Loon Lake Road Observing Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Loon Lake Road Observing Site clear sky chart from 2005-11-06 to 2024-11-03.

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	8% 11% 4 9% 6% 5% 5% 4 6% 7% 36%	101606
	Night	7% 11% 4 9% 6% 5% 5% 4 6% 7% 35%	97423
Transparency	Day	46% 9% 13% 19% 11% 3	101362
	Night	46% 10% 15% 18% 9% 2	97312
Seeing	Day	18% 19% 28% 21% 11% 3	15369
	Night	15% 16% 28% 26% 14% 2	23755

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	10% 20% 6% 13% 7% 6% 5% 4 6% 7% 16%	2219
	11th to 20th	Day	5% 16% 5% 13% 6% 6% 5% 4 6% 8% 25%	2430
	21st to end	Day	6% 16% 5% 12% 8% 7% 7% 5% 7% 7% 19%	2794
February	1st to 10th	Day	7% 20% 5% 11% 7% 5% 6% 6% 7% 7% 19%	1599
	11th to 20th	Day	5% 18% 6% 12% 7% 6% 6% 4 6% 8% 22%	1665
	21st to end	Day	5% 18% 6% 14% 7% 7% 6% 4 7% 5% 21%	1513
March	1st to 10th	Day	5% 15% 6% 14% 7% 5% 5% 5% 6% 7% 25%	3138
	11th to 20th	Day	4 13% 4 8% 6% 5% 6% 4 7% 6% 38%	3392
	21st to end	Day	8% 18% 6% 12% 7% 5% 5% 4 7% 6% 22%	4068
April	1st to 10th	Day	8% 16% 6% 12% 7% 7% 7% 5% 6% 6% 21%	2280
	11th to 20th	Day	8% 13% 5% 10% 7% 6% 6% 5% 6% 6% 28%	2252
	21st to end	Day	8% 16% 5% 10% 6% 5% 6% 4 7% 7% 25%	2632
May	1st to 10th	Day	6% 14% 4 9% 5% 5% 5% 3 6% 7% 37%	4420
	11th to 20th	Day	8% 11% 3 9% 6% 5% 5% 5% 8% 11% 29%	4377
	21st to end	Day	15% 17% 5% 10% 6% 5% 5% 4 5% 6% 23%	4813
June	1st to 10th	Day	15% 10% 3 9% 6% 5% 5% 4 6% 6% 31%	2866
	11th to 20th	Day	16% 9% 3 8% 6% 5% 4 5% 6% 7% 30%	3040
	21st to end	Day	10% 7% 3 8% 6% 4 6% 4 6% 7% 40%	2971
July	1st to 10th	Day	5% 3 2 4 3 3 3 3 4 6% 63%	4740
	11th to 20th	Day	4 2 1 3 2 2 3 3 4 6% 71%	4613
	21st to end	Day	6% 3 2 4 3 3 3 3 5% 7% 61%	4790
August	1st to 10th	Day	3 2 1 4 3 4 4 3 5% 7% 63%	4401
	11th to 20th	Day	4 4 2 6% 4 5% 5% 5% 7% 8% 50%	4238
	21st to end	Day	9% 6% 2 6% 5% 4 5% 4 7% 8% 44%	4283
September	1st to 10th	Day	9% 6% 2 7% 4 4 4 3 4 6% 51%	2280
	11th to 20th	Day	11% 8% 2 8% 6% 5% 5% 3 4 6% 42%	2280
	21st to end	Day	12% 9% 2 8% 5% 5% 4 4 6% 7% 37%	2037
October	1st to 10th	Day	11% 11% 4 9% 4 4 4 4 5% 5% 37%	1900
	11th to 20th	Day	13% 12% 5% 9% 6% 5% 5% 4 5% 6% 31%	1878
	21st to end	Day	11% 14% 4 9% 6% 5% 5% 4 6% 6% 29%	1881
November	1st to 10th	Day	13% 16% 5% 11% 6% 7% 5% 5% 4 6% 22%	1560
	11th to 20th	Day	11% 15% 5% 8% 7% 5% 5% 5% 6% 6% 27%	1520
	21st to end	Day	8% 16% 5% 9% 7% 5% 6% 5% 7% 8% 23%	1495
December	1st to 10th	Day	7% 13% 5% 13% 8% 6% 8% 6% 6% 6% 23%	1330
	11th to 20th	Day	7% 14% 4 13% 7% 6% 7% 6% 7% 8% 22%	1588
	21st to end	Day	7% 14% 6% 13% 10% 7% 7% 6% 7% 7% 18%	2323
January	1st to 10th	Night	10% 19% 6% 14% 7% 6% 6% 5% 6% 6% 14%	4726
	11th to 20th	Night	6% 16% 6% 11% 6% 5% 5% 4 9% 6% 26%	4464
	21st to end	Night	7% 13% 5% 13% 8% 8% 7% 6% 8% 8% 19%	4862
February	1st to 10th	Night	8% 20% 6% 13% 7% 4 5% 4 6% 6% 22%	2580
	11th to 20th	Night	5% 15% 5% 12% 7% 6% 5% 5% 6% 6% 30%	2402
	21st to end	Night	5% 14% 7% 12% 9% 6% 6% 4 6% 7% 24%	1940
March	1st to 10th	Night	3 11% 5% 12% 7% 6% 6% 6% 8% 9% 28%	3736
	11th to 20th	Night	3 8% 3 6% 5% 5% 5% 5% 7% 8% 44%	3584
	21st to end	Night	6% 14% 5% 10% 7% 6% 7% 5% 6% 7% 26%	3584
April	1st to 10th	Night	5% 12% 4 10% 6% 7% 5% 5% 5% 8% 32%	1900
	11th to 20th	Night	5% 12% 4 9% 6% 6% 7% 5% 7% 7% 32%	1879
	21st to end	Night	6% 11% 4 8% 6% 6% 6% 5% 6% 9% 32%	1546
May	1st to 10th	Night	8% 11% 3 7% 5% 4 5% 4 6% 7% 41%	2540
	11th to 20th	Night	6% 9% 3 7% 5% 5% 4 5% 7% 10% 39%	2516
	21st to end	Night	8% 14% 4 10% 7% 6% 7% 5% 6% 5% 26%	2762
June	1st to 10th	Night	10% 10% 3 6% 5% 6% 5% 6% 6% 9% 34%	1305
	11th to 20th	Night	10% 7% 3 7% 6% 5% 6% 4 7% 8% 36%	1140
	21st to end	Night	5% 7% 2 6% 5% 3 5% 4 7% 10% 47%	1204
July	1st to 10th	Night	3 3 1 4 2 2 3 3 4 5% 70%	2220
	11th to 20th	Night	3 2 1 2 2 3 2 3 4 5% 74%	2343
	21st to end	Night	3 2 1 4 2 2 3 2 5% 7% 69%	2762
August	1st to 10th	Night	2 2 1 3 2 3 5% 4 6% 9% 63%	2529
	11th to 20th	Night	3 3 1 4 3 4 4 4 7% 9% 59%	2589
	21st to end	Night	9% 6% 3 7% 4 4 5% 4 6% 7% 47%	3392
September	1st to 10th	Night	6% 5% 1 4 4 3 4 4 5% 7% 57%	1900
	11th to 20th	Night	8% 6% 2 6% 4 4 5% 3 6% 8% 48%	1900
	21st to end	Night	10% 10% 3 7% 4 4 4 3 6% 9% 40%	2139
October	1st to 10th	Night	9% 9% 3 8% 5% 4 5% 4 6% 7% 40%	2280
	11th to 20th	Night	14% 11% 3 8% 5% 5% 4 4 5% 6% 36%	2301
	21st to end	Night	11% 13% 5% 9% 6% 5% 5% 3 6% 5% 33%	2717
November	1st to 10th	Night	13% 15% 4 11% 5% 5% 5% 5% 5% 7% 25%	2559
	11th to 20th	Night	9% 15% 5% 11% 7% 6% 4 5% 6% 6% 26%	2660
	21st to end	Night	9% 16% 5% 10% 6% 6% 5% 4 7% 6% 25%	2664
December	1st to 10th	Night	7% 15% 4 11% 6% 6% 6% 6% 6% 6% 28%	2850
	11th to 20th	Night	8% 19% 7% 14% 7% 6% 6% 5% 5% 7% 18%	3588
	21st to end	Night	6% 13% 5% 13% 7% 7% 7% 5% 7% 8% 21%	5360

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	65% 12% 10% 10% 3 1	2219
	11th to 20th	Day	56% 7% 16% 13% 4 5%	2454
	21st to end	Day	60% 12% 13% 10% 4	2794
February	1st to 10th	Day	61% 12% 12% 9% 6% 1	1599
	11th to 20th	Day	59% 11% 13% 10% 7% 1	1674
	21st to end	Day	63% 11% 9% 12% 5%	1513
March	1st to 10th	Day	54% 10% 11% 16% 9% 1	3138
	11th to 20th	Day	43% 10% 16% 23% 7%	3392
	21st to end	Day	59% 12% 13% 9% 8%	4068
April	1st to 10th	Day	60% 12% 13% 13% 2	2280
	11th to 20th	Day	55% 10% 11% 14% 10% 1	2252
	21st to end	Day	56% 10% 14% 13% 7%	2632
May	1st to 10th	Day	42% 11% 12% 25% 9%	4420
	11th to 20th	Day	42% 13% 19% 21% 5%	4380
	21st to end	Day	59% 10% 13% 14% 3	4814
June	1st to 10th	Day	53% 9% 12% 16% 7% 3	2866
	11th to 20th	Day	52% 11% 13% 18% 6%	3040
	21st to end	Day	42% 9% 15% 20% 12% 2	2971
July	1st to 10th	Day	24% 4 8% 20% 27% 17%	4666
	11th to 20th	Day	17% 5% 8% 22% 32% 16%	4532
	21st to end	Day	24% 3 13% 30% 21% 8%	4639
August	1st to 10th	Day	21% 5% 10% 27% 31% 6%	4384
	11th to 20th	Day	32% 4 24% 28% 10% 2	4280
	21st to end	Day	38% 5% 18% 25% 13% 1	4282
September	1st to 10th	Day	35% 6% 14% 26% 15% 4	2280
	11th to 20th	Day	43% 6% 11% 21% 15% 3	2280
	21st to end	Day	45% 8% 17% 17% 9% 3	2037
October	1st to 10th	Day	49% 8% 14% 23% 7%	1900
	11th to 20th	Day	53% 8% 12% 19% 6% 1	1878
	21st to end	Day	54% 10% 13% 18% 5%	1881
November	1st to 10th	Day	63% 11% 11% 10% 5%	1560
	11th to 20th	Day	58% 9% 13% 14% 5% 1	1520
	21st to end	Day	56% 10% 13% 14% 5% 2	1495
December	1st to 10th	Day	57% 14% 14% 11% 4	1330
	11th to 20th	Day	57% 13% 16% 10% 4	1589
	21st to end	Day	60% 13% 12% 12% 2	2323
January	1st to 10th	Night	65% 12% 12% 8% 2	4726
	11th to 20th	Night	55% 8% 14% 12% 7% 5%	4502
	21st to end	Night	58% 15% 13% 9% 4	4862
February	1st to 10th	Night	62% 9% 12% 12% 5% 1	2580
	11th to 20th	Night	54% 10% 13% 14% 7% 2	2404
	21st to end	Night	59% 9% 11% 14% 6%	1940
March	1st to 10th	Night	44% 13% 14% 18% 11%	3736
	11th to 20th	Night	33% 11% 19% 29% 8%	3585
	21st to end	Night	51% 12% 15% 15% 7%	3584
April	1st to 10th	Night	48% 12% 20% 16% 4	1900
	11th to 20th	Night	47% 11% 15% 18% 8%	1879
	21st to end	Night	46% 10% 18% 18% 7%	1546
May	1st to 10th	Night	38% 10% 15% 30% 7%	2540
	11th to 20th	Night	35% 13% 21% 26% 5%	2516
	21st to end	Night	52% 14% 16% 15% 4	2762
June	1st to 10th	Night	44% 10% 16% 20% 7% 3	1305
	11th to 20th	Night	42% 12% 19% 18% 8%	1140
	21st to end	Night	31% 11% 23% 24% 11% 1	1204
July	1st to 10th	Night	17% 6% 10% 31% 21% 16%	2185
	11th to 20th	Night	15% 3 11% 26% 36% 10%	2301
	21st to end	Night	17% 3 17% 31% 19% 14%	2674
August	1st to 10th	Night	19% 5% 13% 26% 34% 4	2521
	11th to 20th	Night	22% 5% 29% 32% 10% 3	2613
	21st to end	Night	36% 6% 20% 25% 12% 2	3392
September	1st to 10th	Night	26% 8% 16% 31% 15% 4	1900
	11th to 20th	Night	33% 10% 15% 21% 18% 5%	1900
	21st to end	Night	42% 9% 18% 20% 10% 2	2139
October	1st to 10th	Night	42% 8% 16% 24% 9% 1	2280
	11th to 20th	Night	50% 7% 12% 21% 9% 1	2301
	21st to end	Night	52% 7% 13% 20% 7%	2717
November	1st to 10th	Night	59% 10% 13% 12% 6% 1	2559
	11th to 20th	Night	57% 10% 14% 12% 5% 1	2660
	21st to end	Night	56% 12% 13% 11% 6% 2	2664
December	1st to 10th	Night	55% 12% 13% 16% 4 1	2850
	11th to 20th	Night	64% 11% 12% 10% 3	3585
	21st to end	Night	55% 14% 14% 13% 4	5360

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	18% 26% 28% 12% 11% 5%	180
	11th to 20th	Day	14% 19% 32% 21% 12% 2	180
	21st to end	Day	14% 25% 32% 21% 9%	198
February	1st to 10th	Day	28% 24% 27% 16% 4 1	259
	11th to 20th	Day	18% 23% 34% 17% 6% 2	365
	21st to end	Day	22% 23% 34% 15% 6% 1	355
March	1st to 10th	Day	22% 24% 27% 18% 8% 1	460
	11th to 20th	Day	19% 25% 25% 17% 10% 3	460
	21st to end	Day	21% 28% 22% 17% 10% 1	506
April	1st to 10th	Day	25% 25% 28% 16% 5% 1	460
	11th to 20th	Day	20% 25% 23% 19% 9% 3	452
	21st to end	Day	23% 24% 25% 17% 8% 2	460
May	1st to 10th	Day	17% 19% 33% 20% 8% 2	463
	11th to 20th	Day	18% 16% 24% 27% 12% 2	488
	21st to end	Day	22% 18% 25% 21% 11% 3	529
June	1st to 10th	Day	21% 21% 30% 19% 8% 1	696
	11th to 20th	Day	22% 20% 29% 18% 10% 2	870
	21st to end	Day	16% 15% 29% 23% 14% 3	801
July	1st to 10th	Day	11% 15% 33% 27% 13% 1	671
	11th to 20th	Day	9% 16% 31% 28% 14% 2	593
	21st to end	Day	8% 11% 31% 31% 16% 3	531
August	1st to 10th	Day	7% 11% 27% 31% 18% 6%	487
	11th to 20th	Day	7% 10% 30% 29% 18% 6%	477
	21st to end	Day	12% 15% 31% 25% 12% 5%	539
September	1st to 10th	Day	13% 16% 29% 22% 16% 4	490
	11th to 20th	Day	16% 15% 28% 24% 13% 3	490
	21st to end	Day	22% 19% 27% 19% 10% 3	490
October	1st to 10th	Day	23% 17% 25% 17% 14% 4	490
	11th to 20th	Day	25% 20% 22% 16% 13% 2	468
	21st to end	Day	25% 18% 28% 18% 9% 2	330
November	1st to 10th	Day	24% 22% 28% 20% 5% 1	213
	11th to 20th	Day	25% 21% 24% 12% 14% 3	180
	21st to end	Day	21% 21% 28% 16% 9% 5%	180
December	1st to 10th	Day	23% 12% 23% 23% 13% 6%	180
	11th to 20th	Day	18% 24% 27% 18% 8% 4	180
	21st to end	Day	18% 16% 35% 22% 6% 3	198
January	1st to 10th	Night	24% 18% 30% 17% 9% 1	850
	11th to 20th	Night	16% 18% 30% 26% 9% 1	781
	21st to end	Night	15% 16% 31% 25% 11% 2	836
February	1st to 10th	Night	21% 17% 27% 23% 8% 3	760
	11th to 20th	Night	12% 17% 30% 27% 11% 2	744
	21st to end	Night	14% 18% 26% 25% 15% 1	628
March	1st to 10th	Night	14% 21% 24% 24% 14% 2	760
	11th to 20th	Night	13% 20% 33% 22% 10% 2	760
	21st to end	Night	15% 19% 28% 24% 12% 2	836
April	1st to 10th	Night	13% 19% 27% 28% 12% 2	760
	11th to 20th	Night	11% 18% 30% 26% 13% 1	751
	21st to end	Night	12% 16% 30% 30% 11% 1	406
May	1st to 10th	Night	14% 11% 29% 30% 15% 2	380
	11th to 20th	Night	9% 8% 28% 35% 18% 1	374
	21st to end	Night	17% 9% 27% 30% 16% 2	411
June	1st to 10th	Night	13% 14% 32% 28% 11% 1	380
	11th to 20th	Night	14% 14% 31% 28% 12%	380
	21st to end	Night	7% 11% 33% 29% 19% 2	380
July	1st to 10th	Night	7% 8% 25% 38% 21% 2	370
	11th to 20th	Night	6% 10% 29% 36% 18% 1	368
	21st to end	Night	4 7% 28% 37% 21% 2	416
August	1st to 10th	Night	4 5% 21% 39% 27% 4	378
	11th to 20th	Night	5% 4 25% 32% 28% 5%	429
	21st to end	Night	10% 8% 25% 32% 22% 2	769
September	1st to 10th	Night	9% 10% 27% 28% 22% 4	760
	11th to 20th	Night	12% 8% 23% 24% 26% 7%	760
	21st to end	Night	18% 14% 26% 22% 18% 3	760
October	1st to 10th	Night	15% 11% 26% 26% 18% 3	760
	11th to 20th	Night	21% 16% 23% 23% 15% 2	760
	21st to end	Night	20% 20% 25% 22% 11% 3	836
November	1st to 10th	Night	23% 17% 30% 23% 6% 1	748
	11th to 20th	Night	21% 21% 29% 19% 9% 1	760
	21st to end	Night	18% 21% 26% 21% 11% 2	764
December	1st to 10th	Night	16% 15% 28% 27% 11% 2	950
	11th to 20th	Night	18% 21% 31% 22% 7% 1	974
	21st to end	Night	17% 21% 32% 23% 7%	1016

Page generated at 2024-10-31 00:39:25. Version ac07

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