St. Malo Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the St. Malo Provincial Park clear sky chart from 2005-11-06 to 2025-10-04.

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	11% 9% 3 9% 5% 5% 5% 4 6% 8% 35%	130661
	Night	9% 10% 4 10% 6% 5% 5% 4 6% 7% 33%	127501
Transparency	Day	48% 4 15% 24% 9% 1	130360
	Night	50% 4 13% 23% 9% 1	127383
Seeing	Day	15% 9% 31% 28% 14% 4	17535
	Night	15% 7% 32% 33% 12% 1	27366

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	5% 15% 6% 15% 7% 6% 7% 7% 6% 9% 18%	3179
	11th to 20th	Day	4 11% 5% 14% 9% 11% 10% 11% 8% 7% 10%	3185
	21st to end	Day	7% 15% 8% 17% 9% 6% 8% 4 5% 6% 14%	4004
February	1st to 10th	Day	8% 14% 6% 13% 8% 6% 8% 6% 7% 6% 19%	1745
	11th to 20th	Day	7% 8% 4 9% 8% 9% 7% 8% 8% 8% 24%	1754
	21st to end	Day	6% 10% 4 13% 9% 9% 7% 5% 6% 7% 24%	1563
March	1st to 10th	Day	9% 10% 4 9% 10% 5% 5% 5% 6% 8% 30%	4632
	11th to 20th	Day	8% 10% 5% 15% 9% 7% 5% 4 6% 8% 22%	4978
	21st to end	Day	10% 14% 6% 11% 6% 5% 5% 4 6% 6% 27%	5464
April	1st to 10th	Day	10% 13% 4 9% 6% 4 4 4 5% 7% 34%	2420
	11th to 20th	Day	14% 10% 4 8% 6% 5% 5% 4 7% 6% 33%	2572
	21st to end	Day	19% 9% 4 7% 5% 4 3 4 5% 7% 33%	2600
May	1st to 10th	Day	12% 8% 2 6% 4 4 4 3 6% 6% 44%	6075
	11th to 20th	Day	17% 9% 3 6% 4 5% 4 4 6% 8% 34%	6534
	21st to end	Day	14% 7% 2 6% 3 4 4 3 5% 6% 45%	7428
June	1st to 10th	Day	13% 7% 2 7% 5% 5% 4 4 7% 9% 37%	3000
	11th to 20th	Day	14% 7% 2 6% 5% 5% 4 4 7% 8% 38%	3000
	21st to end	Day	13% 6% 2 6% 5% 5% 6% 5% 7% 8% 36%	3000
July	1st to 10th	Day	8% 4 2 5% 4 5% 5% 5% 7% 10% 46%	6800
	11th to 20th	Day	10% 5% 2 6% 4 5% 5% 4 6% 9% 45%	6800
	21st to end	Day	8% 5% 2 6% 4 5% 5% 4 6% 9% 46%	7278
August	1st to 10th	Day	9% 5% 2 6% 4 4 5% 4 6% 9% 46%	4344
	11th to 20th	Day	11% 5% 2 5% 4 4 4 4 5% 8% 46%	4171
	21st to end	Day	12% 5% 2 5% 3 4 3 4 5% 9% 48%	4675
September	1st to 10th	Day	11% 5% 2 5% 4 4 4 4 6% 7% 48%	2473
	11th to 20th	Day	15% 6% 2 6% 3 4 5% 4 7% 9% 39%	2200
	21st to end	Day	15% 6% 3 5% 4 3 4 3 6% 8% 43%	2200
October	1st to 10th	Day	12% 7% 2 7% 4 4 4 4 5% 6% 47%	3235
	11th to 20th	Day	12% 10% 3 7% 4 4 4 3 5% 9% 41%	3115
	21st to end	Day	14% 11% 3 8% 5% 4 5% 3 5% 8% 34%	3091
November	1st to 10th	Day	14% 16% 5% 10% 5% 5% 4 3 4 6% 29%	1600
	11th to 20th	Day	11% 16% 6% 13% 7% 4 4 3 5% 5% 25%	1600
	21st to end	Day	13% 14% 5% 12% 8% 7% 6% 4 4 4 23%	1519
December	1st to 10th	Day	9% 16% 6% 13% 11% 9% 6% 5% 5% 5% 14%	2290
	11th to 20th	Day	8% 15% 5% 13% 6% 5% 5% 4 8% 10% 20%	2639
	21st to end	Day	8% 15% 6% 20% 9% 6% 7% 5% 6% 6% 12%	3498
January	1st to 10th	Night	4 12% 7% 16% 8% 9% 8% 6% 7% 8% 16%	6787
	11th to 20th	Night	4 13% 6% 13% 9% 9% 10% 8% 8% 6% 13%	6731
	21st to end	Night	7% 19% 8% 15% 6% 6% 5% 5% 6% 6% 19%	6974
February	1st to 10th	Night	8% 12% 5% 11% 8% 8% 7% 6% 5% 6% 25%	2653
	11th to 20th	Night	7% 8% 3 8% 7% 6% 6% 6% 8% 8% 32%	2533
	21st to end	Night	7% 11% 4 14% 8% 6% 6% 4 5% 6% 30%	2085
March	1st to 10th	Night	8% 11% 4 9% 7% 5% 5% 4 6% 8% 32%	5236
	11th to 20th	Night	7% 12% 4 9% 6% 5% 5% 4 6% 8% 34%	4980
	21st to end	Night	12% 13% 4 12% 5% 4 4 3 5% 6% 33%	5467
April	1st to 10th	Night	11% 9% 2 6% 5% 5% 5% 5% 6% 7% 40%	1975
	11th to 20th	Night	13% 12% 4 8% 5% 5% 4 4 5% 4 36%	1779
	21st to end	Night	14% 9% 3 7% 5% 5% 5% 4 5% 6% 37%	1800
May	1st to 10th	Night	13% 7% 3 6% 4 4 3 3 5% 7% 45%	3903
	11th to 20th	Night	15% 9% 3 8% 4 4 3 3 6% 8% 37%	3381
	21st to end	Night	13% 7% 2 5% 3 2 3 4 5% 7% 49%	3470
June	1st to 10th	Night	12% 5% 2 5% 4 4 5% 4 6% 9% 45%	1400
	11th to 20th	Night	12% 5% 1 5% 5% 4 4 3 6% 9% 44%	1400
	21st to end	Night	10% 4 2 5% 7% 6% 5% 3 7% 9% 42%	1400
July	1st to 10th	Night	7% 3 2 5% 3 4 5% 4 7% 9% 50%	3180
	11th to 20th	Night	6% 3 2 5% 3 4 4 5% 6% 8% 54%	3180
	21st to end	Night	6% 4 2 5% 4 4 5% 4 8% 10% 48%	3572
August	1st to 10th	Night	5% 4 2 7% 5% 4 5% 4 6% 9% 50%	2816
	11th to 20th	Night	11% 4 2 5% 3 3 5% 5% 6% 10% 47%	2888
	21st to end	Night	9% 5% 2 6% 4 4 4 3 5% 8% 48%	3234
September	1st to 10th	Night	9% 4 2 5% 3 3 5% 4 5% 7% 53%	1922
	11th to 20th	Night	13% 6% 2 5% 3 4 4 4 5% 8% 46%	2200
	21st to end	Night	15% 6% 2 5% 4 4 4 3 6% 7% 45%	2200
October	1st to 10th	Night	15% 7% 2 5% 3 3 3 3 4 6% 47%	3758
	11th to 20th	Night	11% 9% 2 7% 5% 4 4 3 5% 7% 43%	3804
	21st to end	Night	10% 10% 4 9% 5% 4 5% 4 5% 6% 39%	4467
November	1st to 10th	Night	13% 14% 4 10% 5% 4 4 4 5% 6% 30%	2698
	11th to 20th	Night	11% 16% 6% 11% 7% 5% 4 4 5% 5% 26%	2800
	21st to end	Night	12% 14% 5% 14% 7% 6% 5% 3 4 5% 25%	2880
December	1st to 10th	Night	7% 16% 6% 16% 13% 8% 6% 4 5% 5% 13%	4900
	11th to 20th	Night	7% 15% 5% 14% 9% 6% 5% 4 7% 7% 22%	5568
	21st to end	Night	8% 13% 5% 19% 9% 8% 5% 3 6% 5% 17%	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	63% 3 10% 17% 7%	3179
	11th to 20th	Day	68% 4 9% 14% 5%	3206
	21st to end	Day	71% 3 9% 14% 4	4004
February	1st to 10th	Day	62% 4 13% 13% 7% 1	1745
	11th to 20th	Day	52% 5% 13% 21% 9%	1763
	21st to end	Day	58% 4 14% 16% 8%	1563
March	1st to 10th	Day	52% 4 16% 17% 10%	4632
	11th to 20th	Day	60% 3 15% 16% 6%	4980
	21st to end	Day	57% 4 10% 22% 7%	5464
April	1st to 10th	Day	49% 4 10% 25% 11% 1	2420
	11th to 20th	Day	51% 4 11% 23% 11% 1	2572
	21st to end	Day	51% 4 15% 21% 8% 2	2600
May	1st to 10th	Day	40% 3 12% 26% 18% 1	6075
	11th to 20th	Day	48% 3 10% 27% 11%	6538
	21st to end	Day	40% 3 8% 27% 19% 4	7428
June	1st to 10th	Day	43% 4 17% 26% 10%	3000
	11th to 20th	Day	43% 5% 17% 25% 9% 1	3000
	21st to end	Day	43% 6% 20% 24% 6%	3000
July	1st to 10th	Day	33% 5% 27% 29% 6%	6726
	11th to 20th	Day	37% 3 22% 32% 6%	6719
	21st to end	Day	35% 4 22% 31% 7%	7073
August	1st to 10th	Day	34% 4 19% 31% 10%	4328
	11th to 20th	Day	36% 4 20% 35% 5%	4210
	21st to end	Day	34% 3 24% 31% 7%	4674
September	1st to 10th	Day	35% 4 18% 32% 11% 1	2473
	11th to 20th	Day	43% 5% 21% 26% 5% 1	2200
	21st to end	Day	40% 5% 16% 32% 7%	2200
October	1st to 10th	Day	40% 3 15% 30% 12%	3235
	11th to 20th	Day	42% 3 12% 28% 15%	3115
	21st to end	Day	51% 3 14% 25% 7%	3091
November	1st to 10th	Day	58% 3 15% 18% 4 1	1600
	11th to 20th	Day	62% 5% 14% 15% 4	1600
	21st to end	Day	65% 4 14% 14% 3	1519
December	1st to 10th	Day	71% 6% 12% 9% 3	2290
	11th to 20th	Day	59% 3 14% 15% 9%	2640
	21st to end	Day	73% 3 5% 14% 4	3498
January	1st to 10th	Night	65% 3 11% 14% 7%	6787
	11th to 20th	Night	68% 4 6% 18% 4	6772
	21st to end	Night	66% 3 12% 15% 4	6974
February	1st to 10th	Night	58% 4 13% 16% 9%	2653
	11th to 20th	Night	46% 5% 17% 22% 10% 1	2534
	21st to end	Night	55% 4 12% 19% 10%	2085
March	1st to 10th	Night	50% 4 16% 18% 10% 3	5236
	11th to 20th	Night	48% 4 14% 23% 12%	4980
	21st to end	Night	53% 3 9% 23% 11%	5467
April	1st to 10th	Night	44% 3 10% 25% 14% 3	1975
	11th to 20th	Night	50% 3 8% 22% 15% 2	1779
	21st to end	Night	47% 3 11% 27% 10% 2	1800
May	1st to 10th	Night	40% 2 10% 28% 20%	3903
	11th to 20th	Night	47% 2 10% 25% 15% 2	3381
	21st to end	Night	35% 3 8% 25% 23% 5%	3470
June	1st to 10th	Night	36% 6% 17% 26% 14% 2	1400
	11th to 20th	Night	36% 5% 17% 28% 12% 2	1400
	21st to end	Night	37% 6% 20% 28% 8% 1	1400
July	1st to 10th	Night	30% 5% 26% 30% 8% 1	3145
	11th to 20th	Night	28% 4 19% 40% 8%	3138
	21st to end	Night	31% 4 25% 32% 7% 1	3472
August	1st to 10th	Night	31% 3 17% 35% 13% 1	2808
	11th to 20th	Night	32% 3 25% 31% 9%	2915
	21st to end	Night	35% 2 19% 34% 9% 1	3234
September	1st to 10th	Night	30% 5% 15% 36% 14% 1	1922
	11th to 20th	Night	37% 5% 20% 27% 10% 1	2200
	21st to end	Night	40% 4 14% 30% 12% 1	2200
October	1st to 10th	Night	39% 3 11% 33% 13% 1	3758
	11th to 20th	Night	42% 3 12% 32% 11%	3804
	21st to end	Night	47% 3 13% 30% 7%	4467
November	1st to 10th	Night	56% 4 15% 18% 6% 1	2698
	11th to 20th	Night	60% 5% 14% 16% 5% 1	2800
	21st to end	Night	63% 5% 14% 14% 5%	2880
December	1st to 10th	Night	74% 4 11% 8% 3	4900
	11th to 20th	Night	60% 4 13% 12% 11%	5566
	21st to end	Night	68% 3 8% 16% 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	13% 8% 31% 31% 15% 2	300
	11th to 20th	Day	11% 9% 33% 35% 12%	300
	21st to end	Day	16% 8% 35% 28% 11% 2	330
February	1st to 10th	Day	13% 13% 33% 32% 8% 1	300
	11th to 20th	Day	8% 11% 40% 29% 11% 1	300
	21st to end	Day	9% 9% 44% 27% 9% 1	249
March	1st to 10th	Day	13% 8% 35% 32% 11% 2	300
	11th to 20th	Day	15% 11% 35% 27% 11% 1	300
	21st to end	Day	18% 9% 30% 28% 12% 2	330
April	1st to 10th	Day	14% 14% 34% 27% 8% 3	520
	11th to 20th	Day	20% 13% 33% 23% 10% 1	690
	21st to end	Day	21% 10% 30% 25% 12% 2	700
May	1st to 10th	Day	15% 12% 32% 28% 11% 2	703
	11th to 20th	Day	20% 8% 31% 25% 13% 3	725
	21st to end	Day	19% 8% 26% 27% 16% 4	789
June	1st to 10th	Day	13% 11% 26% 29% 15% 6%	730
	11th to 20th	Day	15% 10% 31% 29% 12% 3	730
	21st to end	Day	13% 9% 29% 27% 16% 6%	730
July	1st to 10th	Day	10% 4 27% 30% 20% 10%	721
	11th to 20th	Day	12% 7% 28% 28% 18% 7%	718
	21st to end	Day	7% 5% 26% 35% 20% 9%	794
August	1st to 10th	Day	8% 4 25% 33% 23% 7%	726
	11th to 20th	Day	10% 5% 23% 34% 19% 9%	715
	21st to end	Day	12% 8% 27% 29% 19% 4	803
September	1st to 10th	Day	10% 7% 34% 31% 15% 4	603
	11th to 20th	Day	17% 8% 34% 28% 11% 2	330
	21st to end	Day	18% 9% 37% 23% 12% 1	330
October	1st to 10th	Day	20% 12% 27% 28% 9% 4	309
	11th to 20th	Day	17% 9% 37% 26% 11% 1	300
	21st to end	Day	28% 8% 32% 23% 8% 1	330
November	1st to 10th	Day	24% 7% 30% 26% 11% 2	300
	11th to 20th	Day	21% 10% 39% 22% 7% 1	300
	21st to end	Day	19% 12% 37% 26% 5%	300
December	1st to 10th	Day	14% 8% 35% 30% 10% 2	300
	11th to 20th	Day	16% 11% 39% 28% 6%	300
	21st to end	Day	13% 8% 36% 26% 12% 5%	330
January	1st to 10th	Night	11% 7% 36% 31% 14% 2	1000
	11th to 20th	Night	14% 7% 33% 35% 11%	1000
	21st to end	Night	14% 8% 35% 32% 10% 1	1100
February	1st to 10th	Night	14% 7% 29% 37% 14% 1	1000
	11th to 20th	Night	12% 6% 32% 34% 13% 3	979
	21st to end	Night	10% 7% 37% 32% 12% 2	765
March	1st to 10th	Night	15% 7% 34% 30% 13% 2	740
	11th to 20th	Night	10% 7% 41% 31% 10% 1	600
	21st to end	Night	18% 8% 28% 28% 13% 3	660
April	1st to 10th	Night	14% 8% 34% 33% 10% 1	600
	11th to 20th	Night	19% 6% 31% 34% 10% 1	593
	21st to end	Night	16% 7% 31% 34% 12% 1	600
May	1st to 10th	Night	17% 7% 34% 31% 10%	600
	11th to 20th	Night	18% 9% 29% 31% 12% 1	591
	21st to end	Night	18% 7% 31% 31% 12%	650
June	1st to 10th	Night	15% 5% 29% 35% 15% 1	600
	11th to 20th	Night	13% 5% 31% 35% 15% 1	600
	21st to end	Night	10% 5% 26% 40% 18% 2	600
July	1st to 10th	Night	7% 2 23% 44% 22% 1	585
	11th to 20th	Night	6% 4 26% 44% 19% 1	582
	21st to end	Night	7% 3 21% 46% 20% 3	657
August	1st to 10th	Night	8% 4 22% 46% 19% 2	597
	11th to 20th	Night	11% 3 22% 39% 22% 3	594
	21st to end	Night	11% 6% 25% 38% 20%	660
September	1st to 10th	Night	11% 4 29% 38% 17% 2	600
	11th to 20th	Night	16% 5% 29% 38% 13% 1	600
	21st to end	Night	18% 7% 31% 35% 10% 1	600
October	1st to 10th	Night	22% 6% 33% 30% 8%	720
	11th to 20th	Night	21% 9% 32% 29% 9%	773
	21st to end	Night	20% 9% 32% 31% 8% 1	1045
November	1st to 10th	Night	20% 8% 36% 27% 9%	975
	11th to 20th	Night	19% 8% 34% 29% 9% 2	1000
	21st to end	Night	18% 11% 39% 25% 6% 1	1000
December	1st to 10th	Night	14% 7% 33% 33% 12% 1	1000
	11th to 20th	Night	18% 8% 35% 32% 6% 1	1000
	21st to end	Night	19% 7% 32% 29% 11% 1	1100

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