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 2026-07-01.

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 9% 6% 5% 5% 4 6% 7% 32%	138278
	Night	10% 11% 5% 11% 6% 5% 5% 4 6% 6% 29%	134395
Transparency	Day	48% 7% 14% 22% 9% 1	141686
	Night	52% 6% 13% 20% 8% 1	139084
Seeing	Day	18% 16% 35% 21% 7% 2	18549
	Night	17% 12% 35% 26% 9% 1	28484

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% 14% 8% 19% 7% 7% 7% 4 5% 4 19%	4124
	11th to 20th	Day	4 12% 7% 16% 9% 9% 11% 7% 9% 5% 11%	4112
	21st to end	Day	5% 15% 8% 16% 6% 7% 9% 6% 7% 7% 16%	4964
February	1st to 10th	Day	7% 14% 6% 12% 8% 7% 9% 5% 7% 6% 19%	1890
	11th to 20th	Day	7% 10% 5% 9% 7% 8% 8% 5% 6% 7% 28%	1844
	21st to end	Day	6% 11% 4 16% 9% 6% 7% 4 5% 6% 26%	1557
March	1st to 10th	Day	9% 12% 4 10% 7% 4 4 3 5% 6% 35%	4857
	11th to 20th	Day	9% 10% 5% 14% 9% 5% 4 4 6% 7% 27%	5090
	21st to end	Day	12% 14% 5% 10% 5% 6% 4 2 4 6% 33%	5585
April	1st to 10th	Day	12% 13% 4 10% 5% 4 4 4 6% 5% 33%	2533
	11th to 20th	Day	14% 11% 4 8% 5% 4 4 4 5% 7% 34%	2702
	21st to end	Day	16% 10% 3 8% 6% 5% 4 3 6% 7% 31%	2730
May	1st to 10th	Day	11% 11% 4 6% 4 3 3 3 5% 6% 43%	8121
	11th to 20th	Day	18% 10% 3 7% 4 4 4 3 5% 7% 33%	8335
	21st to end	Day	14% 7% 2 6% 4 4 4 3 5% 7% 45%	9683
June	1st to 10th	Day	15% 7% 3 7% 5% 5% 6% 5% 6% 9% 34%	3150
	11th to 20th	Day	17% 6% 2 8% 5% 5% 6% 4 6% 8% 33%	3150
	21st to end	Day	15% 7% 3 7% 5% 6% 6% 5% 7% 8% 30%	3150
July	1st to 10th	Day	9% 5% 2 7% 5% 5% 6% 5% 7% 10% 40%	6800
	11th to 20th	Day	11% 5% 2 6% 5% 5% 5% 4 6% 9% 41%	6800
	21st to end	Day	10% 5% 2 6% 4 5% 6% 4 7% 9% 41%	7406
August	1st to 10th	Day	9% 7% 2 7% 5% 5% 5% 4 6% 9% 39%	4368
	11th to 20th	Day	11% 5% 2 6% 5% 4 5% 4 6% 9% 41%	4171
	21st to end	Day	15% 7% 2 6% 4 4 4 4 6% 8% 39%	4675
September	1st to 10th	Day	12% 6% 2 6% 5% 5% 4 4 6% 7% 42%	2445
	11th to 20th	Day	17% 7% 2 8% 6% 5% 5% 3 6% 9% 32%	2266
	21st to end	Day	18% 7% 3 7% 4 3 4 3 5% 6% 40%	2175
October	1st to 10th	Day	19% 14% 3 7% 5% 4 4 3 5% 6% 30%	2000
	11th to 20th	Day	18% 16% 4 8% 5% 3 4 3 4 7% 29%	2000
	21st to end	Day	17% 20% 4 10% 6% 4 3 3 4 7% 21%	1975
November	1st to 10th	Day	15% 19% 5% 12% 6% 4 3 3 4 5% 23%	1647
	11th to 20th	Day	12% 20% 6% 14% 6% 5% 3 3 4 4 23%	1680
	21st to end	Day	12% 17% 6% 16% 10% 5% 3 3 4 6% 18%	1649
December	1st to 10th	Day	11% 15% 5% 17% 11% 10% 6% 4 5% 4 11%	2360
	11th to 20th	Day	7% 16% 5% 15% 7% 5% 6% 6% 7% 7% 18%	2709
	21st to end	Day	9% 16% 8% 19% 8% 5% 5% 4 5% 5% 16%	3575
January	1st to 10th	Night	5% 13% 7% 18% 9% 8% 7% 5% 6% 5% 15%	8800
	11th to 20th	Night	5% 14% 6% 13% 10% 9% 11% 9% 9% 4 10%	8803
	21st to end	Night	6% 15% 7% 13% 7% 6% 8% 5% 9% 7% 17%	9235
February	1st to 10th	Night	8% 13% 4 11% 7% 7% 8% 5% 8% 7% 22%	2730
	11th to 20th	Night	7% 9% 4 10% 6% 6% 8% 6% 8% 7% 30%	2663
	21st to end	Night	6% 12% 4 14% 8% 6% 7% 6% 6% 5% 27%	2249
March	1st to 10th	Night	8% 13% 5% 12% 8% 6% 5% 4 5% 6% 29%	5243
	11th to 20th	Night	7% 10% 5% 11% 8% 6% 4 4 5% 8% 33%	5089
	21st to end	Night	13% 14% 5% 11% 5% 4 3 3 4 5% 32%	5588
April	1st to 10th	Night	13% 10% 3 8% 5% 4 5% 4 5% 6% 38%	2084
	11th to 20th	Night	14% 12% 3 7% 5% 4 3 4 5% 6% 36%	1869
	21st to end	Night	14% 10% 3 6% 6% 6% 4 3 4 6% 38%	1890
May	1st to 10th	Night	11% 7% 3 5% 3 4 4 3 5% 7% 48%	4792
	11th to 20th	Night	18% 7% 2 6% 4 4 4 3 5% 7% 40%	4543
	21st to end	Night	12% 7% 2 5% 3 3 4 3 6% 6% 48%	4526
June	1st to 10th	Night	13% 7% 3 7% 4 3 5% 4 6% 9% 38%	1470
	11th to 20th	Night	14% 7% 2 6% 6% 4 5% 3 5% 8% 41%	1470
	21st to end	Night	14% 7% 2 5% 4 5% 5% 4 6% 8% 41%	1470
July	1st to 10th	Night	9% 6% 2 6% 4 4 4 3 5% 9% 49%	3180
	11th to 20th	Night	9% 4 2 5% 3 4 5% 4 8% 11% 45%	3180
	21st to end	Night	8% 4 2 5% 3 4 4 4 7% 10% 48%	3469
August	1st to 10th	Night	7% 4 2 6% 5% 4 6% 5% 7% 9% 46%	2789
	11th to 20th	Night	11% 5% 2 5% 3 4 5% 3 6% 8% 48%	2888
	21st to end	Night	11% 6% 3 6% 4 3 5% 4 6% 9% 44%	3234
September	1st to 10th	Night	12% 5% 2 7% 3 4 3 3 5% 7% 50%	1955
	11th to 20th	Night	16% 7% 2 6% 4 4 4 3 5% 6% 41%	2130
	21st to end	Night	18% 7% 2 6% 4 4 4 3 4 7% 41%	2204
October	1st to 10th	Night	15% 12% 3 8% 5% 4 4 3 5% 7% 34%	2400
	11th to 20th	Night	19% 12% 3 9% 5% 4 5% 3 4 7% 30%	2400
	21st to end	Night	19% 16% 4 10% 4 4 4 3 4 5% 27%	2862
November	1st to 10th	Night	13% 17% 6% 11% 5% 5% 4 3 4 6% 25%	2871
	11th to 20th	Night	13% 18% 5% 14% 8% 5% 4 3 4 4 21%	2940
	21st to end	Night	12% 16% 7% 16% 9% 6% 4 3 4 4 17%	2966
December	1st to 10th	Night	9% 18% 7% 20% 12% 7% 5% 3 3 4 11%	5050
	11th to 20th	Night	8% 13% 6% 15% 9% 6% 6% 7% 7% 6% 17%	5718
	21st to end	Night	8% 14% 8% 20% 10% 6% 5% 4 4 4 16%	7645

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	67% 5% 7% 14% 6%	4125
	11th to 20th	Day	69% 4 9% 14% 5%	4140
	21st to end	Day	67% 4 7% 17% 6%	4964
February	1st to 10th	Day	60% 6% 11% 14% 8% 1	1890
	11th to 20th	Day	53% 7% 12% 20% 8%	1853
	21st to end	Day	58% 6% 11% 14% 10% 1	1557
March	1st to 10th	Day	48% 6% 15% 16% 10% 5%	4859
	11th to 20th	Day	53% 7% 14% 18% 8%	5090
	21st to end	Day	52% 5% 9% 20% 12% 1	5585
April	1st to 10th	Day	51% 5% 10% 21% 12% 1	2533
	11th to 20th	Day	49% 7% 11% 21% 11% 1	2702
	21st to end	Day	50% 7% 13% 20% 9% 1	2730
May	1st to 10th	Day	40% 7% 11% 26% 16% 1	8132
	11th to 20th	Day	48% 7% 10% 23% 12% 1	8339
	21st to end	Day	37% 6% 10% 26% 18% 2	9683
June	1st to 10th	Day	44% 9% 15% 21% 11% 1	3150
	11th to 20th	Day	46% 9% 15% 21% 9%	3150
	21st to end	Day	46% 11% 17% 19% 7%	3150
July	1st to 10th	Day	36% 10% 21% 26% 7% 1	6727
	11th to 20th	Day	36% 9% 20% 31% 5%	6719
	21st to end	Day	37% 9% 20% 29% 5%	7193
August	1st to 10th	Day	38% 9% 16% 26% 11%	4352
	11th to 20th	Day	36% 9% 24% 26% 5%	4210
	21st to end	Day	40% 8% 21% 25% 5%	4674
September	1st to 10th	Day	38% 8% 17% 29% 8%	2445
	11th to 20th	Day	48% 9% 18% 21% 4	2266
	21st to end	Day	45% 6% 14% 30% 5%	2175
October	1st to 10th	Day	44% 7% 16% 27% 6%	3260
	11th to 20th	Day	46% 5% 15% 21% 13%	3240
	21st to end	Day	53% 6% 18% 19% 3	3172
November	1st to 10th	Day	64% 6% 13% 13% 4 1	1647
	11th to 20th	Day	65% 6% 12% 12% 4	1680
	21st to end	Day	68% 6% 14% 10% 2	1649
December	1st to 10th	Day	75% 8% 10% 6% 2	2360
	11th to 20th	Day	62% 5% 12% 14% 6%	2710
	21st to end	Day	68% 6% 8% 15% 4	3575
January	1st to 10th	Night	68% 5% 10% 11% 7%	8800
	11th to 20th	Night	70% 6% 8% 12% 4	8850
	21st to end	Night	61% 6% 9% 17% 7%	9235
February	1st to 10th	Night	56% 7% 14% 16% 7% 1	2730
	11th to 20th	Night	48% 7% 16% 21% 8%	2664
	21st to end	Night	54% 8% 12% 17% 9%	2249
March	1st to 10th	Night	53% 7% 13% 14% 10% 4	5254
	11th to 20th	Night	47% 7% 16% 19% 9% 1	5090
	21st to end	Night	53% 7% 9% 19% 12% 1	5588
April	1st to 10th	Night	45% 6% 10% 21% 15% 3	2084
	11th to 20th	Night	47% 5% 11% 20% 15% 2	1869
	21st to end	Night	47% 5% 10% 23% 13% 1	1890
May	1st to 10th	Night	34% 7% 9% 33% 17%	4800
	11th to 20th	Night	42% 6% 11% 25% 15% 1	4544
	21st to end	Night	34% 6% 10% 26% 20% 3	4526
June	1st to 10th	Night	39% 9% 18% 20% 13% 1	1470
	11th to 20th	Night	41% 7% 14% 24% 14% 1	1470
	21st to end	Night	39% 9% 18% 25% 7% 1	1470
July	1st to 10th	Night	32% 8% 18% 33% 8% 1	3145
	11th to 20th	Night	29% 8% 22% 35% 6%	3138
	21st to end	Night	30% 9% 23% 30% 8% 1	3368
August	1st to 10th	Night	32% 8% 16% 34% 9%	2781
	11th to 20th	Night	31% 8% 25% 31% 5%	2915
	21st to end	Night	35% 8% 22% 29% 7%	3234
September	1st to 10th	Night	34% 6% 18% 31% 11%	1955
	11th to 20th	Night	42% 8% 17% 24% 8% 1	2130
	21st to end	Night	42% 7% 14% 28% 8%	2204
October	1st to 10th	Night	42% 6% 13% 29% 10%	3920
	11th to 20th	Night	47% 5% 15% 25% 8%	3899
	21st to end	Night	53% 6% 14% 22% 5%	4624
November	1st to 10th	Night	60% 6% 13% 14% 6% 1	2871
	11th to 20th	Night	66% 6% 10% 12% 4	2940
	21st to end	Night	70% 7% 11% 9% 3	2966
December	1st to 10th	Night	77% 5% 9% 6% 2	5050
	11th to 20th	Night	64% 5% 11% 11% 9%	5716
	21st to end	Night	69% 7% 8% 13% 4	7645

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% 18% 41% 20% 9% 1	330
	11th to 20th	Day	13% 12% 43% 26% 5% 1	330
	21st to end	Day	18% 17% 39% 19% 6% 2	363
February	1st to 10th	Day	21% 19% 37% 19% 4 1	330
	11th to 20th	Day	15% 17% 39% 19% 7% 2	330
	21st to end	Day	15% 22% 42% 15% 5% 1	273
March	1st to 10th	Day	16% 19% 40% 18% 5% 1	330
	11th to 20th	Day	18% 20% 40% 14% 6% 2	330
	21st to end	Day	18% 20% 38% 19% 4 1	363
April	1st to 10th	Day	19% 18% 38% 17% 7% 1	553
	11th to 20th	Day	23% 20% 33% 19% 5%	740
	21st to end	Day	20% 19% 33% 21% 6% 1	750
May	1st to 10th	Day	19% 21% 34% 21% 4 1	753
	11th to 20th	Day	24% 18% 31% 19% 6% 2	775
	21st to end	Day	21% 13% 32% 25% 7% 1	844
June	1st to 10th	Day	18% 18% 34% 21% 7% 2	780
	11th to 20th	Day	19% 16% 37% 21% 5% 2	780
	21st to end	Day	18% 12% 32% 24% 10% 3	780
July	1st to 10th	Day	11% 13% 34% 24% 13% 5%	722
	11th to 20th	Day	14% 15% 31% 25% 14% 2	718
	21st to end	Day	9% 11% 36% 27% 12% 4	794
August	1st to 10th	Day	11% 11% 32% 30% 13% 3	726
	11th to 20th	Day	13% 8% 33% 26% 14% 4	715
	21st to end	Day	16% 13% 33% 26% 11% 1	803
September	1st to 10th	Day	15% 14% 34% 27% 9% 2	575
	11th to 20th	Day	19% 18% 38% 19% 5% 1	396
	21st to end	Day	24% 18% 36% 19% 3	330
October	1st to 10th	Day	25% 17% 32% 20% 6% 1	330
	11th to 20th	Day	27% 17% 34% 18% 3	330
	21st to end	Day	32% 18% 29% 17% 3	363
November	1st to 10th	Day	26% 19% 34% 16% 5% 1	330
	11th to 20th	Day	23% 23% 35% 15% 4	330
	21st to end	Day	25% 24% 36% 13% 2	330
December	1st to 10th	Day	18% 14% 39% 21% 6% 1	330
	11th to 20th	Day	21% 19% 44% 13% 2	330
	21st to end	Day	13% 20% 37% 20% 9% 2	363
January	1st to 10th	Night	13% 16% 37% 25% 9% 1	1050
	11th to 20th	Night	16% 12% 40% 24% 7% 1	1050
	21st to end	Night	14% 15% 39% 25% 6%	1155
February	1st to 10th	Night	14% 13% 36% 30% 6%	1050
	11th to 20th	Night	12% 12% 37% 26% 10% 2	1029
	21st to end	Night	11% 15% 41% 22% 9% 1	865
March	1st to 10th	Night	14% 14% 36% 25% 9% 1	743
	11th to 20th	Night	11% 15% 44% 21% 8% 1	630
	21st to end	Night	20% 13% 29% 24% 11% 2	693
April	1st to 10th	Night	16% 12% 36% 29% 7% 1	630
	11th to 20th	Night	21% 12% 30% 28% 9% 1	623
	21st to end	Night	16% 12% 37% 28% 6%	630
May	1st to 10th	Night	18% 12% 36% 26% 7%	630
	11th to 20th	Night	19% 12% 34% 26% 8% 1	621
	21st to end	Night	19% 11% 33% 27% 9%	683
June	1st to 10th	Night	17% 11% 32% 29% 12%	630
	11th to 20th	Night	17% 9% 37% 26% 10% 1	630
	21st to end	Night	17% 7% 25% 33% 16% 1	630
July	1st to 10th	Night	7% 5% 30% 38% 19% 1	585
	11th to 20th	Night	10% 7% 30% 37% 16% 1	582
	21st to end	Night	10% 5% 27% 38% 18% 3	657
August	1st to 10th	Night	8% 8% 28% 38% 18% 1	597
	11th to 20th	Night	13% 8% 24% 32% 20% 3	594
	21st to end	Night	16% 6% 28% 34% 15% 1	660
September	1st to 10th	Night	15% 7% 33% 32% 12% 2	600
	11th to 20th	Night	18% 11% 32% 30% 10%	600
	21st to end	Night	20% 11% 33% 26% 9% 2	604
October	1st to 10th	Night	22% 15% 34% 23% 6%	800
	11th to 20th	Night	27% 11% 33% 23% 7% 1	800
	21st to end	Night	27% 13% 31% 22% 6% 1	1053
November	1st to 10th	Night	22% 15% 35% 22% 6% 1	1025
	11th to 20th	Night	24% 14% 35% 20% 6% 1	1050
	21st to end	Night	22% 18% 38% 17% 4 1	1050
December	1st to 10th	Night	14% 14% 38% 27% 6% 1	1050
	11th to 20th	Night	18% 18% 41% 18% 4 1	1050
	21st to end	Night	18% 15% 36% 23% 8% 1	1155

Page generated at 2026-06-28 01:10:44. Version ac07

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