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 2024-03-23.

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% 11% 4 8% 7% 4 6% 5% 6% 7% 33%	78253
	Night	8% 11% 5% 8% 7% 4 6% 6% 6% 7% 32%	81550
Transparency	Day	49% 10% 13% 18% 9% 2	77967
	Night	49% 10% 15% 17% 8% 1	81415
Seeing	Day	18% 19% 28% 21% 11% 3	14422
	Night	15% 16% 28% 26% 14% 2	23099

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% 19% 7% 12% 8% 5% 6% 5% 5% 7% 16%	2219
	11th to 20th	Day	5% 15% 6% 11% 8% 4 6% 5% 6% 8% 25%	2430
	21st to end	Day	7% 15% 6% 10% 10% 5% 7% 6% 7% 8% 19%	2794
February	1st to 10th	Day	8% 18% 6% 10% 9% 4 6% 7% 7% 8% 19%	1599
	11th to 20th	Day	5% 17% 7% 10% 9% 4 6% 5% 7% 8% 22%	1665
	21st to end	Day	6% 16% 7% 13% 8% 5% 6% 6% 7% 5% 21%	1513
March	1st to 10th	Day	5% 15% 7% 12% 8% 4 5% 6% 6% 7% 24%	1900
	11th to 20th	Day	7% 15% 6% 9% 8% 4 8% 6% 6% 6% 25%	2028
	21st to end	Day	8% 16% 7% 11% 7% 5% 6% 6% 8% 7% 19%	2341
April	1st to 10th	Day	9% 15% 6% 10% 9% 5% 7% 6% 6% 7% 21%	2160
	11th to 20th	Day	9% 12% 6% 9% 8% 4 7% 6% 6% 7% 26%	2132
	21st to end	Day	9% 15% 5% 9% 7% 4 5% 6% 6% 8% 26%	2492
May	1st to 10th	Day	9% 13% 4 8% 7% 4 5% 5% 6% 7% 32%	2520
	11th to 20th	Day	10% 10% 4 7% 7% 4 6% 6% 7% 8% 31%	2477
	21st to end	Day	15% 10% 4 8% 7% 3 6% 5% 6% 7% 30%	2723
June	1st to 10th	Day	16% 9% 4 8% 7% 3 5% 5% 5% 6% 31%	2715
	11th to 20th	Day	16% 8% 4 8% 7% 4 5% 6% 6% 7% 30%	2880
	21st to end	Day	10% 6% 3 7% 7% 3 6% 5% 6% 8% 41%	2815
July	1st to 10th	Day	7% 4 2 5% 6% 3 4 5% 6% 8% 50%	2700
	11th to 20th	Day	6% 3 2 5% 4 3 4 5% 5% 7% 56%	2629
	21st to end	Day	4 2 1 2 3 3 3 3 5% 7% 66%	2741
August	1st to 10th	Day	6% 4 1 4 4 3 5% 4 5% 7% 58%	2507
	11th to 20th	Day	4 4 2 4 4 3 4 5% 5% 6% 58%	2422
	21st to end	Day	9% 6% 2 5% 5% 3 5% 6% 7% 8% 44%	2440
September	1st to 10th	Day	9% 6% 2 6% 5% 3 4 4 4 7% 50%	2160
	11th to 20th	Day	11% 8% 2 7% 7% 4 5% 5% 4 6% 41%	2160
	21st to end	Day	12% 9% 2 7% 6% 3 5% 5% 6% 8% 38%	1931
October	1st to 10th	Day	11% 11% 5% 8% 5% 3 4 5% 5% 5% 38%	1800
	11th to 20th	Day	12% 12% 5% 8% 7% 4 5% 5% 5% 6% 31%	1780
	21st to end	Day	12% 13% 5% 7% 8% 4 5% 5% 6% 7% 29%	1782
November	1st to 10th	Day	14% 14% 6% 9% 7% 5% 6% 6% 5% 6% 22%	1542
	11th to 20th	Day	11% 14% 6% 7% 8% 3 6% 6% 6% 7% 27%	1520
	21st to end	Day	8% 15% 6% 8% 8% 4 6% 6% 7% 8% 24%	1495
December	1st to 10th	Day	7% 11% 6% 12% 10% 4 8% 8% 6% 6% 24%	1330
	11th to 20th	Day	7% 13% 5% 11% 8% 4 7% 7% 7% 8% 22%	1588
	21st to end	Day	7% 13% 6% 11% 12% 5% 7% 7% 6% 7% 18%	2323
January	1st to 10th	Night	10% 18% 7% 12% 9% 5% 6% 6% 6% 7% 14%	4726
	11th to 20th	Night	7% 15% 6% 10% 7% 3 5% 5% 8% 6% 26%	4464
	21st to end	Night	7% 12% 6% 11% 10% 5% 8% 7% 8% 8% 19%	4862
February	1st to 10th	Night	9% 18% 7% 11% 8% 3 5% 5% 6% 6% 22%	2580
	11th to 20th	Night	5% 13% 6% 10% 8% 4 6% 6% 6% 6% 30%	2402
	21st to end	Night	6% 12% 8% 11% 10% 4 7% 5% 6% 7% 24%	1940
March	1st to 10th	Night	5% 13% 6% 10% 7% 4 6% 6% 7% 7% 29%	2280
	11th to 20th	Night	5% 11% 5% 7% 7% 5% 6% 6% 8% 8% 32%	2148
	21st to end	Night	6% 14% 6% 9% 8% 4 6% 7% 6% 8% 27%	2059
April	1st to 10th	Night	5% 10% 5% 9% 7% 5% 6% 6% 5% 8% 32%	1800
	11th to 20th	Night	6% 11% 4 9% 7% 4 8% 6% 6% 7% 32%	1779
	21st to end	Night	6% 10% 4 6% 7% 4 6% 6% 6% 10% 34%	1466
May	1st to 10th	Night	9% 10% 3 6% 6% 3 5% 5% 6% 8% 38%	1440
	11th to 20th	Night	7% 6% 3 5% 7% 4 6% 7% 8% 9% 38%	1416
	21st to end	Night	11% 10% 3 6% 6% 3 5% 5% 6% 7% 39%	1552
June	1st to 10th	Night	11% 8% 3 5% 6% 4 5% 7% 6% 9% 35%	1238
	11th to 20th	Night	10% 7% 3 6% 7% 4 6% 6% 7% 9% 36%	1080
	21st to end	Night	5% 6% 3 5% 5% 2 5% 5% 7% 9% 49%	1140
July	1st to 10th	Night	6% 4 2 5% 4 2 5% 6% 5% 7% 55%	1260
	11th to 20th	Night	5% 3 1 3 3 3 5% 5% 6% 7% 60%	1327
	21st to end	Night	3 2 1 3 2 1 2 3 5% 7% 71%	1576
August	1st to 10th	Night	3 2 1 3 3 1 4 5% 5% 7% 65%	1432
	11th to 20th	Night	3 4 1 3 3 2 4 3 4 7% 64%	1474
	21st to end	Night	6% 4 2 4 4 3 5% 6% 6% 8% 51%	1916
September	1st to 10th	Night	6% 5% 1 3 5% 3 4 5% 6% 7% 56%	1800
	11th to 20th	Night	9% 6% 2 4 5% 3 6% 5% 6% 8% 48%	1800
	21st to end	Night	11% 9% 3 6% 5% 3 5% 4 6% 9% 40%	2025
October	1st to 10th	Night	9% 9% 3 7% 6% 3 5% 6% 6% 7% 40%	2160
	11th to 20th	Night	13% 11% 3 7% 7% 4 4 5% 4 6% 36%	2179
	21st to end	Night	11% 12% 5% 7% 7% 4 5% 5% 6% 5% 33%	2574
November	1st to 10th	Night	14% 14% 5% 9% 7% 4 5% 6% 5% 7% 25%	2533
	11th to 20th	Night	9% 14% 6% 10% 8% 4 6% 5% 6% 6% 26%	2660
	21st to end	Night	9% 14% 6% 9% 7% 5% 5% 6% 6% 6% 25%	2664
December	1st to 10th	Night	7% 14% 5% 9% 7% 5% 6% 7% 6% 6% 28%	2850
	11th to 20th	Night	8% 18% 7% 12% 8% 4 6% 6% 5% 7% 18%	3588
	21st to end	Night	6% 13% 6% 11% 9% 5% 7% 6% 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	57% 9% 13% 14% 6% 1	1900
	11th to 20th	Day	58% 10% 12% 15% 5%	2028
	21st to end	Day	62% 11% 14% 11% 3	2341
April	1st to 10th	Day	60% 12% 13% 13% 2	2160
	11th to 20th	Day	57% 10% 11% 13% 8% 1	2132
	21st to end	Day	56% 10% 14% 13% 7%	2492
May	1st to 10th	Day	51% 9% 15% 16% 8% 1	2520
	11th to 20th	Day	50% 9% 15% 20% 6%	2480
	21st to end	Day	53% 9% 13% 19% 5% 1	2724
June	1st to 10th	Day	54% 8% 12% 16% 7% 4	2715
	11th to 20th	Day	52% 11% 13% 17% 6%	2880
	21st to end	Day	41% 10% 16% 20% 11% 2	2815
July	1st to 10th	Day	33% 8% 13% 25% 17% 5%	2626
	11th to 20th	Day	27% 8% 15% 28% 19% 4	2548
	21st to end	Day	19% 6% 11% 32% 26% 6%	2589
August	1st to 10th	Day	26% 8% 16% 25% 20% 6%	2490
	11th to 20th	Day	25% 8% 17% 28% 18% 4	2422
	21st to end	Day	34% 9% 14% 28% 12% 2	2440
September	1st to 10th	Day	36% 6% 14% 26% 14% 3	2160
	11th to 20th	Day	44% 6% 11% 20% 15% 3	2160
	21st to end	Day	45% 8% 16% 18% 10% 3	1931
October	1st to 10th	Day	48% 8% 13% 23% 7%	1800
	11th to 20th	Day	53% 9% 13% 19% 6% 1	1780
	21st to end	Day	53% 11% 13% 18% 5%	1782
November	1st to 10th	Day	63% 11% 11% 10% 5%	1542
	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	52% 11% 13% 15% 9% 1	2280
	11th to 20th	Night	45% 12% 17% 20% 6%	2149
	21st to end	Night	54% 11% 17% 14% 4	2059
April	1st to 10th	Night	47% 12% 21% 17% 4	1800
	11th to 20th	Night	48% 11% 16% 17% 8%	1779
	21st to end	Night	46% 9% 18% 19% 7%	1466
May	1st to 10th	Night	41% 10% 21% 20% 8%	1440
	11th to 20th	Night	37% 13% 19% 22% 8%	1416
	21st to end	Night	44% 9% 17% 23% 6%	1552
June	1st to 10th	Night	44% 10% 16% 20% 7% 3	1238
	11th to 20th	Night	42% 13% 20% 18% 7%	1080
	21st to end	Night	30% 12% 24% 23% 10% 2	1140
July	1st to 10th	Night	28% 10% 14% 28% 16% 5%	1225
	11th to 20th	Night	22% 6% 19% 33% 18% 3	1285
	21st to end	Night	13% 5% 18% 30% 26% 8%	1488
August	1st to 10th	Night	18% 8% 18% 28% 21% 6%	1424
	11th to 20th	Night	19% 8% 21% 28% 18% 5%	1474
	21st to end	Night	29% 10% 17% 28% 14% 3	1916
September	1st to 10th	Night	27% 8% 16% 31% 15% 3	1800
	11th to 20th	Night	32% 10% 14% 20% 18% 5%	1800
	21st to end	Night	41% 9% 17% 20% 10% 3	2025
October	1st to 10th	Night	42% 8% 16% 24% 9% 1	2160
	11th to 20th	Night	50% 7% 12% 21% 9% 1	2179
	21st to end	Night	52% 8% 13% 20% 7%	2574
November	1st to 10th	Night	59% 10% 13% 11% 6% 1	2533
	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% 24% 18% 10% 3	460
	21st to end	Day	23% 28% 22% 17% 9% 1	471
April	1st to 10th	Day	23% 25% 28% 15% 6% 1	420
	11th to 20th	Day	20% 27% 23% 18% 9% 3	412
	21st to end	Day	24% 24% 25% 16% 8% 3	420
May	1st to 10th	Day	17% 20% 34% 20% 7% 2	423
	11th to 20th	Day	17% 15% 24% 28% 13% 3	448
	21st to end	Day	22% 17% 26% 21% 12% 3	485
June	1st to 10th	Day	20% 22% 30% 18% 9% 1	645
	11th to 20th	Day	21% 19% 30% 19% 10% 2	810
	21st to end	Day	15% 15% 29% 23% 15% 3	745
July	1st to 10th	Day	11% 15% 33% 27% 13% 2	621
	11th to 20th	Day	10% 18% 31% 27% 13% 2	547
	21st to end	Day	7% 10% 31% 32% 17% 3	487
August	1st to 10th	Day	8% 11% 27% 30% 18% 6%	447
	11th to 20th	Day	7% 11% 32% 27% 18% 6%	437
	21st to end	Day	12% 15% 32% 25% 12% 5%	495
September	1st to 10th	Day	14% 17% 30% 22% 14% 3	450
	11th to 20th	Day	17% 15% 28% 24% 13% 3	450
	21st to end	Day	20% 19% 27% 20% 11% 4	450
October	1st to 10th	Day	22% 16% 26% 17% 15% 5%	450
	11th to 20th	Day	23% 22% 23% 17% 13% 2	430
	21st to end	Day	26% 18% 26% 18% 9% 2	297
November	1st to 10th	Day	24% 22% 28% 20% 5% 1	207
	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	16% 19% 28% 24% 13% 2	800
April	1st to 10th	Night	13% 17% 27% 29% 13% 2	720
	11th to 20th	Night	12% 17% 30% 26% 13% 2	711
	21st to end	Night	12% 16% 30% 30% 12% 2	386
May	1st to 10th	Night	14% 11% 29% 30% 14% 2	360
	11th to 20th	Night	9% 8% 26% 36% 19% 1	354
	21st to end	Night	17% 8% 26% 31% 17% 2	389
June	1st to 10th	Night	13% 14% 32% 29% 12% 1	360
	11th to 20th	Night	14% 14% 32% 28% 11%	360
	21st to end	Night	7% 11% 34% 28% 19% 2	360
July	1st to 10th	Night	8% 8% 24% 38% 21% 2	350
	11th to 20th	Night	7% 10% 29% 35% 18% 1	348
	21st to end	Night	3 7% 28% 37% 22% 3	394
August	1st to 10th	Night	4 5% 21% 38% 28% 4	358
	11th to 20th	Night	5% 4 25% 31% 28% 6%	406
	21st to end	Night	9% 9% 25% 32% 22% 3	728
September	1st to 10th	Night	9% 10% 27% 27% 22% 4	720
	11th to 20th	Night	11% 8% 23% 24% 26% 7%	720
	21st to end	Night	17% 14% 25% 23% 19% 3	720
October	1st to 10th	Night	15% 11% 26% 27% 19% 3	720
	11th to 20th	Night	20% 16% 23% 23% 15% 3	720
	21st to end	Night	20% 20% 25% 21% 11% 3	792
November	1st to 10th	Night	23% 18% 30% 23% 6% 1	740
	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 2024-03-19 20:31:05. Version ac07

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