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 2025-02-25.

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% 10% 4 10% 6% 5% 5% 4 6% 7% 31%	108359
	Night	10% 12% 5% 11% 7% 5% 5% 4 6% 6% 28%	110506
Transparency	Day	49% 7% 14% 21% 7%	111817
	Night	53% 7% 13% 19% 8%	115218
Seeing	Day	18% 16% 35% 22% 8% 2	16591
	Night	17% 12% 34% 26% 9% 1	26716

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	5% 14% 9% 17% 6% 7% 7% 5% 6% 4 20%	3178
	11th to 20th	Day	4 11% 7% 16% 10% 8% 9% 7% 12% 6% 11%	3152
	21st to end	Day	6% 19% 10% 18% 7% 6% 6% 3 5% 5% 15%	3835
February	1st to 10th	Day	7% 13% 5% 12% 8% 7% 9% 5% 8% 7% 20%	1800
	11th to 20th	Day	7% 10% 4 9% 7% 8% 8% 5% 6% 7% 27%	1754
	21st to end	Day	6% 12% 4 16% 8% 6% 7% 4 5% 6% 26%	1449
March	1st to 10th	Day	10% 12% 4 11% 10% 5% 5% 3 5% 6% 29%	3304
	11th to 20th	Day	7% 10% 5% 16% 10% 4 4 4 6% 7% 27%	3480
	21st to end	Day	11% 16% 6% 9% 5% 5% 4 2 4 5% 33%	3814
April	1st to 10th	Day	12% 14% 4 9% 5% 4 4 4 6% 5% 34%	2292
	11th to 20th	Day	14% 11% 4 8% 5% 5% 4 4 5% 7% 34%	2442
	21st to end	Day	16% 11% 4 7% 6% 5% 4 3 6% 7% 31%	2470
May	1st to 10th	Day	17% 10% 4 6% 4 4 4 4 5% 7% 35%	4364
	11th to 20th	Day	21% 10% 3 8% 5% 3 4 3 5% 6% 32%	4460
	21st to end	Day	22% 11% 3 7% 4 3 3 3 4 5% 35%	5173
June	1st to 10th	Day	15% 7% 3 7% 5% 5% 6% 5% 6% 8% 34%	2850
	11th to 20th	Day	18% 6% 2 8% 5% 4 6% 4 6% 8% 33%	2850
	21st to end	Day	15% 7% 3 7% 5% 5% 6% 5% 7% 9% 31%	2850
July	1st to 10th	Day	10% 5% 2 7% 5% 6% 6% 5% 7% 9% 37%	4750
	11th to 20th	Day	10% 4 2 5% 4 5% 5% 4 6% 9% 47%	4750
	21st to end	Day	9% 5% 2 6% 4 5% 6% 4 7% 8% 44%	5151
August	1st to 10th	Day	9% 7% 2 7% 5% 5% 5% 4 6% 10% 39%	4234
	11th to 20th	Day	11% 5% 2 6% 5% 4 5% 4 6% 9% 42%	4041
	21st to end	Day	16% 7% 2 6% 4 4 4 4 6% 8% 39%	4532
September	1st to 10th	Day	12% 6% 2 6% 4 5% 4 4 5% 8% 43%	2323
	11th to 20th	Day	17% 7% 2 8% 6% 5% 5% 4 6% 9% 33%	2153
	21st to end	Day	19% 7% 4 7% 4 3 4 3 5% 6% 38%	2066
October	1st to 10th	Day	19% 14% 3 7% 5% 4 4 3 5% 6% 30%	1900
	11th to 20th	Day	17% 15% 4 8% 4 3 4 3 4 7% 30%	1900
	21st to end	Day	17% 20% 5% 10% 6% 5% 3 3 4 7% 21%	1877
November	1st to 10th	Day	16% 19% 5% 12% 6% 4 3 3 4 5% 23%	1567
	11th to 20th	Day	13% 20% 5% 14% 6% 6% 3 3 4 4 21%	1600
	21st to end	Day	13% 18% 6% 15% 10% 5% 3 3 4 5% 18%	1571
December	1st to 10th	Day	11% 15% 5% 17% 11% 10% 6% 4 5% 5% 11%	2290
	11th to 20th	Day	8% 15% 5% 15% 7% 5% 6% 6% 8% 7% 19%	2639
	21st to end	Day	9% 16% 8% 19% 8% 5% 5% 3 5% 5% 17%	3498
January	1st to 10th	Night	5% 14% 6% 17% 9% 9% 7% 5% 6% 5% 16%	6787
	11th to 20th	Night	5% 13% 6% 13% 10% 10% 11% 8% 10% 4 9%	6753
	21st to end	Night	7% 19% 9% 15% 7% 6% 6% 4 7% 5% 15%	7141
February	1st to 10th	Night	8% 13% 4 10% 7% 7% 8% 6% 8% 7% 23%	2600
	11th to 20th	Night	7% 9% 4 10% 5% 6% 8% 6% 8% 7% 30%	2533
	21st to end	Night	6% 11% 4 13% 8% 6% 7% 5% 6% 5% 29%	2100
March	1st to 10th	Night	10% 12% 4 11% 8% 6% 6% 4 4 6% 29%	3558
	11th to 20th	Night	6% 9% 5% 11% 7% 4 4 4 5% 8% 37%	3479
	21st to end	Night	12% 16% 4 10% 4 4 3 3 4 6% 33%	3817
April	1st to 10th	Night	13% 10% 3 7% 5% 4 5% 4 5% 6% 40%	1886
	11th to 20th	Night	14% 12% 3 7% 5% 4 3 4 5% 6% 36%	1689
	21st to end	Night	14% 10% 3 6% 6% 6% 5% 3 4 6% 37%	1710
May	1st to 10th	Night	18% 10% 3 6% 4 4 3 3 5% 7% 36%	2572
	11th to 20th	Night	20% 7% 2 6% 4 4 4 3 5% 7% 38%	2431
	21st to end	Night	20% 11% 2 6% 3 3 3 3 5% 6% 39%	2414
June	1st to 10th	Night	14% 7% 3 8% 4 3 5% 4 6% 9% 38%	1330
	11th to 20th	Night	15% 7% 2 6% 6% 4 5% 4 6% 7% 40%	1330
	21st to end	Night	14% 7% 2 5% 4 5% 5% 4 6% 8% 42%	1330
July	1st to 10th	Night	9% 5% 2 5% 3 4 4 4 6% 10% 49%	2220
	11th to 20th	Night	6% 4 1 4 3 4 4 4 7% 11% 53%	2220
	21st to end	Night	7% 3 2 5% 3 4 4 4 7% 10% 52%	2414
August	1st to 10th	Night	7% 4 2 6% 5% 4 6% 5% 7% 9% 46%	2703
	11th to 20th	Night	11% 5% 2 5% 3 4 5% 3 6% 8% 49%	2798
	21st to end	Night	11% 6% 3 6% 4 3 5% 4 6% 9% 44%	3135
September	1st to 10th	Night	13% 5% 2 7% 3 3 3 3 5% 7% 50%	1857
	11th to 20th	Night	16% 7% 2 6% 4 4 4 3 5% 6% 42%	2023
	21st to end	Night	19% 7% 2 6% 4 4 4 3 4 7% 40%	2094
October	1st to 10th	Night	16% 12% 3 8% 5% 4 4 3 4 7% 34%	2280
	11th to 20th	Night	19% 11% 3 9% 5% 4 5% 3 4 7% 30%	2280
	21st to end	Night	18% 16% 4 9% 4 4 4 3 4 5% 27%	2718
November	1st to 10th	Night	13% 18% 6% 10% 6% 5% 5% 3 4 6% 25%	2731
	11th to 20th	Night	13% 18% 6% 15% 8% 5% 4 3 4 4 20%	2800
	21st to end	Night	13% 17% 7% 16% 9% 6% 4 3 4 4 17%	2825
December	1st to 10th	Night	9% 19% 7% 20% 12% 7% 4 3 3 4 11%	4900
	11th to 20th	Night	8% 14% 6% 16% 9% 6% 6% 7% 7% 6% 17%	5568
	21st to end	Night	8% 14% 8% 20% 10% 6% 5% 4 5% 4 16%	7480

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	65% 5% 8% 14% 8%	3179
	11th to 20th	Day	65% 5% 10% 16% 4	3180
	21st to end	Day	71% 4 9% 12% 3	3835
February	1st to 10th	Day	59% 6% 12% 14% 8% 1	1800
	11th to 20th	Day	53% 7% 13% 20% 8%	1763
	21st to end	Day	57% 7% 11% 14% 10% 1	1449
March	1st to 10th	Day	53% 7% 13% 19% 7%	3306
	11th to 20th	Day	52% 9% 15% 17% 6%	3480
	21st to end	Day	53% 6% 11% 21% 9% 1	3814
April	1st to 10th	Day	50% 4 11% 21% 13% 1	2292
	11th to 20th	Day	48% 7% 10% 22% 12% 2	2442
	21st to end	Day	49% 7% 14% 20% 8% 1	2470
May	1st to 10th	Day	44% 9% 13% 22% 10% 1	4376
	11th to 20th	Day	49% 9% 11% 18% 12% 1	4464
	21st to end	Day	51% 7% 10% 23% 9% 1	5173
June	1st to 10th	Day	45% 9% 15% 20% 11% 1	2850
	11th to 20th	Day	46% 8% 15% 20% 10%	2850
	21st to end	Day	46% 11% 17% 19% 7%	2850
July	1st to 10th	Day	38% 11% 20% 24% 7%	4676
	11th to 20th	Day	30% 9% 22% 33% 7%	4669
	21st to end	Day	34% 9% 19% 31% 6%	4988
August	1st to 10th	Day	39% 9% 15% 26% 11%	4218
	11th to 20th	Day	35% 9% 24% 26% 6%	4080
	21st to end	Day	40% 8% 21% 25% 5%	4531
September	1st to 10th	Day	37% 8% 17% 29% 8%	2323
	11th to 20th	Day	47% 9% 18% 22% 4	2153
	21st to end	Day	46% 6% 13% 29% 5%	2066
October	1st to 10th	Day	44% 7% 16% 27% 6%	3160
	11th to 20th	Day	45% 5% 15% 21% 13%	3140
	21st to end	Day	53% 6% 18% 19% 3	3074
November	1st to 10th	Day	64% 6% 13% 12% 4 1	1567
	11th to 20th	Day	66% 6% 12% 12% 4	1600
	21st to end	Day	68% 6% 14% 10% 2	1571
December	1st to 10th	Day	75% 8% 10% 6% 2	2290
	11th to 20th	Day	61% 5% 13% 14% 7%	2640
	21st to end	Day	68% 6% 8% 15% 4	3498
January	1st to 10th	Night	66% 5% 10% 10% 9%	6787
	11th to 20th	Night	69% 6% 8% 13% 4	6800
	21st to end	Night	68% 6% 10% 11% 5%	7141
February	1st to 10th	Night	55% 7% 14% 16% 7% 1	2600
	11th to 20th	Night	47% 7% 16% 21% 9%	2534
	21st to end	Night	53% 8% 12% 18% 9%	2100
March	1st to 10th	Night	52% 9% 12% 17% 10% 1	3569
	11th to 20th	Night	42% 9% 20% 20% 9% 1	3480
	21st to end	Night	51% 7% 10% 20% 10% 1	3817
April	1st to 10th	Night	44% 6% 10% 21% 16% 3	1886
	11th to 20th	Night	47% 5% 11% 19% 16% 2	1689
	21st to end	Night	48% 6% 10% 22% 13% 1	1710
May	1st to 10th	Night	45% 8% 9% 24% 13%	2579
	11th to 20th	Night	43% 9% 13% 24% 9% 2	2432
	21st to end	Night	45% 7% 12% 24% 11% 1	2414
June	1st to 10th	Night	40% 9% 19% 18% 13% 1	1330
	11th to 20th	Night	42% 7% 13% 22% 14% 1	1330
	21st to end	Night	38% 9% 18% 25% 8% 1	1330
July	1st to 10th	Night	29% 9% 20% 32% 8% 1	2185
	11th to 20th	Night	22% 9% 23% 38% 8% 1	2178
	21st to end	Night	26% 8% 22% 35% 8% 1	2337
August	1st to 10th	Night	32% 8% 16% 34% 9%	2695
	11th to 20th	Night	30% 8% 25% 31% 5%	2825
	21st to end	Night	35% 7% 22% 29% 7%	3135
September	1st to 10th	Night	34% 6% 18% 31% 11%	1857
	11th to 20th	Night	42% 8% 17% 24% 9% 1	2023
	21st to end	Night	43% 7% 13% 28% 8%	2094
October	1st to 10th	Night	42% 6% 13% 30% 9%	3800
	11th to 20th	Night	46% 5% 15% 25% 8%	3779
	21st to end	Night	52% 6% 14% 22% 5%	4480
November	1st to 10th	Night	60% 6% 14% 14% 5% 1	2731
	11th to 20th	Night	68% 7% 10% 11% 4	2800
	21st to end	Night	70% 7% 11% 9% 3	2825
December	1st to 10th	Night	77% 5% 10% 6% 2	4900
	11th to 20th	Night	64% 5% 11% 11% 9%	5566
	21st to end	Night	68% 7% 8% 13% 4	7480

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	12% 16% 41% 21% 10% 1	300
	11th to 20th	Day	13% 11% 42% 28% 5% 1	300
	21st to end	Day	19% 16% 36% 20% 6% 2	330
February	1st to 10th	Day	19% 18% 38% 19% 4 1	300
	11th to 20th	Day	15% 18% 40% 18% 7% 2	300
	21st to end	Day	16% 21% 41% 16% 5% 1	237
March	1st to 10th	Day	13% 19% 41% 19% 7% 1	270
	11th to 20th	Day	17% 19% 39% 16% 7% 2	270
	21st to end	Day	15% 20% 38% 22% 4 1	297
April	1st to 10th	Day	18% 17% 38% 18% 7% 1	472
	11th to 20th	Day	23% 20% 32% 19% 6%	640
	21st to end	Day	19% 19% 35% 22% 5% 1	650
May	1st to 10th	Day	20% 20% 34% 20% 4 2	653
	11th to 20th	Day	23% 17% 30% 20% 7% 2	675
	21st to end	Day	23% 14% 31% 25% 6% 1	734
June	1st to 10th	Day	18% 18% 33% 21% 7% 2	680
	11th to 20th	Day	20% 16% 36% 21% 6% 2	680
	21st to end	Day	18% 11% 32% 25% 11% 4	680
July	1st to 10th	Day	12% 13% 32% 25% 13% 5%	671
	11th to 20th	Day	14% 14% 29% 26% 15% 2	668
	21st to end	Day	9% 11% 35% 27% 12% 5%	739
August	1st to 10th	Day	11% 11% 32% 30% 13% 3	676
	11th to 20th	Day	12% 8% 32% 27% 15% 5%	665
	21st to end	Day	16% 13% 33% 26% 11% 1	748
September	1st to 10th	Day	15% 14% 35% 27% 8% 1	533
	11th to 20th	Day	18% 19% 37% 20% 5% 1	363
	21st to end	Day	26% 18% 35% 19% 2	300
October	1st to 10th	Day	26% 16% 30% 20% 7% 1	300
	11th to 20th	Day	24% 17% 37% 19% 4	300
	21st to end	Day	31% 19% 30% 16% 3	330
November	1st to 10th	Day	24% 19% 34% 17% 5% 1	300
	11th to 20th	Day	23% 22% 37% 15% 3	300
	21st to end	Day	26% 25% 33% 12% 3	300
December	1st to 10th	Day	17% 14% 40% 22% 7% 1	300
	11th to 20th	Day	20% 18% 46% 13% 3	300
	21st to end	Day	13% 18% 36% 21% 10% 2	330
January	1st to 10th	Night	13% 15% 36% 25% 9% 1	1000
	11th to 20th	Night	16% 12% 39% 25% 7% 1	1000
	21st to end	Night	15% 14% 38% 25% 6%	1100
February	1st to 10th	Night	13% 12% 37% 31% 7% 1	1000
	11th to 20th	Night	12% 12% 38% 26% 10% 2	979
	21st to end	Night	10% 15% 41% 23% 10% 1	808
March	1st to 10th	Night	14% 13% 35% 26% 10% 1	673
	11th to 20th	Night	12% 14% 42% 22% 9% 1	570
	21st to end	Night	20% 13% 27% 25% 12% 2	627
April	1st to 10th	Night	15% 12% 36% 29% 7% 1	570
	11th to 20th	Night	21% 12% 30% 27% 10% 1	563
	21st to end	Night	16% 11% 38% 29% 6%	570
May	1st to 10th	Night	20% 12% 36% 26% 6% 1	570
	11th to 20th	Night	18% 11% 34% 26% 9% 1	561
	21st to end	Night	20% 11% 34% 25% 9%	617
June	1st to 10th	Night	17% 11% 30% 30% 12%	570
	11th to 20th	Night	17% 9% 37% 25% 11% 1	570
	21st to end	Night	17% 7% 24% 34% 17% 1	570
July	1st to 10th	Night	7% 5% 30% 38% 19% 1	555
	11th to 20th	Night	9% 7% 30% 37% 17% 1	552
	21st to end	Night	10% 5% 27% 37% 18% 3	624
August	1st to 10th	Night	8% 7% 28% 38% 18% 1	567
	11th to 20th	Night	13% 8% 23% 32% 20% 3	564
	21st to end	Night	16% 5% 28% 34% 15% 1	627
September	1st to 10th	Night	15% 7% 32% 32% 12% 2	570
	11th to 20th	Night	18% 10% 32% 30% 10%	570
	21st to end	Night	20% 11% 34% 26% 8% 1	574
October	1st to 10th	Night	23% 14% 34% 23% 6%	760
	11th to 20th	Night	25% 11% 33% 23% 7% 1	760
	21st to end	Night	27% 13% 31% 22% 6% 1	1000
November	1st to 10th	Night	21% 14% 36% 22% 6% 1	975
	11th to 20th	Night	24% 13% 36% 21% 6% 1	1000
	21st to end	Night	23% 18% 38% 17% 4 1	1000
December	1st to 10th	Night	15% 14% 37% 27% 6% 1	1000
	11th to 20th	Night	17% 18% 41% 19% 5% 1	1000
	21st to end	Night	18% 13% 36% 23% 9% 1	1100

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