Whiteshell Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Whiteshell Provincial Park clear sky chart from 2005-11-06 to 2024-02-05.

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	13% 10% 4 8% 7% 4 5% 5% 6% 7% 31%	77707
	Night	11% 11% 5% 9% 8% 4 6% 5% 5% 6% 30%	81197
Transparency	Day	51% 7% 14% 20% 7% 1	77390
	Night	53% 7% 13% 18% 8% 1	81047
Seeing	Day	18% 16% 35% 22% 8% 2	15120
	Night	17% 12% 34% 27% 9% 1	25231

By Month

Percentage Cloud Cover NE (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	6% 15% 9% 14% 8% 6% 7% 6% 6% 5% 20%	2218
	11th to 20th	Day	5% 8% 7% 12% 14% 7% 11% 8% 8% 6% 13%	2220
	21st to end	Day	9% 18% 10% 16% 8% 4 6% 5% 5% 5% 15%	2668
February	1st to 10th	Day	7% 12% 5% 11% 8% 4 9% 7% 8% 7% 21%	1656
	11th to 20th	Day	8% 9% 6% 8% 8% 5% 8% 6% 6% 8% 27%	1574
	21st to end	Day	6% 10% 5% 14% 10% 4 7% 5% 5% 6% 26%	1332
March	1st to 10th	Day	11% 14% 6% 9% 7% 4 5% 5% 5% 6% 27%	1896
	11th to 20th	Day	9% 11% 6% 9% 8% 4 4 5% 6% 7% 32%	1980
	21st to end	Day	12% 12% 5% 8% 7% 4 5% 4 4 6% 32%	2178
April	1st to 10th	Day	13% 13% 4 8% 6% 3 4 4 5% 5% 34%	2170
	11th to 20th	Day	14% 10% 3 7% 6% 3 4 4 5% 7% 35%	2312
	21st to end	Day	16% 10% 4 6% 7% 4 5% 4 6% 7% 31%	2340
May	1st to 10th	Day	16% 9% 5% 5% 6% 3 4 4 5% 7% 37%	2484
	11th to 20th	Day	18% 9% 3 6% 6% 3 4 4 5% 8% 34%	2514
	21st to end	Day	21% 7% 3 5% 5% 3 4 5% 4 7% 37%	2918
June	1st to 10th	Day	15% 6% 3 7% 5% 4 6% 6% 6% 9% 34%	2700
	11th to 20th	Day	18% 6% 3 7% 6% 3 5% 6% 6% 8% 33%	2700
	21st to end	Day	15% 6% 3 7% 6% 3 6% 6% 7% 9% 31%	2700
July	1st to 10th	Day	9% 4 2 5% 5% 3 5% 5% 6% 9% 46%	2700
	11th to 20th	Day	12% 5% 3 5% 5% 4 6% 5% 6% 9% 41%	2700
	21st to end	Day	11% 5% 2 4 5% 4 5% 5% 7% 8% 45%	2939
August	1st to 10th	Day	9% 6% 3 6% 6% 4 5% 5% 7% 9% 40%	2404
	11th to 20th	Day	12% 6% 2 5% 6% 3 5% 5% 6% 9% 42%	2301
	21st to end	Day	15% 6% 2 5% 4 3 4 5% 6% 7% 43%	2574
September	1st to 10th	Day	13% 6% 2 5% 5% 4 4 5% 5% 8% 43%	2201
	11th to 20th	Day	17% 7% 2 7% 7% 4 5% 5% 5% 9% 33%	2040
	21st to end	Day	20% 7% 4 7% 5% 2 4 4 5% 6% 37%	1958
October	1st to 10th	Day	20% 14% 4 6% 6% 3 4 4 5% 6% 29%	1800
	11th to 20th	Day	17% 16% 4 7% 6% 3 4 4 4 7% 29%	1800
	21st to end	Day	17% 19% 5% 9% 7% 3 4 4 4 6% 21%	1779
November	1st to 10th	Day	16% 17% 6% 10% 8% 4 3 5% 4 5% 23%	1487
	11th to 20th	Day	12% 17% 7% 14% 8% 4 4 4 4 5% 21%	1520
	21st to end	Day	13% 15% 7% 13% 12% 4 4 3 4 6% 19%	1493
December	1st to 10th	Day	9% 13% 6% 17% 11% 6% 8% 6% 5% 5% 15%	1330
	11th to 20th	Day	9% 15% 7% 13% 9% 3 5% 5% 7% 8% 19%	1679
	21st to end	Day	13% 12% 6% 12% 8% 4 5% 6% 7% 7% 22%	2442
January	1st to 10th	Night	6% 13% 7% 14% 11% 8% 7% 6% 6% 6% 17%	4737
	11th to 20th	Night	6% 12% 6% 13% 15% 9% 11% 8% 8% 4 10%	4750
	21st to end	Night	9% 19% 9% 12% 8% 5% 6% 5% 6% 5% 16%	4997
February	1st to 10th	Night	7% 12% 5% 8% 8% 5% 7% 7% 8% 8% 25%	2399
	11th to 20th	Night	8% 9% 3 9% 6% 4 8% 8% 7% 7% 32%	2273
	21st to end	Night	6% 10% 5% 12% 9% 5% 6% 7% 6% 5% 29%	1924
March	1st to 10th	Night	8% 13% 6% 10% 8% 4 5% 4 4 6% 31%	2068
	11th to 20th	Night	8% 8% 4 8% 7% 3 4 5% 4 7% 41%	1979
	21st to end	Night	13% 12% 4 8% 4 3 3 4 5% 7% 36%	2178
April	1st to 10th	Night	13% 10% 3 6% 6% 2 6% 5% 5% 6% 39%	1788
	11th to 20th	Night	14% 11% 4 6% 6% 3 4 4 5% 7% 37%	1599
	21st to end	Night	14% 9% 4 6% 6% 4 6% 4 4 6% 37%	1620
May	1st to 10th	Night	16% 9% 4 6% 5% 3 4 5% 5% 7% 37%	1475
	11th to 20th	Night	16% 7% 3 5% 5% 3 5% 4 5% 8% 40%	1380
	21st to end	Night	18% 7% 3 4 5% 2 4 4 5% 8% 41%	1358
June	1st to 10th	Night	14% 7% 3 7% 6% 2 4 5% 6% 8% 38%	1260
	11th to 20th	Night	14% 6% 2 5% 7% 3 5% 4 5% 7% 40%	1260
	21st to end	Night	14% 6% 2 4 4 3 6% 5% 6% 8% 42%	1260
July	1st to 10th	Night	6% 4 2 3 4 2 4 5% 5% 10% 55%	1260
	11th to 20th	Night	9% 4 2 4 4 2 5% 6% 7% 10% 47%	1260
	21st to end	Night	9% 3 1 3 3 3 3 4 6% 8% 57%	1379
August	1st to 10th	Night	7% 3 2 4 5% 3 5% 5% 5% 8% 54%	1532
	11th to 20th	Night	11% 5% 2 4 4 3 4 4 7% 7% 49%	1600
	21st to end	Night	13% 6% 3 4 4 2 4 4 4 8% 50%	1782
September	1st to 10th	Night	13% 5% 2 6% 4 2 3 4 5% 7% 49%	1759
	11th to 20th	Night	16% 7% 2 5% 5% 3 4 4 5% 6% 43%	1916
	21st to end	Night	19% 7% 3 5% 4 2 4 5% 4 8% 39%	1983
October	1st to 10th	Night	16% 12% 3 7% 6% 4 4 4 5% 6% 33%	2160
	11th to 20th	Night	20% 10% 3 8% 6% 3 5% 4 5% 7% 29%	2160
	21st to end	Night	19% 16% 4 8% 5% 3 5% 4 4 5% 26%	2574
November	1st to 10th	Night	14% 16% 7% 9% 7% 3 5% 4 4 6% 25%	2591
	11th to 20th	Night	13% 16% 7% 13% 11% 4 4 4 3 4 21%	2660
	21st to end	Night	13% 15% 7% 13% 10% 5% 5% 4 5% 5% 18%	2683
December	1st to 10th	Night	8% 12% 6% 16% 12% 6% 7% 6% 5% 5% 16%	2850
	11th to 20th	Night	9% 14% 7% 14% 9% 5% 6% 6% 6% 6% 18%	3518
	21st to end	Night	10% 12% 7% 12% 12% 5% 6% 6% 6% 5% 20%	5225

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	64% 6% 10% 16% 4	2219
	11th to 20th	Day	67% 7% 13% 11% 3	2220
	21st to end	Day	70% 5% 9% 12% 4	2668
February	1st to 10th	Day	57% 7% 12% 15% 9% 1	1656
	11th to 20th	Day	53% 7% 12% 19% 9%	1583
	21st to end	Day	58% 7% 10% 15% 10%	1332
March	1st to 10th	Day	57% 6% 12% 17% 8%	1898
	11th to 20th	Day	50% 7% 14% 20% 8% 1	1980
	21st to end	Day	53% 6% 13% 19% 8% 1	2178
April	1st to 10th	Day	51% 4 11% 20% 12% 1	2170
	11th to 20th	Day	48% 6% 10% 22% 12% 2	2312
	21st to end	Day	50% 7% 14% 19% 9% 1	2340
May	1st to 10th	Day	47% 6% 12% 21% 12% 1	2484
	11th to 20th	Day	48% 7% 10% 21% 13% 2	2518
	21st to end	Day	48% 7% 11% 20% 13% 1	2918
June	1st to 10th	Day	45% 9% 15% 20% 10% 1	2700
	11th to 20th	Day	47% 8% 15% 20% 10%	2700
	21st to end	Day	46% 11% 17% 20% 6%	2700
July	1st to 10th	Day	32% 9% 17% 30% 11%	2626
	11th to 20th	Day	37% 10% 17% 28% 9%	2619
	21st to end	Day	35% 9% 19% 27% 9% 1	2776
August	1st to 10th	Day	38% 10% 16% 27% 8% 1	2388
	11th to 20th	Day	37% 9% 20% 28% 6%	2301
	21st to end	Day	39% 9% 15% 29% 7%	2574
September	1st to 10th	Day	39% 8% 16% 28% 8%	2201
	11th to 20th	Day	47% 9% 18% 22% 4	2040
	21st to end	Day	47% 6% 13% 29% 4	1958
October	1st to 10th	Day	56% 8% 15% 17% 5%	1800
	11th to 20th	Day	55% 7% 13% 20% 5%	1800
	21st to end	Day	64% 8% 14% 12% 2	1779
November	1st to 10th	Day	64% 6% 13% 12% 4 1	1487
	11th to 20th	Day	66% 6% 12% 11% 4	1520
	21st to end	Day	67% 6% 15% 10% 2	1493
December	1st to 10th	Day	68% 9% 10% 9% 3	1330
	11th to 20th	Day	62% 6% 15% 13% 3	1680
	21st to end	Day	58% 7% 12% 18% 5%	2442
January	1st to 10th	Night	66% 6% 13% 12% 3	4737
	11th to 20th	Night	71% 7% 9% 10% 3	4750
	21st to end	Night	68% 6% 12% 10% 3	4997
February	1st to 10th	Night	52% 7% 15% 17% 8% 1	2399
	11th to 20th	Night	48% 7% 16% 19% 9%	2274
	21st to end	Night	53% 8% 12% 18% 9%	1924
March	1st to 10th	Night	53% 6% 12% 17% 11% 1	2079
	11th to 20th	Night	44% 6% 14% 23% 13% 1	1980
	21st to end	Night	47% 7% 14% 18% 12% 2	2178
April	1st to 10th	Night	45% 5% 10% 21% 16% 3	1788
	11th to 20th	Night	46% 5% 11% 19% 17% 3	1599
	21st to end	Night	48% 5% 10% 22% 13% 1	1620
May	1st to 10th	Night	45% 7% 11% 22% 14% 1	1475
	11th to 20th	Night	42% 7% 13% 23% 14% 2	1381
	21st to end	Night	42% 6% 13% 21% 16% 2	1358
June	1st to 10th	Night	41% 9% 19% 18% 12% 1	1260
	11th to 20th	Night	42% 7% 13% 22% 15% 2	1260
	21st to end	Night	38% 9% 18% 25% 7% 1	1260
July	1st to 10th	Night	24% 7% 17% 38% 14% 1	1225
	11th to 20th	Night	28% 11% 20% 27% 13% 1	1218
	21st to end	Night	26% 7% 17% 37% 13% 1	1302
August	1st to 10th	Night	28% 7% 19% 35% 11% 1	1524
	11th to 20th	Night	31% 8% 21% 31% 8%	1600
	21st to end	Night	33% 7% 16% 32% 11% 1	1782
September	1st to 10th	Night	35% 6% 17% 31% 11%	1759
	11th to 20th	Night	41% 8% 17% 24% 9% 1	1916
	21st to end	Night	44% 7% 14% 28% 7%	1983
October	1st to 10th	Night	51% 8% 14% 19% 8%	2160
	11th to 20th	Night	55% 7% 13% 21% 4	2160
	21st to end	Night	59% 7% 15% 15% 3	2574
November	1st to 10th	Night	61% 6% 14% 14% 5% 1	2591
	11th to 20th	Night	67% 7% 10% 11% 4	2660
	21st to end	Night	68% 7% 12% 10% 3	2683
December	1st to 10th	Night	68% 7% 13% 8% 2	2850
	11th to 20th	Night	64% 6% 13% 12% 4	3516
	21st to end	Night	62% 9% 11% 14% 5%	5225

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	13% 15% 41% 21% 9% 1	270
	11th to 20th	Day	13% 11% 42% 29% 5% 1	270
	21st to end	Day	18% 14% 37% 22% 6% 2	297
February	1st to 10th	Day	18% 14% 43% 18% 5% 2	252
	11th to 20th	Day	17% 19% 41% 14% 6% 3	240
	21st to end	Day	14% 20% 43% 17% 6% 1	198
March	1st to 10th	Day	11% 18% 44% 19% 7% 1	240
	11th to 20th	Day	17% 17% 40% 17% 8% 2	240
	21st to end	Day	16% 19% 38% 23% 4 1	264
April	1st to 10th	Day	20% 18% 36% 18% 7% 1	430
	11th to 20th	Day	22% 19% 33% 19% 7% 1	590
	21st to end	Day	18% 19% 35% 22% 5% 1	600
May	1st to 10th	Day	20% 20% 34% 20% 4 1	603
	11th to 20th	Day	23% 16% 30% 21% 8% 2	625
	21st to end	Day	22% 14% 31% 25% 7% 1	679
June	1st to 10th	Day	18% 17% 34% 22% 7% 3	630
	11th to 20th	Day	20% 15% 36% 21% 6% 2	630
	21st to end	Day	17% 11% 31% 26% 11% 4	630
July	1st to 10th	Day	11% 14% 34% 25% 12% 4	621
	11th to 20th	Day	14% 15% 30% 26% 14% 2	618
	21st to end	Day	10% 11% 35% 27% 13% 5%	684
August	1st to 10th	Day	10% 11% 31% 30% 14% 3	626
	11th to 20th	Day	13% 9% 33% 26% 14% 5%	615
	21st to end	Day	16% 13% 32% 27% 12% 1	693
September	1st to 10th	Day	15% 14% 34% 27% 9% 1	491
	11th to 20th	Day	18% 19% 37% 20% 6% 1	330
	21st to end	Day	27% 18% 35% 19% 1	270
October	1st to 10th	Day	26% 16% 30% 20% 7% 1	270
	11th to 20th	Day	24% 15% 37% 20% 4	270
	21st to end	Day	32% 19% 30% 16% 3	297
November	1st to 10th	Day	24% 19% 35% 17% 4	270
	11th to 20th	Day	21% 22% 37% 17% 3	270
	21st to end	Day	26% 25% 34% 11% 3	270
December	1st to 10th	Day	16% 13% 40% 23% 7% 1	270
	11th to 20th	Day	20% 19% 44% 14% 3	270
	21st to end	Day	14% 17% 37% 21% 8% 2	297
January	1st to 10th	Night	14% 15% 36% 26% 9% 1	950
	11th to 20th	Night	16% 12% 39% 24% 7% 1	950
	21st to end	Night	15% 13% 38% 26% 7%	1045
February	1st to 10th	Night	12% 12% 37% 32% 7% 1	923
	11th to 20th	Night	13% 12% 37% 26% 10% 2	879
	21st to end	Night	10% 14% 42% 23% 10% 2	740
March	1st to 10th	Night	14% 13% 35% 26% 11% 1	639
	11th to 20th	Night	12% 14% 42% 22% 10% 1	540
	21st to end	Night	20% 13% 26% 26% 13% 2	594
April	1st to 10th	Night	16% 13% 35% 28% 7% 1	540
	11th to 20th	Night	20% 11% 29% 28% 10% 1	533
	21st to end	Night	16% 11% 38% 29% 6%	540
May	1st to 10th	Night	20% 11% 36% 26% 6% 1	540
	11th to 20th	Night	18% 10% 34% 26% 10% 1	531
	21st to end	Night	20% 11% 35% 25% 9% 1	584
June	1st to 10th	Night	17% 10% 30% 30% 13%	540
	11th to 20th	Night	16% 8% 37% 26% 11% 1	540
	21st to end	Night	16% 6% 24% 34% 18% 1	540
July	1st to 10th	Night	7% 5% 30% 39% 18% 1	525
	11th to 20th	Night	10% 7% 30% 37% 16% 1	522
	21st to end	Night	10% 4 27% 37% 19% 3	591
August	1st to 10th	Night	8% 7% 29% 37% 18% 1	537
	11th to 20th	Night	13% 8% 24% 33% 19% 3	534
	21st to end	Night	17% 4 27% 34% 16% 1	594
September	1st to 10th	Night	15% 7% 33% 31% 12% 2	540
	11th to 20th	Night	18% 10% 32% 30% 10%	540
	21st to end	Night	21% 11% 33% 26% 8% 1	543
October	1st to 10th	Night	23% 14% 33% 23% 7%	720
	11th to 20th	Night	26% 11% 32% 24% 7% 1	720
	21st to end	Night	28% 14% 30% 23% 6% 1	947
November	1st to 10th	Night	22% 14% 36% 22% 6% 1	925
	11th to 20th	Night	23% 13% 36% 21% 6% 1	950
	21st to end	Night	23% 17% 38% 17% 4 1	950
December	1st to 10th	Night	14% 13% 38% 28% 7% 1	950
	11th to 20th	Night	17% 17% 40% 19% 5% 1	950
	21st to end	Night	18% 14% 36% 23% 9% 1	1045

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