AllSky Camera - 108 Mile Ranch
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the AllSky Camera - 108 Mile Ranch clear sky chart from 2005-11-06 to 2024-11-01.

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% 10% 4 9% 6% 5% 5% 5% 6% 8% 34%	101698
	Night	8% 12% 4 10% 7% 6% 6% 5% 6% 7% 29%	97299
Transparency	Day	47% 5% 14% 22% 10% 2	101445
	Night	53% 5% 14% 19% 8% 1	97198
Seeing	Day	15% 14% 25% 26% 16% 5%	15964
	Night	16% 12% 25% 28% 16% 2	24038

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	7% 19% 6% 17% 7% 6% 6% 5% 7% 6% 14%	2219
	11th to 20th	Day	9% 14% 5% 11% 5% 5% 5% 5% 9% 8% 24%	2199
	21st to end	Day	8% 16% 5% 13% 9% 6% 6% 5% 6% 7% 19%	2676
February	1st to 10th	Day	9% 20% 6% 13% 7% 5% 4 4 5% 5% 23%	1577
	11th to 20th	Day	7% 14% 5% 11% 7% 6% 6% 4 6% 7% 27%	1665
	21st to end	Day	5% 14% 5% 13% 9% 5% 6% 4 6% 6% 25%	1456
March	1st to 10th	Day	3 11% 5% 12% 8% 7% 7% 5% 7% 8% 27%	3138
	11th to 20th	Day	3 10% 4 10% 7% 6% 6% 5% 7% 10% 31%	3445
	21st to end	Day	4 11% 4 11% 8% 6% 6% 5% 7% 8% 30%	4033
April	1st to 10th	Day	6% 15% 6% 11% 9% 6% 7% 4 7% 7% 22%	2280
	11th to 20th	Day	9% 14% 5% 12% 7% 6% 6% 4 6% 7% 24%	2320
	21st to end	Day	8% 11% 4 10% 7% 8% 6% 5% 7% 7% 26%	2650
May	1st to 10th	Day	7% 10% 3 9% 6% 5% 5% 5% 6% 9% 35%	4420
	11th to 20th	Day	7% 10% 4 10% 7% 6% 6% 5% 8% 9% 29%	4377
	21st to end	Day	14% 13% 4 11% 7% 6% 6% 5% 6% 7% 22%	5117
June	1st to 10th	Day	16% 11% 4 9% 6% 5% 6% 4 6% 6% 26%	3040
	11th to 20th	Day	14% 10% 4 10% 7% 6% 6% 5% 7% 8% 23%	3040
	21st to end	Day	10% 8% 3 8% 6% 6% 6% 5% 6% 7% 33%	3040
July	1st to 10th	Day	5% 5% 1 4 3 4 4 4 5% 6% 58%	4904
	11th to 20th	Day	4 4 1 4 3 3 4 3 5% 7% 62%	4740
	21st to end	Day	7% 6% 2 5% 4 4 4 4 7% 9% 48%	4959
August	1st to 10th	Day	5% 4 2 5% 4 3 4 4 6% 9% 55%	4401
	11th to 20th	Day	4 3 2 5% 4 5% 6% 5% 8% 11% 45%	4252
	21st to end	Day	9% 6% 2 7% 5% 5% 5% 4 7% 10% 41%	4381
September	1st to 10th	Day	9% 6% 2 6% 4 3 4 3 6% 7% 49%	2280
	11th to 20th	Day	12% 7% 3 7% 5% 6% 4 4 5% 8% 41%	2280
	21st to end	Day	13% 9% 3 8% 5% 5% 5% 5% 6% 7% 34%	2023
October	1st to 10th	Day	12% 12% 3 8% 5% 4 4 4 6% 6% 37%	1900
	11th to 20th	Day	15% 8% 3 8% 5% 5% 5% 4 5% 7% 34%	1878
	21st to end	Day	13% 13% 4 8% 5% 5% 5% 4 6% 6% 29%	1848
November	1st to 10th	Day	12% 16% 5% 12% 6% 5% 6% 5% 6% 6% 22%	1488
	11th to 20th	Day	11% 12% 4 11% 7% 6% 6% 5% 6% 8% 23%	1520
	21st to end	Day	8% 19% 4 11% 8% 6% 7% 5% 7% 8% 18%	1387
December	1st to 10th	Day	8% 15% 5% 11% 8% 8% 6% 7% 7% 6% 19%	1224
	11th to 20th	Day	5% 16% 5% 15% 8% 8% 7% 6% 6% 8% 16%	1442
	21st to end	Day	6% 16% 5% 10% 8% 6% 6% 5% 7% 8% 22%	2099
January	1st to 10th	Night	9% 17% 6% 17% 8% 6% 6% 4 6% 6% 15%	4744
	11th to 20th	Night	6% 15% 6% 13% 7% 5% 5% 5% 7% 7% 23%	4699
	21st to end	Night	8% 15% 5% 13% 8% 7% 7% 5% 7% 7% 18%	4978
February	1st to 10th	Night	9% 19% 8% 13% 7% 6% 4 3 5% 6% 21%	2600
	11th to 20th	Night	7% 14% 4 11% 7% 6% 5% 4 6% 6% 29%	2402
	21st to end	Night	5% 14% 6% 11% 7% 6% 6% 4 6% 7% 28%	1997
March	1st to 10th	Night	3 15% 6% 11% 6% 6% 5% 5% 8% 11% 25%	3736
	11th to 20th	Night	3 10% 3 8% 6% 6% 6% 7% 9% 11% 32%	3533
	21st to end	Night	4 12% 4 11% 6% 7% 7% 5% 7% 7% 30%	3619
April	1st to 10th	Night	5% 12% 5% 11% 8% 7% 6% 5% 6% 7% 28%	1900
	11th to 20th	Night	6% 13% 4 10% 7% 5% 6% 5% 7% 8% 29%	1806
	21st to end	Night	7% 11% 5% 10% 7% 6% 7% 4 6% 8% 30%	1530
May	1st to 10th	Night	7% 12% 4 10% 7% 5% 5% 4 6% 6% 35%	2540
	11th to 20th	Night	11% 11% 4 11% 7% 6% 5% 5% 5% 7% 29%	2516
	21st to end	Night	17% 15% 4 10% 6% 5% 5% 4 7% 6% 20%	2454
June	1st to 10th	Night	15% 10% 3 8% 7% 5% 6% 4 7% 8% 26%	1140
	11th to 20th	Night	16% 11% 4 9% 8% 5% 6% 5% 7% 7% 21%	1140
	21st to end	Night	10% 9% 3 9% 8% 7% 6% 4 6% 6% 32%	1140
July	1st to 10th	Night	7% 5% 2 5% 5% 4 5% 4 5% 7% 51%	2052
	11th to 20th	Night	4 4 2 5% 5% 4 4 5% 7% 7% 54%	2220
	21st to end	Night	8% 7% 3 7% 5% 5% 6% 5% 6% 7% 40%	2593
August	1st to 10th	Night	5% 4 2 8% 5% 5% 6% 4 5% 7% 50%	2529
	11th to 20th	Night	6% 6% 3 6% 5% 6% 6% 4 8% 10% 40%	2561
	21st to end	Night	9% 8% 3 9% 5% 5% 5% 4 8% 8% 37%	3291
September	1st to 10th	Night	9% 5% 2 6% 5% 5% 4 4 7% 7% 47%	1900
	11th to 20th	Night	9% 6% 2 6% 4 5% 5% 4 7% 8% 42%	1900
	21st to end	Night	12% 9% 3 7% 4 4 5% 5% 6% 7% 38%	2153
October	1st to 10th	Night	12% 10% 4 9% 4 5% 5% 4 5% 7% 36%	2280
	11th to 20th	Night	11% 11% 3 9% 7% 6% 5% 4 6% 8% 30%	2301
	21st to end	Night	13% 11% 4 8% 5% 4 6% 4 6% 8% 30%	2747
November	1st to 10th	Night	13% 14% 4 11% 6% 6% 6% 4 7% 7% 21%	2596
	11th to 20th	Night	9% 14% 5% 11% 8% 5% 5% 5% 6% 7% 25%	2660
	21st to end	Night	8% 18% 5% 11% 8% 7% 5% 4 7% 7% 20%	2772
December	1st to 10th	Night	9% 15% 5% 12% 7% 6% 7% 5% 6% 6% 22%	2954
	11th to 20th	Night	8% 19% 8% 14% 9% 6% 6% 5% 6% 6% 14%	3750
	21st to end	Night	6% 14% 5% 12% 9% 7% 7% 5% 7% 7% 21%	5566

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% 5% 13% 12% 2	2219
	11th to 20th	Day	55% 5% 20% 8% 4 7%	2220
	21st to end	Day	62% 6% 16% 13% 2	2676
February	1st to 10th	Day	65% 3 11% 12% 8%	1577
	11th to 20th	Day	55% 5% 16% 15% 9%	1674
	21st to end	Day	57% 6% 14% 17% 6%	1456
March	1st to 10th	Day	54% 6% 9% 20% 11%	3138
	11th to 20th	Day	46% 3 18% 27% 5%	3445
	21st to end	Day	51% 5% 13% 21% 10%	4033
April	1st to 10th	Day	58% 7% 11% 16% 7%	2280
	11th to 20th	Day	58% 5% 10% 17% 9% 1	2320
	21st to end	Day	55% 5% 10% 19% 10% 1	2650
May	1st to 10th	Day	45% 4 11% 27% 13% 1	4420
	11th to 20th	Day	50% 4 12% 26% 8%	4380
	21st to end	Day	61% 4 11% 18% 6%	5118
June	1st to 10th	Day	56% 6% 9% 15% 11% 3	3040
	11th to 20th	Day	58% 6% 13% 17% 6%	3040
	21st to end	Day	48% 5% 16% 20% 10% 2	3040
July	1st to 10th	Day	26% 4 10% 25% 23% 11%	4829
	11th to 20th	Day	22% 4 11% 31% 25% 7%	4659
	21st to end	Day	31% 5% 17% 27% 14% 6%	4802
August	1st to 10th	Day	27% 4 12% 36% 21% 1	4384
	11th to 20th	Day	30% 8% 22% 30% 9% 1	4294
	21st to end	Day	38% 6% 27% 22% 5% 1	4380
September	1st to 10th	Day	35% 4 20% 28% 10% 3	2280
	11th to 20th	Day	43% 4 13% 27% 10% 2	2280
	21st to end	Day	49% 5% 15% 19% 10% 1	2023
October	1st to 10th	Day	48% 5% 20% 23% 4	1900
	11th to 20th	Day	49% 3 18% 23% 6%	1878
	21st to end	Day	54% 5% 17% 19% 4	1848
November	1st to 10th	Day	60% 6% 13% 15% 6%	1488
	11th to 20th	Day	59% 6% 15% 15% 4	1520
	21st to end	Day	63% 6% 13% 12% 5%	1387
December	1st to 10th	Day	62% 8% 14% 14% 2	1224
	11th to 20th	Day	66% 7% 16% 9% 3	1444
	21st to end	Day	59% 5% 16% 15% 5%	2099
January	1st to 10th	Night	69% 3 12% 13% 3	4744
	11th to 20th	Night	58% 5% 15% 11% 6% 5%	4740
	21st to end	Night	62% 7% 17% 12% 3	4978
February	1st to 10th	Night	65% 4 11% 13% 7% 1	2600
	11th to 20th	Night	56% 5% 13% 18% 7% 1	2404
	21st to end	Night	54% 5% 14% 19% 7% 1	1997
March	1st to 10th	Night	51% 5% 10% 20% 13%	3736
	11th to 20th	Night	41% 4 17% 30% 8%	3534
	21st to end	Night	51% 4 15% 16% 13%	3619
April	1st to 10th	Night	53% 6% 14% 19% 7%	1900
	11th to 20th	Night	52% 6% 10% 21% 11%	1806
	21st to end	Night	52% 5% 10% 21% 11% 1	1530
May	1st to 10th	Night	48% 4 10% 24% 12% 2	2540
	11th to 20th	Night	54% 4 9% 25% 8%	2516
	21st to end	Night	62% 4 13% 16% 4	2454
June	1st to 10th	Night	53% 7% 8% 20% 9% 3	1140
	11th to 20th	Night	60% 6% 13% 14% 6%	1140
	21st to end	Night	52% 5% 13% 20% 8% 2	1140
July	1st to 10th	Night	33% 5% 8% 20% 25% 9%	2018
	11th to 20th	Night	27% 5% 9% 30% 25% 4	2178
	21st to end	Night	41% 5% 13% 22% 11% 8%	2511
August	1st to 10th	Night	33% 4 10% 34% 19% 1	2521
	11th to 20th	Night	37% 6% 20% 26% 9% 1	2585
	21st to end	Night	43% 5% 26% 20% 6% 1	3291
September	1st to 10th	Night	34% 6% 15% 30% 13% 2	1900
	11th to 20th	Night	37% 5% 16% 26% 12% 3	1900
	21st to end	Night	44% 6% 16% 21% 11% 1	2153
October	1st to 10th	Night	48% 3 16% 25% 7%	2280
	11th to 20th	Night	51% 5% 14% 24% 6%	2301
	21st to end	Night	51% 5% 17% 21% 6%	2747
November	1st to 10th	Night	60% 7% 14% 14% 5%	2596
	11th to 20th	Night	57% 7% 15% 13% 7% 1	2660
	21st to end	Night	63% 5% 14% 12% 6%	2772
December	1st to 10th	Night	60% 5% 16% 13% 5%	2954
	11th to 20th	Night	69% 7% 12% 9% 3	3747
	21st to end	Night	62% 5% 15% 13% 5%	5566

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% 20% 36% 16% 7% 3	180
	11th to 20th	Day	12% 23% 32% 19% 12% 1	180
	21st to end	Day	23% 16% 30% 22% 9% 1	198
February	1st to 10th	Day	22% 21% 32% 18% 6% 2	237
	11th to 20th	Day	15% 15% 31% 28% 11% 1	365
	21st to end	Day	11% 21% 32% 22% 12% 3	328
March	1st to 10th	Day	17% 21% 27% 20% 14% 2	460
	11th to 20th	Day	14% 22% 28% 21% 12% 3	460
	21st to end	Day	16% 22% 26% 20% 12% 4	506
April	1st to 10th	Day	18% 22% 26% 23% 9% 2	460
	11th to 20th	Day	17% 24% 22% 21% 11% 6%	452
	21st to end	Day	15% 15% 28% 24% 13% 4	460
May	1st to 10th	Day	13% 17% 29% 24% 13% 4	463
	11th to 20th	Day	15% 11% 24% 27% 19% 5%	488
	21st to end	Day	18% 11% 21% 29% 16% 4	703
June	1st to 10th	Day	19% 13% 29% 24% 12% 3	870
	11th to 20th	Day	19% 11% 23% 29% 15% 3	870
	21st to end	Day	13% 9% 24% 28% 21% 6%	870
July	1st to 10th	Day	11% 7% 25% 29% 21% 6%	769
	11th to 20th	Day	9% 9% 22% 33% 21% 5%	668
	21st to end	Day	8% 6% 20% 35% 23% 7%	635
August	1st to 10th	Day	7% 5% 15% 35% 26% 11%	487
	11th to 20th	Day	7% 8% 21% 30% 22% 11%	477
	21st to end	Day	12% 7% 24% 27% 22% 8%	539
September	1st to 10th	Day	11% 12% 25% 29% 16% 8%	490
	11th to 20th	Day	14% 10% 18% 28% 22% 7%	490
	21st to end	Day	21% 12% 28% 23% 13% 3	490
October	1st to 10th	Day	22% 12% 22% 21% 17% 6%	490
	11th to 20th	Day	21% 19% 24% 19% 13% 4	468
	21st to end	Day	23% 17% 27% 20% 12% 2	313
November	1st to 10th	Day	23% 22% 30% 16% 7% 2	180
	11th to 20th	Day	22% 18% 23% 22% 12% 3	180
	21st to end	Day	18% 19% 29% 19% 10% 4	180
December	1st to 10th	Day	14% 12% 26% 29% 14% 5%	180
	11th to 20th	Day	13% 21% 28% 21% 13% 4	180
	21st to end	Day	16% 18% 34% 20% 10% 2	198
January	1st to 10th	Night	22% 15% 32% 21% 9% 1	855
	11th to 20th	Night	19% 13% 28% 28% 12% 1	850
	21st to end	Night	15% 16% 29% 26% 11% 2	866
February	1st to 10th	Night	19% 16% 30% 23% 11% 1	760
	11th to 20th	Night	14% 11% 29% 35% 9% 1	744
	21st to end	Night	14% 12% 27% 31% 14% 2	628
March	1st to 10th	Night	15% 15% 27% 27% 14% 2	760
	11th to 20th	Night	11% 16% 32% 26% 12% 2	760
	21st to end	Night	12% 17% 23% 27% 19% 3	836
April	1st to 10th	Night	13% 12% 27% 28% 16% 3	760
	11th to 20th	Night	12% 11% 29% 30% 17% 2	678
	21st to end	Night	12% 13% 30% 28% 14% 3	390
May	1st to 10th	Night	13% 12% 23% 32% 18% 2	380
	11th to 20th	Night	15% 9% 22% 33% 17% 3	374
	21st to end	Night	18% 8% 23% 27% 22% 2	411
June	1st to 10th	Night	18% 10% 27% 29% 15% 1	380
	11th to 20th	Night	20% 8% 24% 29% 17% 2	380
	21st to end	Night	13% 6% 22% 35% 20% 5%	380
July	1st to 10th	Night	13% 6% 19% 32% 27% 2	370
	11th to 20th	Night	9% 7% 21% 34% 26% 3	368
	21st to end	Night	9% 6% 18% 33% 30% 5%	416
August	1st to 10th	Night	6% 3 14% 35% 36% 7%	378
	11th to 20th	Night	8% 5% 11% 36% 34% 6%	414
	21st to end	Night	12% 7% 19% 31% 27% 5%	707
September	1st to 10th	Night	11% 6% 19% 36% 24% 3	760
	11th to 20th	Night	13% 5% 16% 30% 30% 6%	760
	21st to end	Night	18% 10% 24% 30% 14% 3	760
October	1st to 10th	Night	20% 11% 19% 29% 18% 3	760
	11th to 20th	Night	18% 12% 24% 28% 16% 2	760
	21st to end	Night	21% 13% 30% 23% 11% 2	836
November	1st to 10th	Night	25% 15% 24% 25% 9% 2	742
	11th to 20th	Night	21% 15% 29% 24% 9% 1	760
	21st to end	Night	20% 17% 27% 26% 9% 2	872
December	1st to 10th	Night	17% 15% 25% 29% 13% 2	999
	11th to 20th	Night	19% 16% 29% 27% 8% 1	1040
	21st to end	Night	18% 16% 31% 26% 9% 1	1144

Page generated at 2024-10-29 08:20:50. Version ac07

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