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 2024-01-12.

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% 9% 4 7% 6% 4 5% 5% 6% 7% 34%	74650
	Night	11% 9% 4 8% 7% 4 5% 5% 6% 7% 34%	75090
Transparency	Day	48% 5% 15% 23% 8% 1	74334
	Night	49% 4 14% 22% 9% 1	74925
Seeing	Day	15% 8% 31% 28% 14% 4	15020
	Night	15% 7% 31% 34% 13% 1	25087

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	7% 14% 6% 10% 9% 4 8% 8% 6% 7% 22%	1329
	11th to 20th	Day	8% 13% 7% 12% 10% 7% 8% 10% 7% 5% 15%	1279
	21st to end	Day	11% 14% 8% 13% 11% 4 10% 6% 7% 6% 11%	1584
February	1st to 10th	Day	7% 12% 7% 12% 8% 5% 7% 9% 7% 7% 20%	1570
	11th to 20th	Day	8% 8% 4 8% 9% 7% 8% 9% 7% 8% 24%	1574
	21st to end	Day	7% 8% 5% 12% 10% 7% 8% 6% 6% 7% 24%	1402
March	1st to 10th	Day	13% 12% 6% 9% 9% 4 5% 6% 5% 7% 24%	1854
	11th to 20th	Day	8% 11% 5% 10% 9% 4 6% 5% 6% 6% 31%	1978
	21st to end	Day	13% 12% 4 10% 7% 4 5% 4 6% 7% 28%	2178
April	1st to 10th	Day	10% 12% 5% 8% 7% 3 5% 5% 6% 6% 34%	2176
	11th to 20th	Day	14% 9% 4 7% 7% 3 5% 4 7% 6% 33%	2312
	21st to end	Day	18% 9% 4 7% 6% 3 4 4 5% 7% 33%	2340
May	1st to 10th	Day	16% 9% 3 6% 5% 3 5% 4 4 6% 38%	2403
	11th to 20th	Day	18% 7% 3 5% 4 3 4 5% 6% 7% 39%	2564
	21st to end	Day	19% 6% 3 5% 4 3 4 5% 6% 7% 38%	2918
June	1st to 10th	Day	13% 6% 3 6% 6% 3 5% 5% 7% 9% 38%	2700
	11th to 20th	Day	15% 6% 2 5% 6% 4 5% 5% 7% 8% 37%	2700
	21st to end	Day	13% 5% 3 5% 5% 4 6% 6% 7% 9% 36%	2700
July	1st to 10th	Day	8% 3 2 4 5% 3 4 7% 7% 9% 49%	2700
	11th to 20th	Day	11% 5% 2 5% 5% 3 6% 5% 5% 8% 45%	2700
	21st to end	Day	7% 4 2 4 4 3 4 5% 6% 8% 54%	2898
August	1st to 10th	Day	9% 5% 2 4 5% 3 6% 5% 6% 9% 47%	2396
	11th to 20th	Day	11% 4 2 4 4 3 5% 5% 6% 9% 47%	2301
	21st to end	Day	12% 4 2 5% 5% 3 3 5% 5% 7% 48%	2574
September	1st to 10th	Day	11% 5% 2 4 5% 3 4 5% 6% 7% 49%	2227
	11th to 20th	Day	14% 6% 2 5% 4 3 4 5% 7% 9% 41%	1980
	21st to end	Day	16% 6% 3 5% 5% 2 4 4 6% 8% 40%	1980
October	1st to 10th	Day	18% 9% 3 6% 6% 3 4 4 5% 6% 35%	1830
	11th to 20th	Day	14% 11% 4 7% 6% 3 4 4 5% 7% 35%	1787
	21st to end	Day	16% 13% 4 8% 7% 4 5% 4 4 7% 28%	1782
November	1st to 10th	Day	14% 15% 5% 9% 6% 3 4 4 4 6% 29%	1519
	11th to 20th	Day	11% 15% 7% 11% 9% 3 4 5% 4 6% 25%	1520
	21st to end	Day	13% 13% 6% 9% 10% 5% 7% 5% 5% 4 24%	1444
December	1st to 10th	Day	7% 15% 6% 13% 9% 5% 7% 7% 6% 5% 20%	1330
	11th to 20th	Day	9% 15% 7% 13% 8% 5% 6% 5% 7% 7% 17%	1679
	21st to end	Day	9% 14% 5% 11% 10% 5% 9% 7% 7% 7% 15%	2442
January	1st to 10th	Night	6% 13% 7% 10% 9% 5% 7% 8% 7% 6% 23%	2837
	11th to 20th	Night	9% 14% 7% 12% 9% 5% 8% 6% 5% 5% 20%	2708
	21st to end	Night	8% 14% 6% 13% 9% 5% 8% 7% 7% 6% 16%	2772
February	1st to 10th	Night	8% 10% 5% 10% 9% 5% 8% 8% 6% 6% 25%	2388
	11th to 20th	Night	8% 8% 4 7% 8% 4 7% 7% 8% 8% 31%	2273
	21st to end	Night	7% 10% 5% 13% 9% 5% 6% 5% 5% 6% 31%	1870
March	1st to 10th	Night	11% 12% 5% 9% 7% 4 5% 5% 5% 7% 30%	2106
	11th to 20th	Night	7% 9% 5% 8% 6% 3 5% 4 5% 6% 41%	1980
	21st to end	Night	13% 10% 3 7% 6% 3 5% 5% 6% 8% 34%	2178
April	1st to 10th	Night	10% 8% 3 5% 6% 4 5% 6% 5% 7% 39%	1779
	11th to 20th	Night	13% 11% 4 6% 6% 3 5% 5% 5% 5% 37%	1599
	21st to end	Night	13% 9% 3 5% 6% 3 6% 5% 5% 7% 37%	1620
May	1st to 10th	Night	15% 7% 3 6% 6% 3 4 4 4 8% 41%	1555
	11th to 20th	Night	15% 7% 3 7% 4 4 4 3 6% 7% 42%	1331
	21st to end	Night	15% 8% 2 5% 4 2 3 4 6% 9% 41%	1358
June	1st to 10th	Night	13% 4 2 4 5% 3 5% 5% 5% 9% 44%	1260
	11th to 20th	Night	12% 4 2 5% 5% 3 4 5% 6% 9% 45%	1260
	21st to end	Night	9% 3 2 5% 7% 5% 5% 5% 7% 10% 43%	1260
July	1st to 10th	Night	7% 3 1 3 4 3 4 5% 6% 8% 57%	1260
	11th to 20th	Night	5% 3 1 4 3 4 5% 6% 8% 7% 53%	1260
	21st to end	Night	7% 3 2 3 2 2 4 3 6% 9% 58%	1418
August	1st to 10th	Night	6% 3 2 5% 4 2 4 4 6% 9% 54%	1543
	11th to 20th	Night	10% 4 1 3 3 2 4 6% 5% 10% 51%	1600
	21st to end	Night	10% 4 2 4 4 2 4 4 5% 7% 54%	1782
September	1st to 10th	Night	9% 4 2 4 4 2 4 5% 5% 7% 53%	1728
	11th to 20th	Night	12% 6% 2 4 4 3 4 6% 6% 7% 48%	1980
	21st to end	Night	16% 6% 2 5% 4 3 4 5% 6% 7% 43%	1980
October	1st to 10th	Night	16% 9% 3 6% 5% 3 5% 5% 4 7% 36%	2111
	11th to 20th	Night	17% 9% 3 6% 5% 3 4 5% 5% 6% 37%	2172
	21st to end	Night	15% 11% 4 8% 7% 3 4 5% 5% 6% 32%	2574
November	1st to 10th	Night	14% 12% 6% 9% 6% 3 4 5% 5% 6% 29%	2559
	11th to 20th	Night	11% 14% 7% 10% 8% 4 4 5% 5% 6% 27%	2660
	21st to end	Night	12% 12% 6% 11% 8% 5% 5% 4 4 5% 27%	2736
December	1st to 10th	Night	7% 12% 6% 12% 11% 5% 7% 6% 6% 6% 21%	2850
	11th to 20th	Night	10% 15% 6% 12% 11% 4 5% 5% 5% 7% 21%	3518
	21st to end	Night	11% 12% 5% 11% 11% 6% 6% 5% 6% 6% 22%	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	59% 4 14% 17% 6%	1329
	11th to 20th	Day	66% 5% 10% 15% 4	1279
	21st to end	Day	73% 3 5% 11% 7%	1584
February	1st to 10th	Day	60% 4 13% 14% 8% 1	1570
	11th to 20th	Day	53% 6% 13% 19% 9%	1583
	21st to end	Day	58% 5% 12% 17% 8%	1402
March	1st to 10th	Day	60% 5% 14% 15% 6%	1854
	11th to 20th	Day	53% 5% 14% 20% 7%	1980
	21st to end	Day	55% 5% 14% 19% 7%	2178
April	1st to 10th	Day	50% 4 10% 24% 11% 1	2176
	11th to 20th	Day	50% 4 11% 22% 11% 1	2312
	21st to end	Day	51% 4 16% 21% 7% 2	2340
May	1st to 10th	Day	48% 3 11% 24% 13% 1	2403
	11th to 20th	Day	44% 4 12% 27% 12% 1	2568
	21st to end	Day	46% 4 13% 25% 11% 1	2918
June	1st to 10th	Day	42% 4 18% 26% 9%	2700
	11th to 20th	Day	44% 5% 16% 24% 10% 1	2700
	21st to end	Day	43% 7% 19% 25% 6% 1	2700
July	1st to 10th	Day	29% 6% 19% 34% 11% 1	2626
	11th to 20th	Day	37% 5% 18% 29% 11%	2619
	21st to end	Day	29% 5% 19% 34% 12% 1	2737
August	1st to 10th	Day	33% 6% 19% 33% 9% 1	2380
	11th to 20th	Day	34% 5% 21% 33% 7%	2301
	21st to end	Day	35% 5% 16% 33% 11%	2574
September	1st to 10th	Day	34% 4 17% 32% 11% 1	2227
	11th to 20th	Day	40% 5% 21% 27% 6% 1	1980
	21st to end	Day	42% 5% 16% 32% 5%	1980
October	1st to 10th	Day	51% 4 16% 21% 8%	1830
	11th to 20th	Day	50% 3 14% 24% 7% 1	1787
	21st to end	Day	58% 5% 16% 18% 4	1782
November	1st to 10th	Day	57% 4 15% 18% 5% 1	1519
	11th to 20th	Day	62% 5% 15% 14% 5%	1520
	21st to end	Day	64% 5% 14% 14% 3	1444
December	1st to 10th	Day	64% 5% 15% 11% 4	1330
	11th to 20th	Day	65% 4 14% 13% 5%	1680
	21st to end	Day	67% 4 7% 16% 5%	2442
January	1st to 10th	Night	59% 5% 13% 18% 6%	2837
	11th to 20th	Night	64% 5% 9% 17% 5%	2708
	21st to end	Night	65% 5% 10% 14% 6%	2772
February	1st to 10th	Night	57% 4 14% 16% 9%	2388
	11th to 20th	Night	47% 5% 18% 19% 10% 1	2274
	21st to end	Night	54% 4 12% 20% 10%	1870
March	1st to 10th	Night	54% 4 13% 21% 8%	2106
	11th to 20th	Night	44% 4 13% 27% 12% 1	1980
	21st to end	Night	48% 6% 14% 20% 12% 1	2178
April	1st to 10th	Night	44% 4 11% 23% 15% 3	1779
	11th to 20th	Night	49% 3 8% 22% 16% 2	1599
	21st to end	Night	46% 3 11% 27% 10% 2	1620
May	1st to 10th	Night	44% 3 12% 25% 16% 1	1555
	11th to 20th	Night	42% 3 11% 27% 14% 2	1331
	21st to end	Night	40% 5% 14% 22% 17% 1	1358
June	1st to 10th	Night	37% 6% 17% 26% 13% 1	1260
	11th to 20th	Night	36% 5% 16% 28% 13% 2	1260
	21st to end	Night	36% 6% 21% 28% 8% 1	1260
July	1st to 10th	Night	24% 5% 19% 37% 13% 2	1225
	11th to 20th	Night	27% 6% 19% 30% 17% 1	1218
	21st to end	Night	24% 4 15% 40% 16% 2	1339
August	1st to 10th	Night	27% 4 18% 38% 11% 1	1535
	11th to 20th	Night	28% 4 23% 33% 12% 1	1600
	21st to end	Night	30% 3 15% 36% 15% 1	1782
September	1st to 10th	Night	30% 5% 14% 35% 16% 1	1728
	11th to 20th	Night	35% 5% 19% 28% 11% 1	1980
	21st to end	Night	41% 4 14% 30% 10%	1980
October	1st to 10th	Night	49% 4 15% 23% 8% 1	2111
	11th to 20th	Night	48% 4 13% 27% 7%	2172
	21st to end	Night	54% 4 14% 23% 5%	2574
November	1st to 10th	Night	56% 4 15% 18% 6% 1	2559
	11th to 20th	Night	60% 5% 14% 16% 5% 1	2660
	21st to end	Night	61% 5% 14% 14% 6%	2736
December	1st to 10th	Night	63% 5% 16% 13% 4	2850
	11th to 20th	Night	63% 4 14% 12% 6%	3516
	21st to end	Night	62% 4 11% 18% 6%	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	12% 8% 32% 31% 14% 2	270
	11th to 20th	Day	12% 10% 30% 36% 12%	243
	21st to end	Day	17% 6% 33% 30% 12% 2	264
February	1st to 10th	Day	12% 11% 38% 30% 8% 1	240
	11th to 20th	Day	10% 11% 40% 26% 11% 1	240
	21st to end	Day	9% 6% 45% 29% 11%	198
March	1st to 10th	Day	13% 7% 33% 35% 10% 2	240
	11th to 20th	Day	15% 10% 32% 30% 12% 2	240
	21st to end	Day	18% 7% 31% 27% 14% 3	264
April	1st to 10th	Day	15% 13% 36% 26% 8% 2	436
	11th to 20th	Day	19% 12% 33% 24% 12% 1	590
	21st to end	Day	20% 10% 31% 24% 12% 2	600
May	1st to 10th	Day	15% 12% 31% 28% 11% 2	603
	11th to 20th	Day	20% 8% 28% 25% 15% 3	625
	21st to end	Day	19% 8% 27% 27% 16% 3	679
June	1st to 10th	Day	12% 10% 26% 29% 16% 7%	630
	11th to 20th	Day	16% 11% 31% 27% 12% 3	630
	21st to end	Day	13% 7% 27% 29% 17% 7%	630
July	1st to 10th	Day	10% 4 28% 30% 20% 8%	621
	11th to 20th	Day	12% 7% 28% 29% 18% 6%	618
	21st to end	Day	7% 5% 24% 35% 21% 9%	684
August	1st to 10th	Day	7% 4 25% 33% 24% 7%	626
	11th to 20th	Day	10% 6% 22% 34% 19% 10%	615
	21st to end	Day	13% 8% 26% 29% 20% 5%	693
September	1st to 10th	Day	10% 7% 35% 30% 15% 3	517
	11th to 20th	Day	14% 7% 37% 26% 13% 2	270
	21st to end	Day	20% 8% 36% 26% 9% 1	270
October	1st to 10th	Day	21% 11% 26% 27% 10% 4	270
	11th to 20th	Day	17% 7% 36% 27% 12% 1	270
	21st to end	Day	29% 7% 33% 21% 8% 1	297
November	1st to 10th	Day	24% 7% 31% 26% 10% 2	270
	11th to 20th	Day	19% 10% 40% 23% 7% 1	270
	21st to end	Day	20% 13% 38% 24% 5%	270
December	1st to 10th	Day	13% 8% 36% 31% 11% 1	270
	11th to 20th	Day	16% 11% 39% 28% 6%	270
	21st to end	Day	13% 8% 36% 27% 13% 4	297
January	1st to 10th	Night	11% 7% 35% 31% 14% 1	950
	11th to 20th	Night	15% 6% 32% 35% 11%	908
	21st to end	Night	15% 7% 35% 33% 10% 1	990
February	1st to 10th	Night	13% 6% 28% 38% 14% 1	900
	11th to 20th	Night	13% 6% 32% 34% 12% 3	879
	21st to end	Night	10% 7% 36% 33% 12% 2	686
March	1st to 10th	Night	15% 6% 32% 30% 14% 2	666
	11th to 20th	Night	11% 6% 40% 31% 11% 1	540
	21st to end	Night	18% 8% 27% 29% 14% 3	594
April	1st to 10th	Night	14% 8% 34% 32% 11% 1	540
	11th to 20th	Night	18% 6% 30% 35% 11% 1	533
	21st to end	Night	16% 6% 31% 34% 12% 1	540
May	1st to 10th	Night	18% 8% 32% 31% 11%	540
	11th to 20th	Night	18% 8% 29% 32% 13% 1	531
	21st to end	Night	19% 7% 32% 31% 11%	584
June	1st to 10th	Night	15% 5% 27% 36% 16% 1	540
	11th to 20th	Night	13% 5% 30% 35% 16% 1	540
	21st to end	Night	10% 4 22% 41% 20% 2	540
July	1st to 10th	Night	7% 2 24% 45% 21% 1	525
	11th to 20th	Night	6% 5% 26% 44% 18% 1	522
	21st to end	Night	7% 3 20% 46% 20% 3	591
August	1st to 10th	Night	8% 4 22% 46% 18% 2	537
	11th to 20th	Night	10% 4 23% 39% 22% 3	534
	21st to end	Night	11% 6% 24% 38% 21%	594
September	1st to 10th	Night	11% 4 29% 36% 17% 2	540
	11th to 20th	Night	15% 4 29% 38% 14% 1	540
	21st to end	Night	18% 6% 31% 35% 9%	540
October	1st to 10th	Night	23% 6% 32% 30% 9%	671
	11th to 20th	Night	22% 8% 31% 29% 9%	732
	21st to end	Night	21% 9% 31% 30% 8% 1	990
November	1st to 10th	Night	20% 8% 36% 27% 9%	925
	11th to 20th	Night	18% 8% 35% 29% 9% 2	950
	21st to end	Night	18% 11% 39% 25% 6% 1	950
December	1st to 10th	Night	13% 7% 33% 33% 12% 1	950
	11th to 20th	Night	18% 8% 33% 33% 7% 1	950
	21st to end	Night	19% 7% 33% 29% 11% 1	1045

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