Rimouski
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rimouski clear sky chart from 2005-11-06 to 2024-03-18.

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	17% 10% 4 7% 7% 4 5% 5% 5% 6% 29%	78134
	Night	17% 12% 5% 9% 8% 4 5% 4 4 5% 24%	81669
Transparency	Day	55% 7% 13% 17% 8% 1	77825
	Night	61% 6% 11% 15% 7% 1	81513
Seeing	Day	22% 11% 28% 26% 11% 2	14950
	Night	23% 12% 28% 26% 10% 1	23133

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	13% 17% 7% 14% 16% 13% 5% 4 2 3 6%	2207
	11th to 20th	Day	11% 12% 5% 15% 21% 7% 6% 7% 4 4 8%	2431
	21st to end	Day	6% 10% 4 10% 12% 9% 9% 8% 5% 5% 21%	2772
February	1st to 10th	Day	8% 11% 6% 10% 11% 8% 8% 6% 6% 6% 21%	1607
	11th to 20th	Day	13% 15% 6% 11% 9% 5% 7% 5% 5% 4 19%	1667
	21st to end	Day	12% 10% 6% 9% 9% 6% 8% 6% 4 7% 24%	1570
March	1st to 10th	Day	15% 12% 6% 8% 8% 5% 7% 5% 6% 7% 24%	1897
	11th to 20th	Day	17% 14% 5% 9% 7% 4 5% 4 5% 5% 24%	2059
	21st to end	Day	15% 16% 5% 8% 6% 3 4 4 4 6% 29%	2181
April	1st to 10th	Day	20% 13% 5% 7% 6% 4 4 6% 4 6% 25%	2193
	11th to 20th	Day	19% 10% 4 6% 5% 3 4 4 5% 7% 34%	2312
	21st to end	Day	22% 10% 3 6% 4 3 3 4 5% 5% 34%	2340
May	1st to 10th	Day	23% 9% 3 6% 5% 3 4 5% 4 5% 32%	2340
	11th to 20th	Day	20% 8% 3 5% 4 3 4 5% 5% 6% 36%	2573
	21st to end	Day	21% 8% 2 5% 4 3 4 4 5% 7% 37%	2919
June	1st to 10th	Day	20% 8% 4 6% 5% 3 5% 5% 6% 7% 31%	2700
	11th to 20th	Day	20% 6% 2 5% 5% 2 5% 5% 6% 8% 37%	2700
	21st to end	Day	20% 7% 3 6% 6% 3 5% 5% 6% 8% 30%	2700
July	1st to 10th	Day	17% 6% 2 7% 6% 4 6% 5% 6% 8% 34%	2700
	11th to 20th	Day	15% 5% 2 6% 6% 4 5% 6% 6% 8% 38%	2700
	21st to end	Day	14% 6% 2 6% 6% 4 4 6% 7% 8% 38%	2763
August	1st to 10th	Day	15% 5% 2 6% 5% 3 6% 6% 8% 10% 34%	2419
	11th to 20th	Day	15% 6% 2 5% 5% 3 5% 5% 6% 7% 41%	2304
	21st to end	Day	16% 6% 2 5% 5% 3 5% 5% 6% 8% 38%	2574
September	1st to 10th	Day	18% 6% 2 4 4 3 4 4 5% 7% 42%	2166
	11th to 20th	Day	21% 6% 1 4 4 3 3 3 3 5% 46%	1980
	21st to end	Day	18% 6% 2 5% 6% 3 4 3 5% 6% 41%	1980
October	1st to 10th	Day	18% 9% 2 5% 5% 3 4 5% 5% 7% 37%	1890
	11th to 20th	Day	25% 10% 3 5% 6% 3 4 4 5% 6% 29%	1729
	21st to end	Day	26% 13% 2 5% 5% 3 4 5% 5% 6% 27%	1782
November	1st to 10th	Day	20% 13% 6% 8% 6% 3 5% 4 5% 5% 26%	1624
	11th to 20th	Day	20% 15% 6% 11% 6% 4 3 4 4 6% 21%	1520
	21st to end	Day	21% 16% 5% 12% 7% 4 3 4 4 5% 18%	1406
December	1st to 10th	Day	16% 18% 8% 15% 13% 5% 5% 4 4 4 10%	1330
	11th to 20th	Day	17% 17% 6% 13% 12% 6% 6% 3 3 3 15%	1668
	21st to end	Day	19% 11% 5% 11% 13% 5% 5% 4 4 5% 18%	2431
January	1st to 10th	Night	11% 17% 8% 16% 19% 8% 6% 3 3 3 6%	4748
	11th to 20th	Night	13% 16% 8% 12% 12% 6% 6% 5% 4 4 15%	4532
	21st to end	Night	7% 13% 6% 11% 11% 6% 8% 5% 4 6% 23%	4884
February	1st to 10th	Night	10% 12% 6% 11% 11% 6% 7% 5% 4 4 22%	2571
	11th to 20th	Night	13% 15% 8% 11% 10% 5% 6% 4 5% 5% 20%	2394
	21st to end	Night	12% 13% 5% 11% 10% 7% 6% 5% 4 5% 24%	1884
March	1st to 10th	Night	13% 14% 6% 10% 8% 4 7% 4 4 5% 25%	2269
	11th to 20th	Night	18% 17% 6% 9% 8% 5% 4 3 3 4 23%	2066
	21st to end	Night	17% 15% 6% 8% 6% 3 4 4 4 6% 28%	2174
April	1st to 10th	Night	24% 15% 4 9% 7% 3 4 3 4 4 23%	1766
	11th to 20th	Night	22% 10% 3 6% 4 3 5% 5% 5% 6% 32%	1598
	21st to end	Night	26% 10% 3 5% 3 3 3 3 4 6% 33%	1620
May	1st to 10th	Night	27% 9% 4 6% 6% 3 6% 4 4 5% 27%	1620
	11th to 20th	Night	20% 9% 4 6% 4 3 4 4 3 7% 36%	1335
	21st to end	Night	23% 8% 2 5% 6% 3 6% 4 5% 6% 31%	1356
June	1st to 10th	Night	20% 8% 3 8% 7% 3 4 6% 5% 7% 30%	1260
	11th to 20th	Night	20% 8% 3 6% 4 4 3 5% 7% 8% 33%	1260
	21st to end	Night	23% 7% 4 6% 6% 4 5% 5% 5% 6% 30%	1260
July	1st to 10th	Night	18% 7% 3 7% 5% 4 6% 5% 7% 8% 30%	1260
	11th to 20th	Night	12% 7% 3 7% 6% 4 5% 6% 7% 10% 32%	1260
	21st to end	Night	16% 7% 3 6% 6% 4 7% 6% 7% 9% 30%	1551
August	1st to 10th	Night	15% 6% 2 5% 7% 4 6% 6% 7% 9% 32%	1500
	11th to 20th	Night	16% 7% 3 6% 5% 3 5% 6% 7% 7% 34%	1596
	21st to end	Night	18% 6% 3 5% 6% 4 5% 5% 6% 7% 36%	1782
September	1st to 10th	Night	17% 6% 2 5% 6% 4 4 5% 6% 6% 40%	1789
	11th to 20th	Night	22% 7% 3 5% 4 3 3 4 4 6% 38%	1980
	21st to end	Night	19% 6% 2 5% 4 3 3 3 4 7% 44%	1980
October	1st to 10th	Night	19% 8% 2 5% 5% 4 5% 4 5% 5% 39%	2069
	11th to 20th	Night	26% 11% 3 6% 6% 3 3 4 5% 6% 27%	2227
	21st to end	Night	24% 13% 4 7% 5% 3 4 3 4 7% 27%	2574
November	1st to 10th	Night	21% 13% 4 9% 6% 4 4 4 4 5% 26%	2454
	11th to 20th	Night	21% 15% 6% 10% 5% 3 4 4 3 4 23%	2660
	21st to end	Night	19% 17% 7% 13% 8% 4 4 4 4 5% 16%	2773
December	1st to 10th	Night	20% 16% 7% 13% 11% 5% 5% 3 4 3 12%	2850
	11th to 20th	Night	18% 17% 6% 12% 13% 6% 5% 4 3 4 14%	3531
	21st to end	Night	17% 16% 6% 11% 11% 4 5% 4 4 5% 17%	5236

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	82% 7% 7% 4 1	2208
	11th to 20th	Day	75% 6% 9% 6% 3	2431
	21st to end	Day	60% 9% 10% 16% 4	2772
February	1st to 10th	Day	62% 7% 11% 12% 6% 1	1607
	11th to 20th	Day	67% 5% 12% 11% 4	1675
	21st to end	Day	60% 4 12% 18% 6%	1570
March	1st to 10th	Day	61% 5% 12% 15% 6% 1	1900
	11th to 20th	Day	61% 5% 11% 15% 8% 1	2059
	21st to end	Day	58% 4 10% 17% 9% 1	2181
April	1st to 10th	Day	60% 4 12% 15% 9% 1	2193
	11th to 20th	Day	50% 5% 14% 20% 11% 1	2312
	21st to end	Day	53% 5% 9% 19% 12% 2	2340
May	1st to 10th	Day	54% 6% 11% 17% 10% 2	2340
	11th to 20th	Day	48% 6% 11% 23% 12% 1	2577
	21st to end	Day	47% 7% 11% 23% 11% 1	2919
June	1st to 10th	Day	52% 7% 12% 16% 12% 1	2700
	11th to 20th	Day	46% 6% 13% 20% 13% 2	2700
	21st to end	Day	52% 8% 14% 16% 9% 1	2700
July	1st to 10th	Day	48% 8% 18% 20% 8%	2625
	11th to 20th	Day	42% 9% 17% 22% 9%	2619
	21st to end	Day	44% 10% 18% 21% 8%	2608
August	1st to 10th	Day	43% 10% 22% 20% 5%	2405
	11th to 20th	Day	41% 9% 21% 23% 6%	2304
	21st to end	Day	43% 7% 20% 22% 8%	2574
September	1st to 10th	Day	42% 7% 17% 24% 10%	2166
	11th to 20th	Day	42% 5% 16% 27% 10% 1	1980
	21st to end	Day	44% 7% 15% 23% 10%	1980
October	1st to 10th	Day	46% 6% 17% 21% 9% 1	1890
	11th to 20th	Day	56% 6% 16% 18% 4	1729
	21st to end	Day	58% 6% 14% 15% 6%	1782
November	1st to 10th	Day	59% 7% 14% 15% 5%	1624
	11th to 20th	Day	64% 6% 13% 13% 3	1520
	21st to end	Day	67% 5% 13% 12% 3	1406
December	1st to 10th	Day	78% 5% 9% 6% 1	1330
	11th to 20th	Day	73% 5% 8% 10% 3	1668
	21st to end	Day	67% 7% 11% 11% 3	2431
January	1st to 10th	Night	81% 8% 6% 4 1	4748
	11th to 20th	Night	68% 8% 10% 11% 4	4532
	21st to end	Night	59% 9% 9% 16% 6%	4884
February	1st to 10th	Night	64% 6% 9% 12% 7% 1	2571
	11th to 20th	Night	67% 5% 11% 12% 5%	2397
	21st to end	Night	62% 5% 9% 17% 6% 1	1884
March	1st to 10th	Night	62% 6% 8% 17% 7%	2279
	11th to 20th	Night	67% 3 8% 14% 8% 1	2067
	21st to end	Night	59% 5% 8% 17% 10% 1	2174
April	1st to 10th	Night	66% 4 7% 11% 11% 2	1766
	11th to 20th	Night	52% 6% 8% 18% 14% 1	1598
	21st to end	Night	55% 3 8% 19% 13% 1	1620
May	1st to 10th	Night	59% 5% 7% 16% 11% 2	1620
	11th to 20th	Night	50% 6% 10% 21% 12% 2	1336
	21st to end	Night	53% 6% 9% 17% 13% 2	1357
June	1st to 10th	Night	53% 6% 11% 18% 10% 2	1260
	11th to 20th	Night	49% 6% 10% 19% 13% 2	1260
	21st to end	Night	53% 8% 10% 17% 11%	1260
July	1st to 10th	Night	50% 9% 14% 20% 7%	1225
	11th to 20th	Night	44% 9% 17% 21% 9% 1	1218
	21st to end	Night	49% 10% 15% 19% 7%	1465
August	1st to 10th	Night	45% 11% 19% 21% 4	1490
	11th to 20th	Night	45% 11% 18% 18% 8% 1	1596
	21st to end	Night	44% 9% 16% 22% 8%	1782
September	1st to 10th	Night	42% 9% 14% 24% 10% 1	1789
	11th to 20th	Night	47% 5% 16% 22% 9% 1	1980
	21st to end	Night	43% 6% 13% 25% 13% 1	1980
October	1st to 10th	Night	47% 6% 13% 23% 11% 1	2069
	11th to 20th	Night	58% 5% 15% 18% 4	2227
	21st to end	Night	59% 5% 14% 16% 5% 1	2574
November	1st to 10th	Night	60% 5% 14% 15% 5% 1	2454
	11th to 20th	Night	64% 5% 12% 14% 4	2660
	21st to end	Night	72% 5% 12% 7% 3	2773
December	1st to 10th	Night	76% 5% 10% 8% 2	2850
	11th to 20th	Night	75% 5% 8% 9% 3	3532
	21st to end	Night	68% 7% 12% 9% 5%	5236

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	21% 14% 39% 18% 6% 1	180
	11th to 20th	Day	21% 21% 29% 22% 8%	180
	21st to end	Day	15% 13% 39% 18% 14% 1	198
February	1st to 10th	Day	15% 15% 39% 23% 6% 2	267
	11th to 20th	Day	16% 17% 38% 23% 6%	368
	21st to end	Day	16% 16% 36% 21% 8% 2	382
March	1st to 10th	Day	20% 15% 30% 28% 6% 1	460
	11th to 20th	Day	23% 17% 25% 19% 14% 2	449
	21st to end	Day	23% 12% 34% 22% 8% 2	462
April	1st to 10th	Day	25% 15% 28% 23% 8% 1	420
	11th to 20th	Day	23% 10% 29% 25% 10% 2	412
	21st to end	Day	24% 10% 33% 23% 6% 3	420
May	1st to 10th	Day	26% 10% 29% 25% 8% 2	423
	11th to 20th	Day	24% 8% 28% 27% 12% 2	574
	21st to end	Day	26% 10% 30% 23% 9% 2	680
June	1st to 10th	Day	23% 7% 30% 27% 10% 2	630
	11th to 20th	Day	23% 6% 26% 28% 15% 2	630
	21st to end	Day	21% 5% 24% 34% 14% 2	630
July	1st to 10th	Day	20% 4 28% 34% 12% 2	620
	11th to 20th	Day	15% 5% 24% 37% 17% 2	618
	21st to end	Day	14% 5% 25% 36% 17% 3	507
August	1st to 10th	Day	15% 6% 24% 35% 17% 3	446
	11th to 20th	Day	18% 5% 19% 37% 19% 3	439
	21st to end	Day	18% 8% 24% 29% 16% 5%	495
September	1st to 10th	Day	20% 6% 25% 28% 16% 4	450
	11th to 20th	Day	23% 10% 28% 24% 14% 2	450
	21st to end	Day	19% 11% 29% 26% 12% 4	450
October	1st to 10th	Day	20% 9% 32% 24% 12% 3	405
	11th to 20th	Day	31% 10% 24% 23% 11% 2	360
	21st to end	Day	33% 15% 25% 19% 7% 1	396
November	1st to 10th	Day	27% 18% 29% 21% 4	365
	11th to 20th	Day	29% 15% 28% 20% 8% 1	370
	21st to end	Day	25% 22% 30% 20% 4	256
December	1st to 10th	Day	25% 12% 31% 21% 9% 2	180
	11th to 20th	Day	25% 22% 34% 13% 6% 1	180
	21st to end	Day	23% 22% 32% 19% 3 1	198
January	1st to 10th	Night	22% 16% 37% 21% 5%	850
	11th to 20th	Night	22% 18% 33% 21% 5%	785
	21st to end	Night	14% 14% 35% 28% 9%	836
February	1st to 10th	Night	14% 16% 39% 23% 8% 1	760
	11th to 20th	Night	20% 15% 34% 22% 7% 1	743
	21st to end	Night	17% 13% 34% 26% 7% 2	628
March	1st to 10th	Night	19% 14% 31% 27% 8% 1	760
	11th to 20th	Night	25% 15% 29% 20% 9% 1	752
	21st to end	Night	23% 13% 29% 26% 7% 1	792
April	1st to 10th	Night	29% 12% 31% 19% 7% 1	686
	11th to 20th	Night	27% 9% 27% 26% 10% 1	534
	21st to end	Night	30% 9% 25% 25% 11% 1	540
May	1st to 10th	Night	30% 7% 22% 29% 10% 1	540
	11th to 20th	Night	22% 6% 26% 31% 13%	401
	21st to end	Night	27% 9% 26% 25% 11% 1	389
June	1st to 10th	Night	22% 6% 22% 37% 13% 1	360
	11th to 20th	Night	23% 6% 19% 36% 14% 2	360
	21st to end	Night	24% 5% 23% 33% 14% 1	360
July	1st to 10th	Night	18% 4 28% 34% 13% 3	350
	11th to 20th	Night	13% 3 25% 42% 16% 1	348
	21st to end	Night	18% 4 20% 40% 18% 1	394
August	1st to 10th	Night	17% 4 21% 38% 19% 2	426
	11th to 20th	Night	19% 2 22% 35% 21% 2	532
	21st to end	Night	18% 4 22% 37% 16% 3	594
September	1st to 10th	Night	20% 5% 25% 33% 16% 2	644
	11th to 20th	Night	24% 6% 26% 29% 12% 3	720
	21st to end	Night	20% 8% 29% 31% 11% 1	720
October	1st to 10th	Night	23% 9% 28% 28% 10% 2	720
	11th to 20th	Night	31% 8% 27% 23% 11% 1	720
	21st to end	Night	29% 15% 26% 22% 8%	792
November	1st to 10th	Night	28% 16% 29% 22% 5%	762
	11th to 20th	Night	27% 20% 27% 19% 6% 1	850
	21st to end	Night	25% 17% 31% 21% 6%	850
December	1st to 10th	Night	27% 16% 31% 19% 6% 1	850
	11th to 20th	Night	25% 20% 29% 20% 5% 1	850
	21st to end	Night	24% 18% 27% 22% 6% 1	935

Page generated at 2024-03-15 14:01:42. Version ac07

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