Smiley's Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Smiley's Provincial Park clear sky chart from 2005-11-06 to 2025-05-11.

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	19% 13% 4 9% 5% 4 4 3 5% 6% 26%	114644
	Night	18% 13% 5% 11% 6% 4 4 3 4 5% 26%	114415
Transparency	Day	58% 5% 11% 17% 8% 1	118268
	Night	59% 5% 11% 17% 8% 1	118955
Seeing	Day	30% 19% 30% 15% 5% 1	18012
	Night	27% 17% 30% 20% 5%	25486

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	14% 25% 8% 15% 8% 4 3 2 2 2 16%	3616
	11th to 20th	Day	14% 20% 9% 20% 6% 5% 4 3 4 4 11%	3703
	21st to end	Day	14% 13% 7% 12% 8% 8% 5% 3 4 4 22%	4466
February	1st to 10th	Day	18% 17% 5% 11% 9% 7% 4 4 4 4 17%	1800
	11th to 20th	Day	16% 17% 6% 15% 7% 5% 3 3 4 5% 19%	1753
	21st to end	Day	11% 16% 5% 9% 9% 5% 3 3 5% 5% 28%	1510
March	1st to 10th	Day	23% 16% 5% 12% 5% 5% 3 2 3 4 21%	4919
	11th to 20th	Day	13% 19% 6% 10% 4 4 3 3 5% 6% 26%	4980
	21st to end	Day	24% 20% 5% 10% 5% 4 3 3 3 4 20%	5466
April	1st to 10th	Day	24% 17% 5% 8% 6% 3 3 3 4 4 24%	2393
	11th to 20th	Day	20% 14% 3 7% 5% 4 3 4 5% 6% 30%	2447
	21st to end	Day	22% 14% 3 7% 4 4 4 4 5% 6% 28%	2600
May	1st to 10th	Day	26% 18% 3 8% 4 4 3 3 5% 6% 21%	4354
	11th to 20th	Day	21% 12% 3 8% 5% 4 4 3 5% 6% 30%	4398
	21st to end	Day	17% 10% 3 7% 5% 4 5% 4 7% 9% 29%	4836
June	1st to 10th	Day	26% 11% 3 7% 5% 4 4 4 6% 6% 24%	2660
	11th to 20th	Day	21% 10% 3 6% 5% 4 3 3 5% 7% 32%	2778
	21st to end	Day	25% 10% 4 8% 4 4 4 3 5% 7% 26%	2850
July	1st to 10th	Day	22% 8% 2 6% 4 5% 5% 4 6% 8% 30%	4669
	11th to 20th	Day	17% 8% 3 8% 5% 5% 6% 4 6% 8% 31%	4440
	21st to end	Day	15% 9% 3 8% 5% 5% 5% 5% 7% 8% 31%	4692
August	1st to 10th	Day	23% 10% 3 8% 5% 5% 5% 4 5% 7% 26%	4105
	11th to 20th	Day	15% 8% 3 8% 5% 6% 5% 4 7% 7% 32%	4045
	21st to end	Day	12% 5% 3 5% 4 4 5% 4 7% 8% 43%	4351
September	1st to 10th	Day	18% 6% 2 6% 5% 3 4 3 5% 7% 41%	2280
	11th to 20th	Day	19% 7% 3 6% 3 3 4 3 5% 6% 42%	2210
	21st to end	Day	19% 8% 2 5% 4 4 3 3 4 7% 41%	2028
October	1st to 10th	Day	18% 8% 2 6% 4 5% 4 3 5% 7% 37%	1900
	11th to 20th	Day	20% 10% 3 7% 4 4 5% 3 6% 7% 32%	1900
	21st to end	Day	20% 15% 4 8% 5% 3 4 4 4 4 30%	2090
November	1st to 10th	Day	22% 14% 3 7% 6% 5% 5% 4 4 5% 26%	1617
	11th to 20th	Day	20% 21% 6% 7% 4 3 4 3 5% 5% 23%	1600
	21st to end	Day	19% 19% 5% 9% 7% 5% 4 3 4 4 20%	1600
December	1st to 10th	Day	18% 17% 10% 18% 5% 3 3 2 3 4 14%	2610
	11th to 20th	Day	24% 16% 5% 14% 7% 4 4 3 3 2 17%	2996
	21st to end	Day	19% 14% 9% 16% 7% 4 4 3 3 5% 17%	3982
January	1st to 10th	Night	14% 20% 8% 18% 7% 4 3 2 3 4 16%	6349
	11th to 20th	Night	14% 19% 8% 21% 6% 5% 4 3 3 3 14%	6194
	21st to end	Night	12% 12% 6% 18% 11% 7% 5% 3 4 5% 18%	6490
February	1st to 10th	Night	19% 15% 5% 14% 10% 5% 5% 3 4 4 16%	2600
	11th to 20th	Night	17% 15% 5% 12% 9% 6% 3 4 4 5% 19%	2533
	21st to end	Night	12% 16% 5% 12% 8% 5% 4 3 4 5% 26%	2119
March	1st to 10th	Night	23% 16% 5% 13% 8% 5% 3 3 3 3 20%	4920
	11th to 20th	Night	16% 17% 6% 8% 4 4 4 4 4 5% 27%	4979
	21st to end	Night	25% 18% 6% 10% 4 3 3 2 3 3 23%	5466
April	1st to 10th	Night	23% 15% 4 8% 5% 4 4 3 4 5% 26%	2006
	11th to 20th	Night	22% 13% 3 7% 6% 4 3 3 4 5% 31%	1899
	21st to end	Night	22% 13% 3 7% 5% 4 4 3 4 5% 29%	1800
May	1st to 10th	Night	24% 19% 3 6% 4 4 4 4 5% 5% 23%	2808
	11th to 20th	Night	21% 11% 2 6% 4 4 4 4 7% 7% 30%	2513
	21st to end	Night	17% 9% 4 9% 6% 5% 6% 3 5% 7% 29%	2749
June	1st to 10th	Night	25% 9% 3 6% 4 4 5% 3 6% 8% 27%	1520
	11th to 20th	Night	19% 9% 3 6% 5% 4 4 4 5% 7% 35%	1415
	21st to end	Night	22% 10% 3 8% 6% 4 5% 4 5% 7% 25%	1330
July	1st to 10th	Night	20% 10% 3 8% 6% 4 5% 4 7% 7% 26%	2264
	11th to 20th	Night	19% 8% 2 7% 3 4 5% 4 7% 9% 32%	2530
	21st to end	Night	14% 7% 3 7% 4 4 4 4 5% 8% 40%	2866
August	1st to 10th	Night	20% 8% 3 7% 4 4 5% 4 6% 7% 33%	2825
	11th to 20th	Night	15% 8% 3 8% 5% 5% 5% 4 5% 9% 34%	2782
	21st to end	Night	13% 5% 2 5% 3 3 4 3 5% 7% 50%	3304
September	1st to 10th	Night	14% 7% 3 5% 5% 4 4 3 4 7% 44%	1900
	11th to 20th	Night	17% 7% 3 5% 3 2 4 3 4 7% 43%	1966
	21st to end	Night	17% 9% 3 7% 4 4 4 3 5% 6% 39%	2152
October	1st to 10th	Night	19% 6% 3 6% 5% 4 4 4 5% 6% 39%	2280
	11th to 20th	Night	19% 9% 3 6% 4 4 4 2 5% 7% 36%	2280
	21st to end	Night	24% 11% 3 7% 4 4 4 3 4 6% 30%	2508
November	1st to 10th	Night	21% 14% 3 7% 5% 3 4 3 5% 5% 31%	2679
	11th to 20th	Night	19% 18% 5% 10% 6% 4 4 3 4 4 22%	2800
	21st to end	Night	21% 16% 6% 10% 6% 4 3 3 4 5% 22%	2800
December	1st to 10th	Night	16% 15% 9% 18% 6% 4 4 3 4 4 18%	4580
	11th to 20th	Night	21% 16% 4 14% 6% 4 3 2 3 3 23%	5213
	21st to end	Night	21% 16% 7% 12% 6% 3 3 2 3 3 24%	6996

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	75% 4 11% 7% 3	3617
	11th to 20th	Day	75% 6% 8% 9% 2	3732
	21st to end	Day	62% 4 9% 11% 12% 2	4466
February	1st to 10th	Day	69% 5% 9% 9% 6% 1	1800
	11th to 20th	Day	67% 6% 9% 12% 6%	1761
	21st to end	Day	57% 5% 11% 16% 9% 2	1510
March	1st to 10th	Day	68% 3 7% 12% 8% 2	4923
	11th to 20th	Day	58% 5% 14% 17% 6%	4980
	21st to end	Day	71% 3 4 14% 8% 1	5466
April	1st to 10th	Day	64% 4 6% 12% 10% 3	2393
	11th to 20th	Day	54% 6% 9% 19% 11% 1	2447
	21st to end	Day	57% 5% 9% 17% 10% 2	2600
May	1st to 10th	Day	63% 6% 9% 14% 6% 1	4368
	11th to 20th	Day	53% 9% 13% 19% 7%	4402
	21st to end	Day	48% 10% 17% 17% 9% 1	4836
June	1st to 10th	Day	59% 7% 11% 17% 5%	2660
	11th to 20th	Day	52% 6% 12% 19% 10% 1	2778
	21st to end	Day	58% 7% 10% 15% 9%	2850
July	1st to 10th	Day	53% 5% 12% 17% 12% 1	4596
	11th to 20th	Day	51% 6% 15% 21% 7%	4364
	21st to end	Day	48% 6% 17% 21% 7%	4542
August	1st to 10th	Day	59% 5% 12% 17% 7%	4092
	11th to 20th	Day	50% 5% 13% 24% 8%	4084
	21st to end	Day	38% 4 13% 29% 16% 1	4351
September	1st to 10th	Day	43% 5% 13% 24% 13% 2	2280
	11th to 20th	Day	43% 5% 12% 24% 14% 1	2210
	21st to end	Day	44% 5% 10% 25% 15%	2028
October	1st to 10th	Day	51% 3 10% 25% 11%	3160
	11th to 20th	Day	47% 5% 8% 26% 14%	3140
	21st to end	Day	49% 4 14% 21% 11%	3428
November	1st to 10th	Day	60% 6% 8% 18% 7%	1617
	11th to 20th	Day	63% 6% 12% 13% 5% 1	1600
	21st to end	Day	65% 8% 12% 11% 4	1600
December	1st to 10th	Day	74% 3 6% 14% 2	2610
	11th to 20th	Day	73% 4 6% 11% 5%	2995
	21st to end	Day	70% 4 9% 12% 5%	3982
January	1st to 10th	Night	70% 6% 9% 13% 2	6349
	11th to 20th	Night	74% 5% 8% 10% 3	6240
	21st to end	Night	66% 5% 8% 13% 6%	6490
February	1st to 10th	Night	70% 5% 8% 9% 6% 1	2600
	11th to 20th	Night	67% 5% 12% 10% 5% 1	2536
	21st to end	Night	59% 5% 11% 17% 8% 1	2119
March	1st to 10th	Night	70% 3 5% 11% 9% 1	4929
	11th to 20th	Night	58% 4 12% 17% 7% 1	4980
	21st to end	Night	68% 3 5% 16% 8% 1	5466
April	1st to 10th	Night	60% 6% 8% 13% 10% 3	2006
	11th to 20th	Night	56% 4 8% 18% 13% 1	1899
	21st to end	Night	57% 5% 10% 16% 11% 2	1800
May	1st to 10th	Night	62% 6% 12% 13% 6% 1	2814
	11th to 20th	Night	50% 9% 13% 20% 7% 1	2514
	21st to end	Night	52% 9% 17% 17% 5% 1	2750
June	1st to 10th	Night	55% 8% 13% 18% 6%	1520
	11th to 20th	Night	49% 5% 14% 20% 11% 1	1415
	21st to end	Night	57% 8% 14% 14% 7% 1	1330
July	1st to 10th	Night	56% 7% 13% 15% 8% 1	2228
	11th to 20th	Night	48% 6% 19% 17% 9%	2482
	21st to end	Night	43% 6% 15% 22% 12% 1	2776
August	1st to 10th	Night	51% 7% 15% 23% 5%	2813
	11th to 20th	Night	48% 7% 14% 24% 7%	2809
	21st to end	Night	34% 4 18% 27% 15% 1	3303
September	1st to 10th	Night	39% 7% 13% 26% 14% 2	1900
	11th to 20th	Night	40% 6% 11% 29% 13% 1	1966
	21st to end	Night	45% 6% 11% 26% 13% 1	2152
October	1st to 10th	Night	51% 3 10% 25% 10%	3800
	11th to 20th	Night	45% 3 11% 24% 16%	3779
	21st to end	Night	47% 4 13% 22% 15%	4120
November	1st to 10th	Night	54% 6% 13% 17% 9% 1	2679
	11th to 20th	Night	63% 6% 11% 14% 6%	2800
	21st to end	Night	64% 5% 15% 12% 3	2800
December	1st to 10th	Night	69% 4 9% 16% 2	4580
	11th to 20th	Night	67% 3 7% 16% 6% 1	5215
	21st to end	Night	65% 4 9% 16% 5%	6996

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	35% 23% 29% 12% 1	400
	11th to 20th	Day	37% 19% 29% 11% 4	400
	21st to end	Day	27% 26% 33% 12% 2	440
February	1st to 10th	Day	34% 25% 27% 12% 2	400
	11th to 20th	Day	39% 27% 24% 9% 2	396
	21st to end	Day	29% 23% 33% 12% 2 1	331
March	1st to 10th	Day	35% 25% 31% 7% 2	496
	11th to 20th	Day	29% 31% 26% 9% 4	500
	21st to end	Day	37% 29% 23% 8% 3	550
April	1st to 10th	Day	45% 23% 24% 7% 1	500
	11th to 20th	Day	36% 27% 25% 10% 2	492
	21st to end	Day	34% 25% 25% 12% 4	500
May	1st to 10th	Day	41% 20% 25% 10% 3 1	569
	11th to 20th	Day	29% 19% 29% 18% 5% 1	674
	21st to end	Day	29% 18% 35% 15% 3 1	735
June	1st to 10th	Day	33% 18% 30% 14% 4	680
	11th to 20th	Day	28% 15% 33% 18% 5% 1	680
	21st to end	Day	34% 12% 31% 17% 6% 1	680
July	1st to 10th	Day	23% 10% 37% 21% 8% 1	670
	11th to 20th	Day	20% 10% 38% 22% 8% 1	668
	21st to end	Day	21% 10% 38% 23% 7% 1	666
August	1st to 10th	Day	18% 9% 38% 26% 7% 1	486
	11th to 20th	Day	22% 10% 35% 20% 10% 3	479
	21st to end	Day	17% 15% 34% 22% 9% 4	539
September	1st to 10th	Day	19% 14% 34% 23% 8% 1	490
	11th to 20th	Day	26% 15% 30% 19% 8% 3	490
	21st to end	Day	24% 16% 31% 19% 9% 2	457
October	1st to 10th	Day	23% 15% 33% 19% 9% 2	390
	11th to 20th	Day	28% 18% 30% 15% 6% 2	390
	21st to end	Day	30% 24% 27% 14% 4 1	429
November	1st to 10th	Day	32% 19% 29% 14% 5% 1	395
	11th to 20th	Day	41% 20% 24% 10% 5% 1	400
	21st to end	Day	37% 24% 26% 10% 2 1	400
December	1st to 10th	Day	40% 20% 27% 11% 2 1	400
	11th to 20th	Day	45% 21% 23% 10% 2	400
	21st to end	Day	35% 23% 29% 9% 3 1	440
January	1st to 10th	Night	32% 21% 31% 14% 2	900
	11th to 20th	Night	30% 23% 29% 15% 3	873
	21st to end	Night	25% 26% 31% 16% 2	880
February	1st to 10th	Night	31% 23% 29% 16% 2	800
	11th to 20th	Night	35% 26% 26% 12% 1	783
	21st to end	Night	23% 24% 30% 20% 3	660
March	1st to 10th	Night	29% 24% 31% 14% 2	800
	11th to 20th	Night	26% 20% 32% 18% 4	800
	21st to end	Night	30% 19% 32% 15% 4	880
April	1st to 10th	Night	34% 20% 27% 16% 2	606
	11th to 20th	Night	31% 21% 30% 15% 3	594
	21st to end	Night	29% 20% 30% 18% 4	600
May	1st to 10th	Night	33% 16% 31% 17% 3 1	600
	11th to 20th	Night	28% 13% 31% 23% 5%	565
	21st to end	Night	20% 17% 41% 20% 2	616
June	1st to 10th	Night	29% 15% 32% 22% 2	570
	11th to 20th	Night	23% 11% 36% 27% 3	465
	21st to end	Night	26% 6% 31% 31% 6%	380
July	1st to 10th	Night	20% 5% 37% 30% 8%	397
	11th to 20th	Night	18% 7% 37% 31% 7%	552
	21st to end	Night	18% 6% 33% 34% 8%	623
August	1st to 10th	Night	18% 6% 32% 35% 9% 1	568
	11th to 20th	Night	17% 8% 29% 34% 11% 1	562
	21st to end	Night	16% 8% 29% 34% 12%	627
September	1st to 10th	Night	16% 10% 33% 30% 10%	570
	11th to 20th	Night	21% 10% 27% 30% 12% 1	636
	21st to end	Night	24% 12% 30% 25% 9% 1	760
October	1st to 10th	Night	23% 11% 31% 26% 9% 1	760
	11th to 20th	Night	23% 16% 34% 19% 7% 1	760
	21st to end	Night	33% 18% 29% 17% 4	836
November	1st to 10th	Night	32% 15% 29% 19% 5% 1	873
	11th to 20th	Night	33% 19% 25% 18% 4	900
	21st to end	Night	34% 21% 26% 16% 2	900
December	1st to 10th	Night	34% 19% 29% 15% 3	900
	11th to 20th	Night	34% 25% 27% 11% 2	900
	21st to end	Night	33% 21% 27% 16% 3 1	990

Page generated at 2025-05-08 10:33:56. Version ac07

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