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 2024-01-14.

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	14% 14% 4 7% 6% 3 4 4 5% 6% 31%	74605
	Night	15% 17% 5% 7% 5% 3 4 4 5% 6% 30%	75156
Transparency	Day	52% 6% 14% 18% 8% 1	74298
	Night	55% 6% 14% 17% 7% 1	74981
Seeing	Day	21% 16% 28% 23% 10% 2	14063
	Night	21% 11% 27% 30% 11% 1	23353

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	17% 26% 9% 14% 5% 4 4 3 3 5% 11%	1329
	11th to 20th	Day	16% 25% 7% 10% 6% 3 5% 4 4 5% 15%	1441
	21st to end	Day	11% 23% 8% 14% 9% 4 4 4 4 5% 13%	1584
February	1st to 10th	Day	15% 22% 8% 10% 7% 3 4 3 3 7% 18%	1440
	11th to 20th	Day	13% 22% 8% 10% 7% 3 4 5% 5% 6% 17%	1598
	21st to end	Day	8% 24% 9% 10% 8% 4 5% 4 4 4 19%	1480
March	1st to 10th	Day	15% 25% 8% 9% 5% 3 3 4 4 4 20%	1800
	11th to 20th	Day	17% 25% 4 5% 5% 2 4 4 5% 6% 23%	1924
	21st to end	Day	17% 26% 6% 8% 6% 3 4 3 4 5% 17%	2249
April	1st to 10th	Day	14% 20% 5% 9% 7% 3 5% 5% 5% 7% 20%	2160
	11th to 20th	Day	16% 18% 5% 7% 7% 3 5% 4 5% 6% 24%	2301
	21st to end	Day	16% 16% 5% 7% 6% 3 5% 5% 5% 6% 26%	2340
May	1st to 10th	Day	15% 13% 4 8% 5% 3 4 5% 6% 8% 29%	2416
	11th to 20th	Day	13% 10% 2 7% 6% 4 6% 6% 7% 9% 31%	2568
	21st to end	Day	23% 11% 3 5% 7% 4 5% 5% 5% 6% 25%	2917
June	1st to 10th	Day	23% 9% 4 7% 6% 3 5% 4 5% 8% 25%	2700
	11th to 20th	Day	23% 9% 4 7% 6% 4 7% 6% 6% 6% 22%	2700
	21st to end	Day	12% 6% 2 5% 5% 3 6% 5% 7% 7% 42%	2700
July	1st to 10th	Day	7% 4 2 4 5% 3 5% 4 7% 8% 51%	2700
	11th to 20th	Day	7% 4 1 4 4 3 4 5% 5% 8% 54%	2682
	21st to end	Day	4 3 1 4 3 3 4 3 5% 8% 62%	2741
August	1st to 10th	Day	6% 4 2 3 5% 2 4 5% 5% 9% 56%	2507
	11th to 20th	Day	7% 3 2 3 3 3 5% 4 5% 8% 58%	2325
	21st to end	Day	9% 5% 2 4 5% 3 4 4 6% 7% 50%	2574
September	1st to 10th	Day	11% 6% 2 5% 4 3 3 4 6% 7% 50%	2168
	11th to 20th	Day	14% 7% 3 5% 5% 3 3 4 5% 7% 45%	1991
	21st to end	Day	16% 10% 3 5% 4 2 4 3 5% 6% 42%	1980
October	1st to 10th	Day	17% 10% 2 6% 5% 3 4 4 6% 7% 34%	1954
	11th to 20th	Day	20% 11% 4 6% 6% 3 4 4 4 5% 33%	1638
	21st to end	Day	22% 16% 4 5% 4 3 3 3 5% 7% 28%	1782
November	1st to 10th	Day	26% 19% 7% 7% 4 2 4 4 4 5% 17%	1667
	11th to 20th	Day	19% 21% 6% 10% 5% 2 3 4 5% 5% 20%	1465
	21st to end	Day	18% 21% 8% 9% 6% 3 4 4 5% 6% 17%	1330
December	1st to 10th	Day	17% 23% 7% 12% 7% 3 4 4 3 4 16%	1330
	11th to 20th	Day	16% 30% 8% 11% 8% 2 3 3 3 4 12%	1682
	21st to end	Day	14% 26% 7% 10% 8% 4 5% 5% 4 5% 12%	2442
January	1st to 10th	Night	20% 26% 9% 11% 6% 3 3 3 3 3 11%	2836
	11th to 20th	Night	17% 25% 7% 12% 6% 2 4 2 3 5% 17%	2606
	21st to end	Night	11% 24% 9% 11% 8% 4 4 4 4 5% 16%	2772
February	1st to 10th	Night	15% 22% 8% 10% 6% 3 3 3 4 5% 21%	2520
	11th to 20th	Night	13% 24% 6% 10% 7% 3 4 4 4 5% 21%	2246
	21st to end	Night	8% 21% 9% 11% 7% 4 4 4 4 5% 23%	1776
March	1st to 10th	Night	15% 23% 6% 7% 4 3 5% 4 5% 8% 20%	2160
	11th to 20th	Night	15% 23% 4 5% 4 3 4 4 5% 6% 26%	2035
	21st to end	Night	14% 24% 4 6% 5% 3 4 5% 5% 6% 24%	2106
April	1st to 10th	Night	12% 18% 3 7% 5% 3 3 5% 7% 8% 30%	1800
	11th to 20th	Night	17% 15% 4 6% 5% 3 4 5% 5% 6% 30%	1609
	21st to end	Night	13% 15% 4 7% 6% 3 3 4 4 8% 32%	1620
May	1st to 10th	Night	15% 11% 3 6% 5% 4 4 6% 5% 8% 34%	1542
	11th to 20th	Night	11% 10% 3 6% 5% 3 6% 5% 6% 7% 37%	1325
	21st to end	Night	20% 10% 3 6% 5% 3 6% 5% 6% 6% 28%	1358
June	1st to 10th	Night	21% 7% 2 6% 5% 3 6% 4 6% 8% 32%	1260
	11th to 20th	Night	24% 7% 2 4 5% 4 6% 5% 7% 6% 30%	1260
	21st to end	Night	9% 4 2 5% 5% 3 4 6% 7% 10% 45%	1260
July	1st to 10th	Night	5% 3 1 3 4 3 5% 4 5% 10% 57%	1260
	11th to 20th	Night	6% 3 1 3 3 2 4 4 5% 8% 61%	1274
	21st to end	Night	4 2 1 3 2 2 3 4 5% 6% 70%	1576
August	1st to 10th	Night	5% 2 1 3 4 2 3 4 5% 7% 63%	1432
	11th to 20th	Night	7% 1 1 3 2 2 4 4 5% 10% 61%	1576
	21st to end	Night	7% 3 2 4 4 2 4 3 4 8% 59%	1782
September	1st to 10th	Night	8% 4 2 4 4 2 3 4 6% 6% 57%	1790
	11th to 20th	Night	13% 6% 2 4 5% 3 4 4 5% 8% 47%	1968
	21st to end	Night	16% 8% 2 5% 4 2 3 4 5% 7% 45%	1980
October	1st to 10th	Night	16% 9% 3 5% 4 2 3 4 4 7% 43%	2006
	11th to 20th	Night	19% 10% 3 5% 3 3 4 5% 6% 7% 37%	2320
	21st to end	Night	20% 16% 4 6% 4 3 4 4 5% 5% 29%	2574
November	1st to 10th	Night	27% 18% 4 5% 5% 3 3 4 5% 7% 21%	2405
	11th to 20th	Night	17% 25% 6% 8% 5% 2 3 3 4 5% 22%	2698
	21st to end	Night	20% 23% 7% 7% 5% 2 4 4 4 6% 19%	2850
December	1st to 10th	Night	17% 23% 7% 10% 7% 3 4 3 4 4 16%	2850
	11th to 20th	Night	15% 30% 8% 12% 8% 4 4 3 3 5% 10%	3510
	21st to end	Night	14% 24% 8% 11% 8% 4 6% 4 5% 4 12%	5214

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	76% 8% 8% 5% 2 1	1329
	11th to 20th	Day	71% 9% 12% 6% 2 1	1441
	21st to end	Day	72% 8% 8% 9% 3	1584
February	1st to 10th	Day	68% 5% 13% 10% 4 1	1440
	11th to 20th	Day	67% 9% 13% 9% 3	1607
	21st to end	Day	67% 7% 10% 11% 5%	1480
March	1st to 10th	Day	68% 5% 13% 11% 4	1800
	11th to 20th	Day	62% 6% 13% 15% 5%	1925
	21st to end	Day	70% 5% 13% 10% 3	2249
April	1st to 10th	Day	62% 6% 15% 15% 2	2160
	11th to 20th	Day	60% 4 16% 17% 2	2301
	21st to end	Day	57% 5% 16% 18% 3 1	2340
May	1st to 10th	Day	52% 5% 18% 19% 5% 1	2416
	11th to 20th	Day	48% 7% 20% 19% 6%	2572
	21st to end	Day	59% 5% 18% 14% 4	2918
June	1st to 10th	Day	57% 5% 15% 16% 6% 1	2700
	11th to 20th	Day	59% 6% 15% 15% 4 1	2700
	21st to end	Day	38% 6% 18% 25% 12% 1	2700
July	1st to 10th	Day	30% 5% 14% 29% 17% 4	2626
	11th to 20th	Day	27% 6% 12% 27% 22% 5%	2601
	21st to end	Day	21% 5% 10% 29% 29% 6%	2589
August	1st to 10th	Day	25% 6% 16% 28% 19% 6%	2490
	11th to 20th	Day	25% 4 18% 32% 19% 3	2325
	21st to end	Day	31% 5% 15% 28% 18% 2	2574
September	1st to 10th	Day	33% 4 16% 28% 16% 3	2168
	11th to 20th	Day	38% 5% 16% 28% 11% 2	1991
	21st to end	Day	42% 6% 21% 21% 10% 1	1980
October	1st to 10th	Day	47% 6% 19% 21% 6%	1954
	11th to 20th	Day	52% 6% 16% 20% 5%	1638
	21st to end	Day	56% 5% 18% 16% 5%	1782
November	1st to 10th	Day	69% 8% 9% 10% 3	1667
	11th to 20th	Day	67% 7% 14% 8% 4	1465
	21st to end	Day	67% 10% 13% 7% 3	1330
December	1st to 10th	Day	72% 6% 8% 10% 3	1330
	11th to 20th	Day	78% 6% 8% 7% 1	1684
	21st to end	Day	68% 15% 6% 7% 3	2442
January	1st to 10th	Night	79% 5% 6% 6% 3 1	2836
	11th to 20th	Night	72% 6% 10% 8% 2 1	2606
	21st to end	Night	68% 8% 10% 10% 4	2772
February	1st to 10th	Night	67% 5% 11% 10% 6% 1	2520
	11th to 20th	Night	65% 6% 14% 10% 4	2247
	21st to end	Night	62% 6% 11% 13% 6% 1	1776
March	1st to 10th	Night	63% 5% 15% 13% 4	2160
	11th to 20th	Night	57% 7% 14% 17% 5%	2035
	21st to end	Night	60% 7% 16% 13% 3	2106
April	1st to 10th	Night	50% 8% 20% 16% 6%	1800
	11th to 20th	Night	52% 4 15% 22% 5%	1609
	21st to end	Night	51% 5% 16% 22% 5% 1	1620
May	1st to 10th	Night	46% 6% 19% 20% 10%	1542
	11th to 20th	Night	42% 7% 20% 22% 8%	1325
	21st to end	Night	54% 5% 17% 19% 4	1358
June	1st to 10th	Night	50% 6% 19% 20% 5% 1	1260
	11th to 20th	Night	51% 6% 18% 17% 7%	1260
	21st to end	Night	32% 6% 21% 26% 13% 2	1260
July	1st to 10th	Night	21% 5% 19% 34% 16% 5%	1225
	11th to 20th	Night	22% 4 15% 27% 26% 6%	1232
	21st to end	Night	16% 4 11% 33% 29% 7%	1488
August	1st to 10th	Night	21% 5% 15% 32% 21% 6%	1424
	11th to 20th	Night	19% 4 15% 38% 21% 2	1576
	21st to end	Night	24% 5% 15% 31% 22% 3	1782
September	1st to 10th	Night	26% 4 14% 34% 17% 6%	1790
	11th to 20th	Night	34% 5% 17% 29% 13% 2	1968
	21st to end	Night	39% 5% 21% 21% 13% 2	1980
October	1st to 10th	Night	41% 5% 19% 28% 7% 1	2006
	11th to 20th	Night	45% 5% 21% 22% 7% 1	2320
	21st to end	Night	56% 6% 17% 16% 5%	2574
November	1st to 10th	Night	64% 7% 12% 12% 3 1	2405
	11th to 20th	Night	65% 6% 13% 11% 5%	2698
	21st to end	Night	67% 8% 12% 9% 3	2850
December	1st to 10th	Night	72% 5% 9% 11% 3	2850
	11th to 20th	Night	78% 7% 9% 5% 1	3507
	21st to end	Night	71% 12% 8% 6% 3	5214

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	22% 24% 22% 21% 9% 3	180
	11th to 20th	Day	23% 17% 30% 18% 9% 2	166
	21st to end	Day	15% 23% 41% 11% 5% 5%	176
February	1st to 10th	Day	21% 24% 40% 13% 3	160
	11th to 20th	Day	21% 18% 30% 27% 4	271
	21st to end	Day	21% 20% 38% 17% 5%	346
March	1st to 10th	Day	31% 22% 25% 14% 6%	420
	11th to 20th	Day	29% 16% 25% 20% 8% 1	420
	21st to end	Day	32% 19% 24% 17% 6% 1	462
April	1st to 10th	Day	26% 22% 28% 18% 6% 1	420
	11th to 20th	Day	27% 24% 25% 17% 6% 1	412
	21st to end	Day	22% 22% 27% 20% 7% 2	420
May	1st to 10th	Day	22% 15% 28% 23% 8% 2	423
	11th to 20th	Day	21% 15% 24% 24% 14% 2	539
	21st to end	Day	28% 12% 20% 24% 14% 2	679
June	1st to 10th	Day	24% 16% 24% 24% 10% 1	630
	11th to 20th	Day	26% 17% 26% 19% 11% 1	630
	21st to end	Day	14% 12% 26% 29% 16% 3	630
July	1st to 10th	Day	10% 10% 27% 31% 19% 2	621
	11th to 20th	Day	10% 13% 30% 32% 14% 1	600
	21st to end	Day	7% 13% 32% 29% 15% 3	487
August	1st to 10th	Day	8% 13% 33% 30% 12% 4	447
	11th to 20th	Day	8% 10% 33% 29% 16% 4	437
	21st to end	Day	13% 17% 29% 27% 12% 2	495
September	1st to 10th	Day	17% 21% 26% 24% 9% 2	450
	11th to 20th	Day	18% 15% 29% 24% 11% 2	450
	21st to end	Day	27% 18% 27% 20% 7% 1	450
October	1st to 10th	Day	23% 16% 29% 22% 10% 1	424
	11th to 20th	Day	27% 16% 26% 17% 12% 2	270
	21st to end	Day	31% 16% 28% 21% 5%	297
November	1st to 10th	Day	34% 10% 27% 26% 3	270
	11th to 20th	Day	31% 19% 27% 19% 4	243
	21st to end	Day	24% 19% 28% 15% 9% 4	180
December	1st to 10th	Day	29% 16% 27% 18% 8% 2	180
	11th to 20th	Day	21% 18% 34% 23% 2 1	180
	21st to end	Day	18% 19% 37% 19% 7% 1	198
January	1st to 10th	Night	26% 20% 27% 20% 6% 1	950
	11th to 20th	Night	23% 19% 29% 21% 8% 1	772
	21st to end	Night	18% 12% 35% 27% 6% 1	792
February	1st to 10th	Night	22% 13% 36% 23% 5% 1	720
	11th to 20th	Night	23% 12% 34% 26% 6%	704
	21st to end	Night	16% 13% 31% 28% 11% 1	592
March	1st to 10th	Night	23% 14% 29% 26% 8%	720
	11th to 20th	Night	27% 12% 23% 27% 10% 1	720
	21st to end	Night	25% 13% 26% 25% 9% 1	792
April	1st to 10th	Night	19% 10% 28% 32% 11%	720
	11th to 20th	Night	22% 13% 28% 28% 9%	541
	21st to end	Night	19% 12% 31% 28% 10%	540
May	1st to 10th	Night	19% 9% 23% 39% 10% 1	462
	11th to 20th	Night	14% 11% 21% 32% 20% 1	354
	21st to end	Night	25% 8% 18% 30% 18% 1	389
June	1st to 10th	Night	19% 9% 22% 33% 16% 1	360
	11th to 20th	Night	24% 8% 22% 33% 14%	360
	21st to end	Night	9% 6% 22% 43% 18% 1	360
July	1st to 10th	Night	6% 5% 16% 50% 22% 1	350
	11th to 20th	Night	6% 6% 22% 46% 18% 1	348
	21st to end	Night	4 4 21% 52% 20% 1	394
August	1st to 10th	Night	5% 4 16% 46% 28% 2	358
	11th to 20th	Night	6% 5% 20% 40% 27% 2	508
	21st to end	Night	9% 5% 23% 43% 18% 1	594
September	1st to 10th	Night	10% 5% 24% 40% 17% 3	710
	11th to 20th	Night	13% 5% 21% 36% 22% 3	720
	21st to end	Night	20% 6% 24% 32% 14% 4	720
October	1st to 10th	Night	21% 6% 24% 37% 11% 1	720
	11th to 20th	Night	22% 8% 25% 33% 11%	720
	21st to end	Night	27% 9% 28% 28% 8%	792
November	1st to 10th	Night	34% 10% 27% 26% 3	740
	11th to 20th	Night	28% 16% 28% 21% 7%	936
	21st to end	Night	27% 15% 27% 23% 8% 1	950
December	1st to 10th	Night	27% 11% 30% 25% 7% 1	950
	11th to 20th	Night	23% 18% 33% 22% 4	950
	21st to end	Night	23% 14% 31% 26% 6%	1045

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