Fernie Alpine Resort
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fernie Alpine Resort clear sky chart from 2005-11-06 to 2026-01-17.

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	12% 15% 4 8% 5% 4 4 3 5% 6% 34%	131401
	Night	12% 18% 5% 8% 4 4 4 3 5% 6% 31%	128993
Transparency	Day	49% 6% 14% 19% 10% 2	131115
	Night	53% 7% 14% 17% 8% 1	128856
Seeing	Day	21% 17% 28% 23% 10% 2	16688
	Night	21% 11% 27% 30% 11% 1	25931

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	9% 28% 17% 20% 6% 4 2 2 2 3 7%	3249
	11th to 20th	Day	9% 17% 4 13% 12% 8% 6% 3 4 4 21%	3613
	21st to end	Day	13% 27% 4 8% 3 3 3 3 5% 6% 24%	4004
February	1st to 10th	Day	13% 23% 7% 13% 6% 4 3 3 3 7% 18%	1600
	11th to 20th	Day	11% 23% 7% 13% 6% 3 4 4 5% 6% 18%	1782
	21st to end	Day	8% 28% 8% 12% 6% 5% 4 4 5% 4 18%	1650
March	1st to 10th	Day	8% 21% 8% 10% 5% 4 3 3 5% 7% 27%	4518
	11th to 20th	Day	9% 28% 7% 9% 4 3 3 2 3 4 30%	4866
	21st to end	Day	14% 31% 5% 10% 5% 4 3 2 4 5% 16%	5660
April	1st to 10th	Day	13% 22% 4 10% 5% 4 5% 4 5% 7% 21%	2400
	11th to 20th	Day	14% 19% 5% 8% 6% 4 4 3 5% 6% 25%	2561
	21st to end	Day	15% 17% 4 8% 6% 4 5% 4 5% 6% 26%	2600
May	1st to 10th	Day	15% 13% 4 7% 5% 4 4 3 5% 6% 36%	6073
	11th to 20th	Day	13% 16% 4 10% 6% 6% 6% 4 6% 7% 20%	6522
	21st to end	Day	16% 11% 3 7% 5% 5% 5% 4 6% 7% 31%	7405
June	1st to 10th	Day	21% 10% 3 7% 5% 5% 5% 3 6% 8% 27%	3000
	11th to 20th	Day	21% 10% 3 7% 6% 5% 6% 5% 6% 6% 24%	3000
	21st to end	Day	12% 7% 2 6% 5% 5% 5% 5% 7% 7% 41%	3000
July	1st to 10th	Day	6% 4 2 5% 4 3 4 3 6% 7% 57%	6780
	11th to 20th	Day	6% 3 1 3 3 3 3 3 5% 8% 63%	6734
	21st to end	Day	6% 3 1 3 3 3 3 3 6% 9% 60%	6874
August	1st to 10th	Day	6% 4 1 4 3 3 5% 4 8% 10% 52%	4541
	11th to 20th	Day	7% 3 2 4 3 3 4 4 6% 8% 58%	4197
	21st to end	Day	9% 5% 2 5% 4 4 4 3 6% 7% 52%	4664
September	1st to 10th	Day	10% 5% 2 5% 3 3 4 3 6% 7% 52%	2408
	11th to 20th	Day	14% 8% 2 5% 4 4 4 3 5% 7% 45%	2211
	21st to end	Day	15% 10% 3 5% 3 3 3 3 5% 7% 44%	2200
October	1st to 10th	Day	11% 8% 1 6% 4 4 4 3 5% 8% 46%	3544
	11th to 20th	Day	20% 9% 2 6% 3 3 4 3 5% 7% 37%	2964
	21st to end	Day	19% 20% 6% 8% 5% 4 4 2 4 5% 25%	3200
November	1st to 10th	Day	24% 21% 6% 9% 4 4 3 4 4 5% 16%	1845
	11th to 20th	Day	19% 24% 6% 11% 4 3 3 3 4 5% 18%	1619
	21st to end	Day	16% 24% 7% 11% 5% 4 4 3 4 5% 16%	1470
December	1st to 10th	Day	13% 16% 4 14% 9% 5% 5% 5% 5% 6% 19%	2360
	11th to 20th	Day	15% 29% 10% 13% 6% 4 3 2 3 4 12%	2712
	21st to end	Day	10% 31% 11% 14% 6% 4 3 3 4 4 10%	3575
January	1st to 10th	Night	10% 33% 13% 15% 5% 4 4 2 3 3 9%	6916
	11th to 20th	Night	9% 14% 5% 14% 8% 6% 5% 3 4 6% 24%	6460
	21st to end	Night	13% 26% 5% 8% 4 4 3 4 4 5% 26%	6952
February	1st to 10th	Night	14% 23% 6% 12% 6% 4 3 3 4 4 21%	2800
	11th to 20th	Night	11% 25% 5% 12% 6% 4 3 3 3 5% 22%	2502
	21st to end	Night	8% 25% 8% 12% 6% 4 4 3 4 4 22%	1980
March	1st to 10th	Night	8% 21% 7% 11% 3 3 3 3 5% 6% 30%	5376
	11th to 20th	Night	9% 27% 6% 7% 4 3 3 2 4 4 30%	5133
	21st to end	Night	14% 35% 5% 8% 4 3 3 3 4 5% 16%	5314
April	1st to 10th	Night	12% 20% 3 8% 4 4 3 3 7% 8% 30%	2000
	11th to 20th	Night	16% 15% 3 6% 4 4 4 4 5% 6% 32%	1789
	21st to end	Night	13% 17% 3 7% 5% 4 3 4 5% 7% 32%	1800
May	1st to 10th	Night	14% 11% 3 8% 4 5% 4 4 5% 6% 38%	3882
	11th to 20th	Night	15% 15% 3 8% 5% 5% 5% 4 5% 7% 27%	3357
	21st to end	Night	18% 10% 2 6% 4 4 5% 3 5% 6% 37%	3470
June	1st to 10th	Night	21% 7% 2 7% 4 5% 5% 3 6% 7% 33%	1400
	11th to 20th	Night	22% 7% 2 4 5% 5% 6% 4 7% 6% 31%	1400
	21st to end	Night	9% 4 2 6% 4 4 5% 5% 7% 10% 45%	1400
July	1st to 10th	Night	6% 3 1 4 3 3 4 3 4 7% 60%	3180
	11th to 20th	Night	6% 2 1 3 3 2 3 3 5% 7% 64%	3222
	21st to end	Night	6% 3 1 3 2 2 3 3 4 7% 66%	3969
August	1st to 10th	Night	5% 3 1 4 3 3 3 3 5% 10% 60%	2609
	11th to 20th	Night	5% 3 2 5% 3 4 4 4 6% 10% 54%	2861
	21st to end	Night	7% 4 1 4 3 3 4 3 6% 9% 56%	3245
September	1st to 10th	Night	8% 3 2 4 3 3 3 4 6% 7% 58%	1990
	11th to 20th	Night	13% 6% 2 5% 4 4 4 3 5% 7% 48%	2188
	21st to end	Night	15% 7% 2 5% 3 3 3 3 5% 7% 48%	2200
October	1st to 10th	Night	11% 8% 2 4 3 3 3 3 5% 8% 50%	3654
	11th to 20th	Night	17% 9% 2 4 2 2 3 3 5% 6% 45%	4182
	21st to end	Night	16% 17% 4 6% 4 4 5% 3 5% 5% 31%	4600
November	1st to 10th	Night	25% 19% 4 6% 4 3 3 3 5% 7% 21%	2665
	11th to 20th	Night	17% 29% 5% 9% 4 3 2 3 4 5% 20%	2984
	21st to end	Night	18% 27% 6% 9% 4 3 3 3 4 5% 18%	3150
December	1st to 10th	Night	11% 18% 6% 12% 6% 4 4 4 5% 7% 23%	5040
	11th to 20th	Night	11% 30% 9% 14% 7% 5% 4 3 4 4 9%	5700
	21st to end	Night	11% 33% 10% 13% 6% 4 4 3 4 3 10%	7623

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	83% 6% 5% 5% 1	3249
	11th to 20th	Day	64% 8% 11% 9% 5% 3	3637
	21st to end	Day	61% 8% 13% 13% 4	4004
February	1st to 10th	Day	68% 6% 12% 9% 4 1	1600
	11th to 20th	Day	65% 9% 12% 10% 4	1791
	21st to end	Day	67% 6% 11% 11% 5%	1650
March	1st to 10th	Day	55% 6% 13% 15% 10%	4518
	11th to 20th	Day	58% 6% 22% 12% 3	4867
	21st to end	Day	70% 5% 11% 10% 4	5660
April	1st to 10th	Day	61% 6% 16% 15% 2	2400
	11th to 20th	Day	58% 4 17% 18% 3	2561
	21st to end	Day	56% 5% 15% 19% 4 1	2600
May	1st to 10th	Day	48% 4 12% 24% 12%	6073
	11th to 20th	Day	57% 9% 15% 16% 3	6526
	21st to end	Day	49% 7% 19% 21% 5%	7406
June	1st to 10th	Day	55% 5% 14% 18% 8% 1	3000
	11th to 20th	Day	57% 6% 14% 16% 7% 1	3000
	21st to end	Day	39% 6% 18% 25% 12% 1	3000
July	1st to 10th	Day	25% 5% 13% 26% 25% 8%	6706
	11th to 20th	Day	21% 4 13% 25% 28% 10%	6653
	21st to end	Day	21% 4 12% 33% 20% 10%	6681
August	1st to 10th	Day	24% 6% 15% 29% 21% 4	4524
	11th to 20th	Day	24% 5% 20% 37% 13% 1	4236
	21st to end	Day	30% 5% 17% 32% 15% 1	4663
September	1st to 10th	Day	30% 4 17% 30% 16% 3	2408
	11th to 20th	Day	38% 5% 15% 30% 11% 2	2211
	21st to end	Day	40% 6% 21% 22% 10%	2200
October	1st to 10th	Day	35% 6% 20% 34% 5%	3544
	11th to 20th	Day	46% 6% 18% 23% 8%	2964
	21st to end	Day	60% 7% 14% 13% 6%	3200
November	1st to 10th	Day	69% 9% 9% 10% 3	1845
	11th to 20th	Day	69% 7% 13% 8% 4	1619
	21st to end	Day	68% 9% 12% 7% 3	1470
December	1st to 10th	Day	63% 12% 13% 10% 2	2360
	11th to 20th	Day	77% 6% 11% 5% 1	2714
	21st to end	Day	74% 12% 6% 6% 2	3575
January	1st to 10th	Night	81% 6% 5% 6% 1	6916
	11th to 20th	Night	60% 8% 10% 10% 9% 3	6498
	21st to end	Night	61% 7% 14% 13% 5%	6952
February	1st to 10th	Night	67% 5% 10% 10% 7% 1	2800
	11th to 20th	Night	65% 5% 14% 11% 6%	2503
	21st to end	Night	64% 6% 12% 12% 6% 1	1980
March	1st to 10th	Night	54% 4 18% 13% 11%	5376
	11th to 20th	Night	56% 7% 20% 15% 3	5133
	21st to end	Night	71% 6% 12% 10% 2	5314
April	1st to 10th	Night	51% 7% 20% 16% 6%	2000
	11th to 20th	Night	51% 5% 16% 23% 6%	1789
	21st to end	Night	50% 6% 15% 22% 6% 1	1800
May	1st to 10th	Night	46% 5% 13% 22% 14%	3879
	11th to 20th	Night	52% 7% 15% 19% 7%	3357
	21st to end	Night	46% 6% 17% 23% 8%	3470
June	1st to 10th	Night	48% 6% 19% 21% 6% 1	1400
	11th to 20th	Night	49% 6% 17% 18% 9% 1	1400
	21st to end	Night	32% 6% 21% 27% 13% 2	1400
July	1st to 10th	Night	22% 6% 14% 27% 22% 9%	3145
	11th to 20th	Night	19% 3 17% 23% 27% 11%	3180
	21st to end	Night	18% 4 19% 28% 21% 10%	3857
August	1st to 10th	Night	20% 5% 20% 28% 22% 5%	2601
	11th to 20th	Night	25% 5% 24% 28% 17% 2	2888
	21st to end	Night	24% 5% 19% 32% 18% 2	3245
September	1st to 10th	Night	24% 4 14% 35% 18% 6%	1990
	11th to 20th	Night	33% 6% 17% 29% 13% 2	2188
	21st to end	Night	37% 5% 22% 23% 13% 1	2200
October	1st to 10th	Night	32% 7% 21% 32% 8%	3654
	11th to 20th	Night	39% 5% 16% 28% 11%	4182
	21st to end	Night	52% 9% 17% 18% 4	4600
November	1st to 10th	Night	64% 8% 13% 12% 3 1	2665
	11th to 20th	Night	67% 6% 12% 10% 4	2984
	21st to end	Night	68% 8% 11% 9% 3	3150
December	1st to 10th	Night	59% 11% 17% 11% 2	5040
	11th to 20th	Night	79% 8% 8% 4 1	5697
	21st to end	Night	77% 9% 7% 5% 2	7623

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	24% 24% 23% 18% 8% 2	220
	11th to 20th	Day	21% 19% 35% 17% 7% 2	212
	21st to end	Day	16% 24% 38% 13% 5% 4	220
February	1st to 10th	Day	22% 21% 39% 15% 3 1	200
	11th to 20th	Day	18% 20% 30% 28% 4	335
	21st to end	Day	26% 20% 35% 15% 4	414
March	1st to 10th	Day	30% 22% 25% 16% 7% 1	500
	11th to 20th	Day	27% 18% 25% 21% 8% 1	500
	21st to end	Day	32% 19% 24% 18% 6% 1	550
April	1st to 10th	Day	27% 20% 30% 17% 5% 1	500
	11th to 20th	Day	26% 23% 26% 19% 6% 1	492
	21st to end	Day	22% 21% 28% 20% 7% 2	500
May	1st to 10th	Day	22% 15% 28% 23% 9% 2	503
	11th to 20th	Day	21% 14% 24% 25% 14% 2	630
	21st to end	Day	26% 12% 21% 26% 14% 2	789
June	1st to 10th	Day	23% 17% 25% 24% 9% 1	730
	11th to 20th	Day	26% 17% 25% 20% 11% 1	730
	21st to end	Day	15% 12% 27% 28% 15% 2	730
July	1st to 10th	Day	11% 10% 28% 30% 19% 2	721
	11th to 20th	Day	10% 12% 31% 32% 14% 1	698
	21st to end	Day	9% 13% 33% 27% 15% 3	575
August	1st to 10th	Day	9% 14% 33% 29% 13% 3	527
	11th to 20th	Day	9% 12% 34% 27% 15% 3	517
	21st to end	Day	13% 16% 29% 26% 12% 3	583
September	1st to 10th	Day	15% 19% 27% 25% 12% 2	530
	11th to 20th	Day	18% 14% 29% 25% 12% 3	530
	21st to end	Day	27% 19% 28% 18% 6% 1	530
October	1st to 10th	Day	22% 16% 30% 22% 9% 1	500
	11th to 20th	Day	29% 16% 25% 17% 11% 2	330
	21st to end	Day	31% 18% 27% 20% 5%	363
November	1st to 10th	Day	33% 12% 28% 25% 2	330
	11th to 20th	Day	34% 21% 25% 17% 3	297
	21st to end	Day	26% 20% 29% 14% 8% 4	220
December	1st to 10th	Day	29% 20% 26% 17% 7% 1	220
	11th to 20th	Day	27% 18% 30% 21% 2 1	220
	21st to end	Day	19% 19% 37% 19% 6% 1	242
January	1st to 10th	Night	26% 20% 27% 20% 6% 1	1050
	11th to 20th	Night	22% 19% 30% 22% 7%	866
	21st to end	Night	17% 14% 35% 27% 6% 1	880
February	1st to 10th	Night	22% 14% 34% 23% 6% 1	800
	11th to 20th	Night	21% 12% 35% 27% 5%	784
	21st to end	Night	18% 15% 30% 27% 10% 1	660
March	1st to 10th	Night	23% 14% 28% 27% 9%	800
	11th to 20th	Night	26% 14% 23% 27% 10% 1	800
	21st to end	Night	24% 14% 26% 25% 9% 1	880
April	1st to 10th	Night	20% 10% 28% 31% 11%	800
	11th to 20th	Night	20% 13% 29% 29% 8%	601
	21st to end	Night	19% 13% 30% 28% 11%	600
May	1st to 10th	Night	19% 10% 22% 39% 10% 1	512
	11th to 20th	Night	15% 11% 21% 32% 20% 1	394
	21st to end	Night	24% 8% 18% 30% 18% 1	433
June	1st to 10th	Night	19% 9% 23% 33% 15% 1	400
	11th to 20th	Night	23% 8% 22% 33% 14%	400
	21st to end	Night	11% 6% 22% 43% 18% 1	400
July	1st to 10th	Night	7% 5% 16% 49% 22% 1	390
	11th to 20th	Night	6% 6% 21% 47% 19% 1	388
	21st to end	Night	5% 4 21% 51% 19% 1	438
August	1st to 10th	Night	6% 3 16% 45% 28% 2	398
	11th to 20th	Night	7% 5% 20% 41% 26% 2	566
	21st to end	Night	10% 5% 23% 44% 17% 1	660
September	1st to 10th	Night	9% 5% 23% 40% 21% 3	790
	11th to 20th	Night	13% 5% 20% 37% 22% 3	800
	21st to end	Night	19% 7% 25% 33% 13% 3	800
October	1st to 10th	Night	22% 6% 24% 37% 10% 1	800
	11th to 20th	Night	23% 8% 26% 33% 11%	800
	21st to end	Night	26% 9% 30% 27% 7%	880
November	1st to 10th	Night	32% 11% 28% 26% 3	820
	11th to 20th	Night	30% 16% 28% 20% 7%	1036
	21st to end	Night	27% 15% 28% 22% 8% 1	1050
December	1st to 10th	Night	26% 12% 30% 24% 7% 1	1050
	11th to 20th	Night	24% 18% 32% 21% 5%	1050
	21st to end	Night	23% 15% 31% 25% 6%	1155

Page generated at 2026-01-13 22:14:31. Version ac07

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