Trout Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Trout Lake clear sky chart from 2005-11-06 to 2024-11-08.

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% 8% 2 6% 4 4 4 4 5% 6% 47%	105410
	Night	11% 9% 3 6% 4 4 4 4 5% 6% 43%	102364
Transparency	Day	38% 7% 11% 22% 15% 6%	105153
	Night	42% 8% 12% 21% 12% 5%	102210
Seeing	Day	22% 19% 30% 19% 8% 2	14536
	Night	22% 13% 25% 25% 13% 2	23493

By Month

Percentage Cloud Cover SW (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% 24% 7% 10% 7% 5% 4 4 4 5% 15%	2539
	11th to 20th	Day	18% 20% 4 8% 6% 5% 4 4 4 5% 21%	2540
	21st to end	Day	28% 18% 4 10% 4 4 5% 4 4 6% 14%	2904
February	1st to 10th	Day	12% 15% 4 9% 6% 5% 5% 3 6% 7% 27%	1710
	11th to 20th	Day	14% 13% 3 7% 6% 6% 5% 4 6% 7% 29%	1665
	21st to end	Day	12% 18% 5% 8% 6% 6% 5% 4 5% 8% 25%	1533
March	1st to 10th	Day	10% 16% 5% 9% 6% 6% 7% 5% 5% 7% 25%	3166
	11th to 20th	Day	10% 11% 3 6% 4 4 4 3 4 5% 46%	3490
	21st to end	Day	12% 15% 4 9% 8% 7% 7% 5% 6% 6% 22%	3996
April	1st to 10th	Day	11% 13% 4 9% 7% 6% 6% 4 6% 8% 27%	2280
	11th to 20th	Day	10% 12% 4 8% 7% 6% 4 4 5% 6% 33%	2249
	21st to end	Day	6% 8% 3 8% 7% 6% 5% 4 6% 9% 37%	2441
May	1st to 10th	Day	10% 6% 2 6% 5% 4 5% 4 5% 6% 46%	4420
	11th to 20th	Day	5% 5% 2 4 3 3 4 3 5% 6% 61%	4377
	21st to end	Day	8% 7% 3 7% 5% 6% 6% 5% 7% 8% 38%	4813
June	1st to 10th	Day	11% 7% 2 6% 5% 5% 5% 4 6% 7% 43%	2660
	11th to 20th	Day	6% 5% 2 6% 4 5% 6% 4 6% 8% 48%	2660
	21st to end	Day	3 3 2 5% 4 3 3 3 5% 6% 63%	2660
July	1st to 10th	Day	1 1 1 2 2 2 2 2 3 4 83%	4420
	11th to 20th	Day	2 2 1 1 2 2 2 2 2 4 82%	4420
	21st to end	Day	2 1 1 2 1 1 2 2 3 4 82%	4790
August	1st to 10th	Day	1 2 1 2 2 2 3 2 4 5% 76%	4291
	11th to 20th	Day	2 2 1 4 2 3 3 4 5% 6% 69%	4026
	21st to end	Day	4 3 1 4 3 4 4 3 4 6% 64%	4225
September	1st to 10th	Day	3 2 1 2 2 3 3 3 4 6% 71%	2280
	11th to 20th	Day	5% 3 2 5% 4 4 5% 5% 5% 8% 55%	2280
	21st to end	Day	9% 5% 1 5% 4 5% 4 3 4 7% 53%	2028
October	1st to 10th	Day	5% 5% 2 5% 3 3 3 3 6% 8% 57%	3180
	11th to 20th	Day	9% 4 2 7% 5% 5% 6% 5% 7% 8% 41%	3161
	21st to end	Day	15% 9% 2 6% 5% 5% 6% 4 6% 7% 34%	3244
November	1st to 10th	Day	17% 11% 3 7% 6% 6% 5% 5% 7% 6% 26%	1680
	11th to 20th	Day	19% 14% 4 9% 6% 5% 5% 4 5% 6% 22%	1520
	21st to end	Day	13% 14% 3 9% 5% 6% 7% 5% 6% 7% 27%	1520
December	1st to 10th	Day	16% 13% 5% 10% 7% 4 5% 4 3 4 29%	1520
	11th to 20th	Day	21% 17% 5% 10% 5% 6% 5% 4 5% 6% 16%	1928
	21st to end	Day	18% 15% 4 13% 7% 5% 5% 4 5% 5% 20%	2794
January	1st to 10th	Night	18% 23% 5% 9% 5% 4 5% 4 5% 5% 16%	4406
	11th to 20th	Night	20% 14% 4 9% 5% 5% 4 4 4 6% 24%	4420
	21st to end	Night	27% 16% 4 8% 4 4 4 4 5% 6% 16%	4742
February	1st to 10th	Night	13% 15% 3 8% 6% 5% 6% 4 5% 7% 28%	2470
	11th to 20th	Night	12% 13% 3 7% 5% 5% 5% 4 6% 7% 32%	2402
	21st to end	Night	11% 15% 4 9% 6% 6% 6% 4 6% 6% 27%	1920
March	1st to 10th	Night	9% 13% 6% 8% 6% 5% 5% 5% 6% 8% 28%	3705
	11th to 20th	Night	9% 11% 2 5% 4 4 3 4 4 6% 48%	3490
	21st to end	Night	10% 13% 4 9% 8% 7% 6% 4 6% 6% 27%	3657
April	1st to 10th	Night	11% 12% 3 7% 7% 5% 4 4 6% 8% 32%	1900
	11th to 20th	Night	9% 9% 4 6% 4 5% 5% 5% 6% 7% 41%	1879
	21st to end	Night	7% 8% 2 6% 6% 4 6% 5% 8% 9% 40%	1735
May	1st to 10th	Night	10% 7% 2 6% 4 4 4 3 4 5% 52%	2540
	11th to 20th	Night	4 3 1 3 3 3 4 3 5% 7% 64%	2516
	21st to end	Night	2 6% 1 4 4 5% 6% 6% 9% 11% 47%	2762
June	1st to 10th	Night	8% 7% 3 6% 5% 5% 5% 3 6% 8% 44%	1520
	11th to 20th	Night	6% 4 2 4 4 4 4 4 6% 8% 55%	1520
	21st to end	Night	3 2 1 4 3 3 4 3 5% 6% 66%	1520
July	1st to 10th	Night	1 1 2 1 1 1 2 2 3 85%	2540
	11th to 20th	Night	1 1 1 2 1 1 2 2 3 4 82%	2540
	21st to end	Night	1 1 1 1 1 1 1 3 4 86%	2761
August	1st to 10th	Night	1 1 1 2 2 2 2 2 3 5% 78%	2639
	11th to 20th	Night	1 1 1 3 2 3 3 3 5% 5% 73%	2812
	21st to end	Night	2 3 1 3 2 2 3 3 4 5% 71%	3451
September	1st to 10th	Night	3 2 1 3 1 2 2 2 4 5% 76%	1900
	11th to 20th	Night	5% 3 1 4 3 4 4 4 5% 6% 61%	1900
	21st to end	Night	7% 3 1 4 3 3 4 3 5% 7% 59%	2150
October	1st to 10th	Night	5% 3 1 3 3 3 4 3 5% 7% 62%	3800
	11th to 20th	Night	8% 5% 2 5% 4 4 5% 4 8% 9% 46%	3777
	21st to end	Night	14% 8% 3 7% 4 4 5% 4 7% 7% 38%	4317
November	1st to 10th	Night	19% 9% 3 8% 5% 6% 5% 5% 5% 7% 29%	2555
	11th to 20th	Night	19% 12% 3 8% 5% 6% 5% 3 5% 6% 28%	2660
	21st to end	Night	13% 10% 2 7% 6% 6% 6% 5% 6% 7% 33%	2660
December	1st to 10th	Night	17% 10% 3 8% 7% 4 5% 4 5% 6% 30%	2660
	11th to 20th	Night	21% 14% 4 9% 6% 6% 5% 4 6% 5% 19%	3276
	21st to end	Night	18% 14% 6% 11% 6% 6% 5% 3 5% 6% 20%	4862

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	77% 9% 7% 6% 1	2539
	11th to 20th	Day	69% 7% 10% 12% 2 1	2540
	21st to end	Day	74% 8% 7% 7% 3	2904
February	1st to 10th	Day	59% 10% 15% 13% 3	1710
	11th to 20th	Day	54% 11% 14% 17% 4	1674
	21st to end	Day	58% 9% 14% 11% 8% 1	1533
March	1st to 10th	Day	54% 11% 9% 18% 8%	3166
	11th to 20th	Day	42% 6% 12% 34% 6%	3490
	21st to end	Day	59% 12% 11% 14% 4	3996
April	1st to 10th	Day	55% 10% 13% 17% 5%	2280
	11th to 20th	Day	50% 8% 14% 16% 11% 2	2252
	21st to end	Day	43% 11% 15% 20% 9% 2	2441
May	1st to 10th	Day	38% 8% 11% 25% 17% 1	4420
	11th to 20th	Day	24% 6% 14% 36% 19% 1	4380
	21st to end	Day	42% 12% 20% 21% 4	4814
June	1st to 10th	Day	40% 7% 15% 26% 11% 1	2660
	11th to 20th	Day	32% 9% 17% 30% 11% 1	2660
	21st to end	Day	22% 5% 15% 34% 18% 5%	2660
July	1st to 10th	Day	8% 4 7% 18% 24% 39%	4351
	11th to 20th	Day	9% 3 5% 12% 29% 42%	4345
	21st to end	Day	9% 4 6% 24% 39% 18%	4639
August	1st to 10th	Day	13% 4 6% 22% 35% 21%	4275
	11th to 20th	Day	16% 5% 10% 41% 22% 6%	4065
	21st to end	Day	23% 5% 10% 25% 33% 4	4224
September	1st to 10th	Day	14% 4 10% 32% 28% 12%	2280
	11th to 20th	Day	27% 7% 14% 25% 20% 7%	2280
	21st to end	Day	32% 5% 13% 28% 17% 5%	2028
October	1st to 10th	Day	26% 7% 11% 32% 22% 2	3180
	11th to 20th	Day	39% 9% 17% 22% 13% 1	3161
	21st to end	Day	48% 10% 9% 22% 9% 1	3244
November	1st to 10th	Day	56% 9% 12% 18% 4 1	1680
	11th to 20th	Day	64% 8% 12% 11% 3 1	1520
	21st to end	Day	57% 10% 10% 15% 7% 1	1520
December	1st to 10th	Day	62% 8% 10% 14% 5%	1520
	11th to 20th	Day	72% 9% 11% 6% 2	1928
	21st to end	Day	69% 8% 9% 11% 2	2794
January	1st to 10th	Night	73% 10% 8% 7% 2	4406
	11th to 20th	Night	65% 9% 13% 10% 3 1	4420
	21st to end	Night	72% 8% 9% 8% 2	4742
February	1st to 10th	Night	57% 8% 16% 16% 3	2470
	11th to 20th	Night	51% 11% 13% 18% 6% 1	2404
	21st to end	Night	57% 8% 12% 16% 6%	1920
March	1st to 10th	Night	51% 10% 14% 19% 6%	3705
	11th to 20th	Night	39% 7% 14% 33% 7% 1	3490
	21st to end	Night	55% 13% 12% 18% 3	3657
April	1st to 10th	Night	48% 11% 17% 16% 7% 1	1900
	11th to 20th	Night	41% 10% 18% 20% 10% 2	1879
	21st to end	Night	37% 12% 17% 23% 10% 1	1735
May	1st to 10th	Night	37% 7% 11% 25% 19% 1	2540
	11th to 20th	Night	20% 9% 13% 38% 18% 2	2516
	21st to end	Night	27% 17% 30% 21% 5%	2762
June	1st to 10th	Night	38% 7% 14% 30% 9% 2	1520
	11th to 20th	Night	27% 7% 19% 33% 13% 1	1520
	21st to end	Night	20% 5% 14% 37% 20% 5%	1520
July	1st to 10th	Night	8% 3 8% 17% 30% 35%	2500
	11th to 20th	Night	9% 3 6% 15% 26% 41%	2492
	21st to end	Night	6% 3 7% 22% 39% 24%	2674
August	1st to 10th	Night	11% 3 7% 22% 37% 21%	2631
	11th to 20th	Night	13% 5% 14% 41% 22% 6%	2839
	21st to end	Night	16% 5% 12% 29% 31% 7%	3451
September	1st to 10th	Night	13% 3 12% 30% 30% 12%	1900
	11th to 20th	Night	24% 8% 12% 27% 19% 10%	1900
	21st to end	Night	24% 7% 15% 28% 20% 6%	2150
October	1st to 10th	Night	23% 6% 9% 38% 23% 1	3800
	11th to 20th	Night	34% 8% 19% 26% 12% 2	3777
	21st to end	Night	45% 9% 9% 25% 11% 1	4317
November	1st to 10th	Night	52% 10% 12% 18% 7%	2555
	11th to 20th	Night	58% 9% 13% 14% 5% 1	2660
	21st to end	Night	51% 11% 13% 17% 7% 1	2660
December	1st to 10th	Night	58% 10% 12% 16% 4	2660
	11th to 20th	Night	68% 10% 11% 9% 2	3276
	21st to end	Night	67% 9% 9% 11% 3	4862

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	39% 20% 24% 11% 5%	180
	11th to 20th	Day	37% 18% 26% 12% 6% 1	180
	21st to end	Day	36% 19% 22% 16% 7%	269
February	1st to 10th	Day	34% 25% 21% 16% 3 1	370
	11th to 20th	Day	40% 22% 23% 12% 3	365
	21st to end	Day	38% 19% 26% 13% 4	365
March	1st to 10th	Day	32% 20% 32% 13% 3	460
	11th to 20th	Day	29% 22% 27% 15% 7% 1	460
	21st to end	Day	33% 24% 28% 11% 4	506
April	1st to 10th	Day	34% 25% 22% 11% 5% 2	460
	11th to 20th	Day	30% 28% 23% 12% 5% 2	452
	21st to end	Day	25% 27% 28% 14% 5% 1	460
May	1st to 10th	Day	21% 24% 29% 17% 6% 2	463
	11th to 20th	Day	22% 18% 30% 16% 11% 3	488
	21st to end	Day	16% 22% 30% 20% 10% 2	529
June	1st to 10th	Day	21% 22% 26% 19% 10% 2	490
	11th to 20th	Day	23% 24% 33% 13% 7% 1	490
	21st to end	Day	9% 19% 35% 25% 9% 2	490
July	1st to 10th	Day	6% 14% 47% 24% 8% 1	486
	11th to 20th	Day	6% 13% 42% 26% 11% 2	484
	21st to end	Day	5% 14% 36% 27% 13% 4	531
August	1st to 10th	Day	5% 9% 38% 28% 15% 5%	487
	11th to 20th	Day	4 11% 36% 29% 16% 5%	477
	21st to end	Day	9% 17% 35% 23% 12% 4	539
September	1st to 10th	Day	6% 15% 33% 31% 12% 4	490
	11th to 20th	Day	13% 16% 34% 26% 11%	490
	21st to end	Day	18% 17% 28% 25% 11% 1	490
October	1st to 10th	Day	18% 19% 30% 19% 12% 1	490
	11th to 20th	Day	27% 17% 21% 21% 11% 3	490
	21st to end	Day	31% 20% 23% 16% 7% 3	423
November	1st to 10th	Day	34% 17% 28% 16% 4	264
	11th to 20th	Day	38% 19% 19% 14% 8% 2	180
	21st to end	Day	31% 18% 23% 20% 7%	180
December	1st to 10th	Day	34% 14% 20% 18% 10% 3	180
	11th to 20th	Day	39% 19% 28% 8% 5%	180
	21st to end	Day	32% 20% 26% 16% 5% 1	198
January	1st to 10th	Night	38% 14% 24% 15% 9% 1	760
	11th to 20th	Night	32% 12% 23% 21% 11% 1	760
	21st to end	Night	29% 10% 22% 27% 10% 2	836
February	1st to 10th	Night	32% 16% 22% 21% 9%	760
	11th to 20th	Night	31% 16% 20% 22% 10% 1	744
	21st to end	Night	32% 15% 25% 21% 7%	628
March	1st to 10th	Night	28% 15% 22% 23% 11% 1	760
	11th to 20th	Night	25% 16% 23% 25% 10% 1	760
	21st to end	Night	28% 16% 30% 17% 8% 1	836
April	1st to 10th	Night	26% 16% 27% 21% 8% 2	760
	11th to 20th	Night	20% 22% 25% 20% 11% 3	751
	21st to end	Night	17% 19% 31% 22% 11% 2	595
May	1st to 10th	Night	15% 14% 28% 27% 14% 2	380
	11th to 20th	Night	13% 12% 24% 31% 17% 2	374
	21st to end	Night	9% 11% 32% 28% 17% 3	411
June	1st to 10th	Night	18% 13% 25% 28% 15% 1	380
	11th to 20th	Night	11% 18% 32% 26% 12%	380
	21st to end	Night	6% 12% 31% 36% 13% 1	380
July	1st to 10th	Night	3 7% 37% 36% 16%	370
	11th to 20th	Night	3 7% 39% 37% 14% 1	368
	21st to end	Night	3 7% 29% 36% 21% 3	416
August	1st to 10th	Night	3 6% 27% 40% 22% 3	436
	11th to 20th	Night	4 5% 24% 32% 27% 9%	564
	21st to end	Night	7% 11% 30% 30% 19% 3	802
September	1st to 10th	Night	6% 8% 28% 34% 21% 4	760
	11th to 20th	Night	9% 10% 26% 26% 23% 6%	760
	21st to end	Night	11% 13% 23% 28% 23% 3	760
October	1st to 10th	Night	16% 11% 23% 31% 16% 3	760
	11th to 20th	Night	21% 12% 20% 26% 17% 4	760
	21st to end	Night	26% 14% 23% 23% 12% 3	836
November	1st to 10th	Night	30% 12% 26% 24% 7%	770
	11th to 20th	Night	35% 13% 23% 18% 10% 1	760
	21st to end	Night	23% 14% 25% 24% 12% 1	760
December	1st to 10th	Night	28% 13% 26% 22% 11% 1	760
	11th to 20th	Night	35% 11% 24% 21% 8% 1	760
	21st to end	Night	39% 15% 25% 15% 6%	836

Page generated at 2024-11-05 05:15:49. Version ac07

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