% 4 7% 9% 42%	3029
	11th to 20th	Night	12% 7% 3 7% 5% 5% 6% 4 6% 9% 35%	3180
	21st to end	Night	12% 6% 2 6% 4 5% 5% 4 7% 7% 40%	3467
August	1st to 10th	Night	15% 6% 2 6% 5% 4 5% 5% 7% 9% 37%	2571
	11th to 20th	Night	11% 7% 3 6% 5% 5% 5% 5% 7% 9% 37%	2742
	21st to end	Night	13% 4 2 6% 5% 5% 4 4 7% 9% 41%	3245
September	1st to 10th	Night	12% 5% 2 7% 4 4 5% 3 6% 7% 45%	1881
	11th to 20th	Night	12% 6% 3 7% 4 5% 4 4 5% 7% 44%	2191
	21st to end	Night	10% 7% 3 6% 4 4 4 3 7% 8% 43%	2200
October	1st to 10th	Night	9% 8% 3 7% 5% 4 6% 4 6% 8% 40%	3754
	11th to 20th	Night	10% 8% 4 7% 4 4 6% 4 6% 9% 37%	4206
	21st to end	Night	6% 11% 4 9% 6% 5% 5% 4 6% 7% 36%	4600
November	1st to 10th	Night	11% 16% 5% 10% 6% 5% 5% 4 5% 7% 27%	2835
	11th to 20th	Night	7% 13% 5% 11% 7% 6% 5% 4 7% 7% 28%	3119
	21st to end	Night	7% 13% 4 10% 8% 5% 6% 5% 6% 8% 28%	3150
December	1st to 10th	Night	10% 18% 5% 11% 7% 6% 5% 4 5% 6% 25%	5040
	11th to 20th	Night	7% 15% 7% 12% 7% 6% 5% 4 6% 7% 24%	5700
	21st to end	Night	3 8% 4 10% 6% 6% 5% 4 6% 8% 41%	7623

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% 4 12% 17% 12% 1	4125
	11th to 20th	Day	43% 3 14% 17% 19% 3	4140
	21st to end	Day	49% 4 17% 25% 5%	5021
February	1st to 10th	Day	54% 4 14% 15% 11% 1	1680
	11th to 20th	Day	52% 5% 14% 19% 10% 1	1778
	21st to end	Day	57% 5% 12% 18% 8% 1	1651
March	1st to 10th	Day	47% 4 16% 19% 14%	4539
	11th to 20th	Day	43% 5% 14% 23% 15%	4907
	21st to end	Day	58% 5% 9% 19% 9% 1	5617
April	1st to 10th	Day	49% 7% 14% 20% 8% 1	2472
	11th to 20th	Day	51% 5% 12% 22% 8%	2570
	21st to end	Day	49% 6% 14% 24% 7% 2	2600
May	1st to 10th	Day	47% 4 10% 24% 15% 1	6564
	11th to 20th	Day	53% 6% 14% 21% 6%	6738
	21st to end	Day	41% 4 21% 24% 9% 1	7406
June	1st to 10th	Day	46% 5% 17% 24% 8% 1	3000
	11th to 20th	Day	55% 6% 17% 16% 6%	3081
	21st to end	Day	38% 7% 24% 25% 6% 1	3200
July	1st to 10th	Day	32% 5% 19% 31% 12% 1	6852
	11th to 20th	Day	39% 5% 18% 30% 8%	6699
	21st to end	Day	39% 6% 20% 24% 9% 1	7169
August	1st to 10th	Day	40% 6% 20% 32% 2	4559
	11th to 20th	Day	36% 6% 23% 28% 7%	4353
	21st to end	Day	37% 6% 26% 25% 6%	4663
September	1st to 10th	Day	37% 5% 21% 28% 7% 2	2515
	11th to 20th	Day	39% 4 18% 30% 9%	2208
	21st to end	Day	40% 6% 17% 26% 10% 2	2200
October	1st to 10th	Day	42% 4 21% 26% 5% 1	3441
	11th to 20th	Day	46% 4 14% 25% 11%	2939
	21st to end	Day	46% 4 16% 28% 6%	3200
November	1st to 10th	Day	56% 5% 14% 17% 6% 1	1663
	11th to 20th	Day	51% 5% 15% 19% 9%	1497
	21st to end	Day	52% 5% 16% 18% 7% 2	1470
December	1st to 10th	Day	60% 5% 17% 12% 5% 1	2360
	11th to 20th	Day	58% 5% 16% 15% 5% 1	2714
	21st to end	Day	39% 4 13% 24% 18% 2	3575
January	1st to 10th	Night	60% 3 11% 15% 10% 1	8769
	11th to 20th	Night	45% 4 15% 17% 16% 3	8820
	21st to end	Night	49% 3 19% 20% 7%	9216
February	1st to 10th	Night	56% 3 11% 19% 10% 1	2940
	11th to 20th	Night	53% 6% 12% 16% 12% 1	2738
	21st to end	Night	52% 4 11% 21% 11% 1	2153
March	1st to 10th	Night	45% 5% 16% 22% 12%	5400
	11th to 20th	Night	48% 5% 15% 20% 11% 1	5093
	21st to end	Night	61% 5% 7% 18% 8%	5344
April	1st to 10th	Night	50% 8% 12% 19% 10% 1	1928
	11th to 20th	Night	53% 5% 12% 20% 9% 2	1781
	21st to end	Night	48% 5% 14% 23% 10% 1	1800
May	1st to 10th	Night	48% 5% 8% 21% 16% 2	3380
	11th to 20th	Night	55% 6% 15% 18% 6%	3159
	21st to end	Night	46% 4 19% 22% 9% 1	3470
June	1st to 10th	Night	51% 6% 14% 20% 8% 1	1400
	11th to 20th	Night	58% 6% 16% 15% 5%	1311
	21st to end	Night	44% 8% 21% 22% 5% 1	1200
July	1st to 10th	Night	37% 6% 21% 21% 14% 1	2994
	11th to 20th	Night	44% 6% 15% 27% 7%	3138
	21st to end	Night	40% 6% 21% 24% 7%	3369
August	1st to 10th	Night	42% 6% 21% 29% 2	2564
	11th to 20th	Night	41% 7% 22% 22% 8% 1	2766
	21st to end	Night	38% 5% 21% 29% 7%	3245
September	1st to 10th	Night	37% 5% 17% 27% 12% 2	1881
	11th to 20th	Night	40% 4 15% 28% 11% 3	2191
	21st to end	Night	37% 5% 16% 26% 13% 2	2200
October	1st to 10th	Night	42% 4 19% 26% 8%	3754
	11th to 20th	Night	43% 4 13% 31% 8% 1	4206
	21st to end	Night	46% 5% 16% 26% 7% 1	4600
November	1st to 10th	Night	56% 5% 12% 19% 8% 1	2835
	11th to 20th	Night	53% 5% 14% 18% 9% 1	3119
	21st to end	Night	52% 6% 15% 18% 6% 2	3150
December	1st to 10th	Night	60% 5% 13% 15% 5% 1	5040
	11th to 20th	Night	58% 4 16% 15% 6%	5697
	21st to end	Night	40% 3 12% 26% 16% 3	7623

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	7% 5% 34% 33% 16% 5%	220
	11th to 20th	Day	11% 8% 39% 25% 10% 7%	220
	21st to end	Day	11% 9% 33% 29% 13% 5%	242
February	1st to 10th	Day	14% 8% 34% 29% 12% 3	220
	11th to 20th	Day	12% 6% 32% 34% 13% 3	290
	21st to end	Day	8% 7% 37% 28% 14% 5%	367
March	1st to 10th	Day	11% 8% 31% 29% 17% 3	509
	11th to 20th	Day	10% 5% 34% 31% 14% 6%	500
	21st to end	Day	15% 7% 29% 27% 18% 4	550
April	1st to 10th	Day	11% 10% 34% 29% 14% 3	500
	11th to 20th	Day	16% 8% 24% 30% 15% 6%	492
	21st to end	Day	16% 8% 26% 28% 17% 5%	500
May	1st to 10th	Day	16% 7% 21% 33% 17% 5%	618
	11th to 20th	Day	12% 6% 20% 34% 21% 7%	725
	21st to end	Day	16% 4 19% 30% 22% 8%	789
June	1st to 10th	Day	16% 7% 23% 32% 16% 4	730
	11th to 20th	Day	20% 5% 21% 26% 22% 6%	811
	21st to end	Day	12% 4 19% 30% 25% 10%	930
July	1st to 10th	Day	13% 3 17% 35% 23% 9%	789
	11th to 20th	Day	13% 4 19% 30% 25% 9%	718
	21st to end	Day	12% 5% 13% 30% 27% 13%	794
August	1st to 10th	Day	11% 5% 16% 29% 25% 14%	550
	11th to 20th	Day	9% 4 23% 30% 25% 8%	517
	21st to end	Day	14% 7% 15% 26% 27% 11%	583
September	1st to 10th	Day	15% 5% 24% 26% 21% 10%	530
	11th to 20th	Day	18% 5% 18% 32% 20% 7%	530
	21st to end	Day	14% 11% 32% 24% 15% 5%	530
October	1st to 10th	Day	14% 8% 26% 29% 16% 7%	436
	11th to 20th	Day	12% 9% 32% 28% 13% 5%	330
	21st to end	Day	14% 12% 37% 25% 10% 2	363
November	1st to 10th	Day	19% 6% 33% 27% 11% 4	330
	11th to 20th	Day	13% 6% 35% 34% 9% 3	234
	21st to end	Day	8% 7% 37% 29% 14% 5%	220
December	1st to 10th	Day	13% 7% 37% 26% 11% 5%	220
	11th to 20th	Day	10% 14% 31% 30% 13% 3	220
	21st to end	Day	9% 5% 30% 34% 17% 6%	242
January	1st to 10th	Night	12% 7% 35% 30% 15% 1	1050
	11th to 20th	Night	11% 10% 37% 32% 9% 1	1050
	21st to end	Night	13% 12% 34% 30% 10% 1	1003
February	1st to 10th	Night	11% 9% 29% 33% 17% 2	840
	11th to 20th	Night	11% 6% 35% 34% 13% 1	824
	21st to end	Night	10% 7% 29% 33% 16% 5%	692
March	1st to 10th	Night	9% 5% 32% 36% 14% 3	808
	11th to 20th	Night	11% 5% 34% 33% 15% 2	800
	21st to end	Night	13% 4 28% 39% 15% 2	880
April	1st to 10th	Night	12% 7% 28% 38% 13% 2	728
	11th to 20th	Night	17% 5% 28% 36% 13% 1	593
	21st to end	Night	16% 6% 25% 39% 13% 1	600
May	1st to 10th	Night	19% 6% 21% 39% 13% 3	414
	11th to 20th	Night	14% 5% 24% 36% 19% 2	394
	21st to end	Night	20% 6% 20% 35% 17% 2	433
June	1st to 10th	Night	20% 7% 25% 33% 13% 2	400
	11th to 20th	Night	21% 4 19% 37% 17% 2	400
	21st to end	Night	15% 4 19% 36% 23% 4	400
July	1st to 10th	Night	14% 2 14% 45% 24% 1	390
	11th to 20th	Night	12% 4 16% 45% 21% 2	388
	21st to end	Night	14% 3 13% 38% 29% 3	438
August	1st to 10th	Night	15% 3 18% 31% 27% 7%	398
	11th to 20th	Night	11% 4 17% 37% 27% 3	496
	21st to end	Night	13% 3 20% 40% 23% 1	660
September	1st to 10th	Night	14% 2 19% 42% 21% 2	681
	11th to 20th	Night	14% 4 21% 41% 20% 2	800
	21st to end	Night	14% 4 30% 36% 14% 2	800
October	1st to 10th	Night	15% 5% 29% 37% 14% 1	800
	11th to 20th	Night	15% 7% 34% 29% 14% 2	800
	21st to end	Night	12% 9% 36% 32% 11%	880
November	1st to 10th	Night	19% 7% 34% 31% 9% 1	990
	11th to 20th	Night	12% 7% 40% 30% 10% 2	1050
	21st to end	Night	13% 5% 39% 30% 11% 2	1050
December	1st to 10th	Night	14% 10% 34% 29% 11% 2	1050
	11th to 20th	Night	11% 6% 36% 32% 12% 1	1050
	21st to end	Night	12% 5% 34% 33% 15% 2	1155

Page generated at 2026-02-27 23:40:21. Version ac07

Copyright © 2026 Attilla Danko.