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 2026-09-14.

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	7% 9% 3 9% 6% 6% 6% 5% 7% 8% 34%	153421
	Night	7% 12% 4 10% 7% 6% 6% 5% 7% 7% 29%	146365
Transparency	Day	46% 5% 15% 23% 10% 1	153126
	Night	52% 6% 14% 19% 8% 1	146242
Seeing	Day	15% 14% 26% 26% 16% 5%	18447
	Night	16% 12% 25% 29% 16% 2	26432

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% 18% 7% 18% 9% 7% 6% 4 6% 6% 12%	4125
	11th to 20th	Day	6% 9% 3 8% 6% 7% 7% 6% 10% 8% 30%	4119
	21st to end	Day	5% 13% 4 12% 8% 5% 7% 5% 7% 9% 27%	4984
February	1st to 10th	Day	8% 19% 6% 13% 7% 6% 4 5% 5% 5% 22%	1743
	11th to 20th	Day	6% 14% 5% 12% 7% 6% 6% 4 6% 7% 27%	1845
	21st to end	Day	6% 14% 5% 14% 8% 5% 6% 4 6% 7% 25%	1605
March	1st to 10th	Day	4 12% 5% 11% 8% 7% 7% 5% 7% 8% 26%	4618
	11th to 20th	Day	2 9% 4 11% 7% 7% 7% 5% 8% 10% 28%	5037
	21st to end	Day	6% 12% 4 11% 8% 7% 6% 5% 7% 8% 26%	5913
April	1st to 10th	Day	5% 14% 5% 11% 8% 6% 7% 5% 7% 8% 24%	2520
	11th to 20th	Day	8% 13% 5% 11% 7% 6% 6% 5% 7% 7% 26%	2568
	21st to end	Day	8% 10% 4 9% 7% 8% 6% 5% 6% 7% 30%	2929
May	1st to 10th	Day	7% 9% 3 7% 5% 5% 5% 4 6% 8% 41%	8195
	11th to 20th	Day	8% 10% 4 11% 7% 7% 7% 5% 7% 8% 26%	8160
	21st to end	Day	11% 11% 4 10% 7% 6% 6% 5% 7% 9% 26%	9577
June	1st to 10th	Day	14% 10% 4 9% 6% 6% 6% 4 6% 7% 28%	3360
	11th to 20th	Day	14% 9% 4 10% 7% 6% 6% 5% 6% 8% 25%	3360
	21st to end	Day	10% 8% 3 9% 6% 6% 6% 5% 7% 7% 33%	3360
July	1st to 10th	Day	6% 5% 2 6% 4 5% 6% 5% 7% 9% 46%	9124
	11th to 20th	Day	4 4 2 5% 4 4 5% 4 6% 8% 54%	8820
	21st to end	Day	5% 4 2 5% 5% 5% 5% 4 7% 9% 47%	9235
August	1st to 10th	Day	4 3 2 5% 4 4 5% 4 6% 9% 56%	6441
	11th to 20th	Day	3 3 2 5% 4 5% 6% 5% 8% 12% 46%	6261
	21st to end	Day	9% 5% 2 6% 5% 5% 5% 4 7% 9% 43%	6373
September	1st to 10th	Day	9% 6% 2 6% 4 3 4 3 6% 8% 48%	2520
	11th to 20th	Day	11% 6% 3 7% 4 5% 4 4 5% 8% 43%	2437
	21st to end	Day	14% 9% 3 8% 5% 5% 5% 5% 6% 7% 33%	2129
October	1st to 10th	Day	12% 11% 3 10% 5% 5% 5% 4 6% 7% 31%	3280
	11th to 20th	Day	15% 10% 3 9% 5% 4 4 4 5% 8% 33%	3213
	21st to end	Day	9% 12% 5% 9% 6% 6% 6% 5% 7% 7% 28%	3141
November	1st to 10th	Day	11% 16% 5% 13% 6% 5% 6% 5% 5% 6% 22%	1648
	11th to 20th	Day	11% 12% 4 11% 7% 6% 6% 6% 7% 7% 23%	1680
	21st to end	Day	8% 19% 4 12% 8% 7% 7% 5% 7% 8% 17%	1533
December	1st to 10th	Day	7% 13% 4 12% 8% 9% 8% 6% 7% 7% 19%	2164
	11th to 20th	Day	5% 13% 5% 15% 8% 9% 8% 6% 8% 8% 15%	2322
	21st to end	Day	6% 17% 5% 12% 8% 6% 6% 4 6% 7% 21%	3082
January	1st to 10th	Night	7% 19% 7% 17% 8% 8% 6% 5% 6% 5% 11%	8788
	11th to 20th	Night	4 10% 4 10% 6% 7% 8% 7% 8% 7% 27%	8779
	21st to end	Night	5% 13% 6% 12% 7% 8% 7% 5% 7% 8% 23%	9194
February	1st to 10th	Night	8% 18% 7% 13% 7% 6% 4 3 5% 6% 22%	2873
	11th to 20th	Night	7% 14% 4 12% 7% 6% 5% 4 6% 6% 29%	2662
	21st to end	Night	5% 14% 6% 11% 7% 6% 7% 4 6% 7% 26%	2200
March	1st to 10th	Night	3 14% 6% 10% 6% 6% 6% 6% 8% 10% 25%	5496
	11th to 20th	Night	2 10% 4 11% 7% 6% 7% 7% 9% 10% 28%	5168
	21st to end	Night	6% 13% 5% 11% 7% 7% 7% 5% 6% 8% 26%	5303
April	1st to 10th	Night	5% 12% 5% 11% 8% 7% 6% 5% 6% 7% 28%	2100
	11th to 20th	Night	6% 13% 4 10% 7% 6% 6% 5% 7% 8% 30%	1998
	21st to end	Night	6% 10% 4 10% 7% 6% 7% 4 6% 7% 33%	1690
May	1st to 10th	Night	8% 10% 3 8% 5% 5% 5% 4 5% 7% 40%	4724
	11th to 20th	Night	10% 11% 4 10% 6% 6% 6% 5% 6% 7% 26%	4700
	21st to end	Night	15% 11% 4 9% 6% 5% 5% 5% 8% 8% 25%	4590
June	1st to 10th	Night	14% 9% 3 8% 7% 5% 6% 4 7% 7% 27%	1260
	11th to 20th	Night	15% 10% 4 9% 7% 5% 6% 5% 7% 7% 23%	1260
	21st to end	Night	10% 9% 3 8% 8% 7% 6% 5% 5% 6% 33%	1260
July	1st to 10th	Night	8% 6% 3 8% 5% 4 5% 5% 6% 8% 41%	3832
	11th to 20th	Night	6% 4 2 5% 4 5% 5% 4 7% 8% 49%	4140
	21st to end	Night	7% 5% 2 6% 4 5% 6% 5% 7% 9% 45%	4833
August	1st to 10th	Night	5% 4 2 7% 5% 5% 5% 4 5% 7% 52%	3709
	11th to 20th	Night	6% 6% 3 7% 5% 6% 6% 4 7% 9% 41%	3771
	21st to end	Night	11% 7% 3 8% 5% 4 5% 4 7% 8% 38%	4784
September	1st to 10th	Night	9% 4 2 6% 5% 5% 4 4 6% 7% 48%	2100
	11th to 20th	Night	9% 6% 2 6% 4 5% 5% 4 7% 8% 44%	2030
	21st to end	Night	12% 9% 3 7% 4 4 5% 5% 6% 8% 37%	2267
October	1st to 10th	Night	14% 10% 4 10% 5% 6% 5% 4 5% 6% 30%	3920
	11th to 20th	Night	10% 10% 3 8% 6% 5% 6% 5% 8% 9% 31%	3942
	21st to end	Night	10% 11% 4 9% 7% 6% 6% 4 6% 7% 29%	4654
November	1st to 10th	Night	13% 14% 4 11% 7% 6% 6% 5% 7% 8% 21%	2870
	11th to 20th	Night	9% 14% 4 11% 8% 6% 5% 5% 6% 7% 24%	2940
	21st to end	Night	8% 18% 6% 12% 9% 7% 6% 4 6% 7% 20%	3064
December	1st to 10th	Night	7% 12% 4 11% 7% 9% 8% 5% 7% 8% 21%	5234
	11th to 20th	Night	7% 20% 8% 14% 8% 7% 6% 5% 6% 6% 14%	6090
	21st to end	Night	6% 14% 6% 13% 8% 7% 7% 4 6% 7% 23%	8140

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	70% 5% 12% 10% 3	4125
	11th to 20th	Day	46% 8% 21% 14% 6% 4	4140
	21st to end	Day	53% 7% 19% 19% 2	4985
February	1st to 10th	Day	64% 3 11% 12% 10% 1	1743
	11th to 20th	Day	56% 5% 15% 16% 8%	1854
	21st to end	Day	57% 6% 14% 16% 6%	1605
March	1st to 10th	Day	54% 6% 10% 21% 9%	4618
	11th to 20th	Day	48% 3 14% 23% 11%	5037
	21st to end	Day	55% 5% 11% 20% 9%	5913
April	1st to 10th	Day	56% 7% 12% 18% 7%	2520
	11th to 20th	Day	56% 5% 11% 18% 10% 1	2568
	21st to end	Day	52% 5% 10% 20% 11% 1	2929
May	1st to 10th	Day	40% 3 10% 30% 15% 1	8195
	11th to 20th	Day	53% 4 11% 25% 7%	8163
	21st to end	Day	54% 5% 13% 22% 6%	9578
June	1st to 10th	Day	54% 6% 9% 16% 12% 3	3360
	11th to 20th	Day	56% 6% 12% 18% 8% 1	3360
	21st to end	Day	48% 6% 16% 20% 9% 1	3360
July	1st to 10th	Day	33% 4 14% 27% 16% 6%	9049
	11th to 20th	Day	27% 5% 13% 31% 21% 4	8739
	21st to end	Day	31% 5% 17% 28% 16% 3	9035
August	1st to 10th	Day	26% 4 14% 35% 20% 2	6424
	11th to 20th	Day	28% 7% 23% 34% 8% 1	6303
	21st to end	Day	38% 5% 24% 25% 7% 1	6372
September	1st to 10th	Day	35% 5% 19% 27% 11% 3	2520
	11th to 20th	Day	41% 4 14% 28% 11% 2	2437
	21st to end	Day	49% 6% 15% 18% 10% 1	2129
October	1st to 10th	Day	52% 4 21% 18% 5%	3280
	11th to 20th	Day	50% 3 17% 24% 5%	3213
	21st to end	Day	54% 7% 19% 18% 3	3141
November	1st to 10th	Day	60% 6% 12% 16% 6%	1648
	11th to 20th	Day	59% 6% 15% 15% 4	1680
	21st to end	Day	64% 6% 13% 11% 5%	1533
December	1st to 10th	Day	62% 8% 19% 10% 1	2164
	11th to 20th	Day	64% 7% 17% 8% 4	2324
	21st to end	Day	61% 5% 15% 15% 4	3082
January	1st to 10th	Night	73% 4 10% 9% 3	8788
	11th to 20th	Night	50% 10% 17% 14% 5% 3	8820
	21st to end	Night	57% 8% 17% 17% 2	9194
February	1st to 10th	Night	63% 3 10% 14% 8% 1	2873
	11th to 20th	Night	56% 5% 13% 18% 7% 1	2664
	21st to end	Night	55% 6% 14% 18% 7% 1	2200
March	1st to 10th	Night	51% 6% 10% 20% 12%	5496
	11th to 20th	Night	46% 3 15% 25% 11%	5169
	21st to end	Night	55% 5% 13% 16% 10%	5303
April	1st to 10th	Night	53% 6% 14% 20% 6% 1	2100
	11th to 20th	Night	51% 5% 11% 22% 11%	1998
	21st to end	Night	49% 5% 10% 22% 13% 1	1690
May	1st to 10th	Night	44% 3 9% 30% 13% 1	4721
	11th to 20th	Night	54% 5% 11% 24% 6%	4700
	21st to end	Night	54% 5% 15% 22% 4	4594
June	1st to 10th	Night	53% 6% 8% 20% 10% 3	1260
	11th to 20th	Night	58% 6% 13% 15% 8%	1260
	21st to end	Night	51% 5% 14% 20% 8% 2	1260
July	1st to 10th	Night	40% 5% 12% 23% 15% 5%	3798
	11th to 20th	Night	31% 5% 13% 30% 18% 2	4098
	21st to end	Night	34% 6% 14% 28% 13% 4	4728
August	1st to 10th	Night	32% 4 11% 33% 18% 3	3701
	11th to 20th	Night	38% 6% 20% 27% 9% 1	3795
	21st to end	Night	42% 5% 24% 21% 7% 1	4784
September	1st to 10th	Night	33% 6% 16% 29% 14% 2	2100
	11th to 20th	Night	36% 5% 16% 28% 12% 3	2030
	21st to end	Night	44% 6% 17% 21% 11% 1	2267
October	1st to 10th	Night	54% 4 19% 18% 5%	3920
	11th to 20th	Night	48% 6% 17% 24% 5%	3942
	21st to end	Night	52% 7% 18% 18% 4	4654
November	1st to 10th	Night	59% 7% 14% 15% 5%	2870
	11th to 20th	Night	58% 7% 15% 13% 6%	2940
	21st to end	Night	64% 5% 14% 11% 5%	3064
December	1st to 10th	Night	59% 8% 20% 10% 3	5234
	11th to 20th	Night	69% 7% 12% 8% 3	6087
	21st to end	Night	61% 5% 16% 15% 4	8140

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	17% 18% 35% 19% 7% 4	220
	11th to 20th	Day	12% 22% 28% 24% 13% 1	220
	21st to end	Day	20% 14% 31% 23% 11% 1	242
February	1st to 10th	Day	19% 19% 32% 18% 8% 4	283
	11th to 20th	Day	14% 14% 32% 28% 11% 1	425
	21st to end	Day	13% 21% 32% 21% 11% 3	381
March	1st to 10th	Day	16% 21% 27% 22% 12% 1	540
	11th to 20th	Day	14% 22% 29% 21% 11% 3	540
	21st to end	Day	17% 22% 26% 20% 11% 3	594
April	1st to 10th	Day	16% 21% 26% 25% 10% 2	540
	11th to 20th	Day	15% 23% 23% 21% 11% 6%	532
	21st to end	Day	14% 15% 29% 24% 14% 4	540
May	1st to 10th	Day	13% 16% 30% 25% 13% 3	543
	11th to 20th	Day	15% 13% 23% 26% 18% 5%	568
	21st to end	Day	19% 11% 23% 27% 16% 4	811
June	1st to 10th	Day	17% 13% 30% 25% 12% 3	990
	11th to 20th	Day	18% 12% 23% 28% 15% 4	990
	21st to end	Day	12% 8% 24% 29% 21% 6%	990
July	1st to 10th	Day	10% 9% 25% 29% 20% 6%	879
	11th to 20th	Day	9% 8% 24% 33% 21% 5%	768
	21st to end	Day	7% 6% 21% 33% 24% 8%	734
August	1st to 10th	Day	7% 6% 17% 33% 27% 10%	567
	11th to 20th	Day	7% 8% 22% 29% 22% 11%	557
	21st to end	Day	12% 7% 22% 27% 21% 11%	627
September	1st to 10th	Day	11% 11% 23% 27% 18% 10%	570
	11th to 20th	Day	13% 10% 19% 29% 22% 7%	543
	21st to end	Day	21% 12% 28% 23% 12% 3	530
October	1st to 10th	Day	22% 13% 22% 22% 16% 6%	530
	11th to 20th	Day	21% 19% 24% 19% 13% 4	507
	21st to end	Day	23% 17% 26% 21% 11% 1	344
November	1st to 10th	Day	22% 23% 33% 13% 6% 3	220
	11th to 20th	Day	23% 16% 25% 23% 11% 2	220
	21st to end	Day	16% 19% 27% 24% 10% 4	220
December	1st to 10th	Day	14% 11% 27% 30% 14% 4	220
	11th to 20th	Day	14% 19% 30% 22% 12% 3	220
	21st to end	Day	16% 18% 33% 21% 11% 2	242
January	1st to 10th	Night	21% 14% 31% 24% 9% 1	955
	11th to 20th	Night	17% 13% 28% 29% 11% 1	950
	21st to end	Night	14% 15% 29% 29% 12% 2	960
February	1st to 10th	Night	18% 16% 29% 23% 11% 2	840
	11th to 20th	Night	14% 11% 29% 36% 9% 1	824
	21st to end	Night	13% 13% 28% 31% 14% 2	692
March	1st to 10th	Night	15% 15% 26% 29% 13% 2	840
	11th to 20th	Night	11% 17% 32% 27% 11% 2	840
	21st to end	Night	13% 17% 23% 27% 18% 3	924
April	1st to 10th	Night	13% 12% 25% 30% 17% 3	840
	11th to 20th	Night	11% 11% 28% 30% 17% 2	750
	21st to end	Night	11% 14% 29% 29% 15% 2	430
May	1st to 10th	Night	13% 13% 23% 32% 18% 2	420
	11th to 20th	Night	14% 10% 23% 32% 17% 3	414
	21st to end	Night	19% 8% 23% 28% 21% 2	455
June	1st to 10th	Night	18% 10% 28% 29% 14% 1	420
	11th to 20th	Night	19% 8% 23% 30% 18% 1	420
	21st to end	Night	12% 6% 21% 36% 21% 5%	420
July	1st to 10th	Night	12% 6% 19% 32% 27% 2	410
	11th to 20th	Night	9% 6% 21% 36% 25% 3	408
	21st to end	Night	8% 6% 18% 33% 30% 5%	460
August	1st to 10th	Night	6% 3 14% 36% 35% 6%	418
	11th to 20th	Night	8% 5% 12% 37% 32% 5%	458
	21st to end	Night	12% 6% 18% 31% 28% 6%	781
September	1st to 10th	Night	11% 6% 19% 36% 25% 4	840
	11th to 20th	Night	13% 5% 16% 30% 30% 6%	812
	21st to end	Night	18% 11% 24% 31% 13% 3	800
October	1st to 10th	Night	20% 11% 19% 30% 18% 3	800
	11th to 20th	Night	18% 12% 25% 29% 16% 2	800
	21st to end	Night	21% 13% 29% 24% 11% 2	880
November	1st to 10th	Night	24% 15% 25% 26% 8% 2	820
	11th to 20th	Night	21% 15% 29% 24% 9% 1	840
	21st to end	Night	19% 16% 27% 27% 9% 2	964
December	1st to 10th	Night	17% 14% 25% 29% 13% 2	1111
	11th to 20th	Night	19% 16% 29% 26% 9% 1	1160
	21st to end	Night	18% 16% 32% 25% 9% 1	1276

Page generated at 2026-09-11 01:11:51. Version ac07

Copyright © 2026 Attilla Danko.